Pathogenic CD4+ T cells in patients with asthma

Diverse microbial exposure exacerbates the development of allergic airway inflammation in adult mice

Background

Exposure to a diversity of microbes has been implicated in playing a major role in susceptibility to the development of allergic lung type diseases. The hygiene hypothesis suggests that those exposed to a broad diversity of microbes are more likely to be protected against developing allergic type diseases. However, changes in exposure to microbial diversity can occur in both younger individuals, as well as in adults, and the effects are not always understood.

Objective

We investigated the effect of exposure to broad microbial diversity on the airway T cell response in house dust mite (HDM) induced allergic airway disease (AAD, a model of allergic asthma).

Methods

We increased exposure to broad microbial diversity by co-housing specific pathogen free (SPF) adult or newborn mice with pet store mice (PSE or BiPSE, respectively). Mice were then exposed to HDM to induce AAD.

Results

We found that the effect of increased microbial exposure on the development of allergic airway inflammation differs by age. Increasing exposure to diverse microbes as adults exacerbates the development of allergic airway inflammation, whereas this was not observed when exposure occurred at birth.

Conclusion

We suggest that experimental evaluation of the hygiene hypothesis in inflammation, particularly those using mouse models, may need to consider age of the host and time of microbial exposure.

Capsule Summary

Mouse models of increased exposure to diverse microbial environment shown to differentially affect the development of allergic airway inflammation, depending on the age of microbial exposure.

Integrative Roles of Pro-Inflammatory Cytokines on Airway Smooth Muscle Structure and Function in Asthma

Asthma has become more appreciated for its heterogeneity with studies identifying type 2 and non-type 2 phenotypes/endotypes that ultimately lead to airflow obstruction, airway hyperresponsiveness, and remodeling. The pro-inflammatory environment in asthma influences airway smooth muscle (ASM) structure and function. ASM has a vast repertoire of inflammatory receptors that, upon activation, contribute to prominent features in asthma, notably immune cell recruitment and activation, hypercontractility, proliferation, migration, and extracellular matrix protein deposition. These pro-inflammatory responses in ASM can be mediated by both type 2 (e.g., IL-4, IL-13, and TSLP) and non-type 2 (e.g., TNFα, IFNγ, IL-17A, and TGFβ) cytokines, highlighting roles for ASM in type 2 and non-type 2 asthma phenotypes/endotypes. In recent years, there has been considerable advances in understanding how pro-inflammatory cytokines promote ASM dysfunction and impair responsiveness to asthma therapy, corticosteroids and long-acting β2-adrenergic receptor agonists (LABAs). Transcriptomic analyses on human ASM cells and tissues have expanded our knowledge in this area but have also raised new questions regarding ASM and its role in asthma. In this review, we discuss how pro-inflammatory cytokines, corticosteroids, and LABAs affect ASM structure and function, with particular focus on changes in gene expression and transcriptional programs in type 2 and non-type 2 asthma.

Correlation between peripheral blood iNKT cell levels and exhaled NO in patients with allergic rhinitis

OBJECTIVES

This study aimed to investigate the relationship between the frequency of CD3 + TCRVα24 + iNKT cells, the proportions of iNKT CD4+, iNKT CD8 + and iNKT CD4-CD8- (DN) subgroups in peripheral blood, and nasal exhaled nitric oxide (NO) levels in patients with allergic rhinitis (AR).

METHODS

Peripheral blood samples were collected from 40 AR patients and 40 patients with nasal septal deviation (DNS). The frequencies of the iNKT cell subgroups were analyzed, and nasal exhaled NO levels were measured. Correlation analyses were conducted to assess the associations between these parameters..

RESULTS

The frequency of CD3 + TCRVα24 + iNKT cells was significantly higher in the AR group (0.4863 % ± 0.0874 %) compared to the DNS group (0.4451 % ± 0.0603 %) (p < 0.05). The proportions of iNKT CD4+, iNKT CD8+, and iNKT CD4-CD8- (DN) cells in the AR group were 76.32 % ± 10.24 %, 12.71 % ± 4.34 %, and 11.08 % ± 6.29 %, respectively, while in the DNS group, they were 60.79 % ± 9.04 %, 13.81 % ± 5.56 %, and 25.56 % ± 6.45 %. Significant differences were observed in the proportions of iNKT CD4+ and iNKT CD4-CD8- (DN) cells between the two groups (p < 0.01). Nasal exhaled NO levels were significantly elevated in the AR group (842.33 ± 237.88 ppb) compared to the DNS group (527.37 ± 163.57 ppb, p < 0.01). In the AR group, nasal exhaled NO levels showed a strong positive correlation with the frequency of iNKT cells (r = 0.9, p < 0.01), the iNKT CD4+ subgroup (r = 0.93, p < 0.01), and a negative correlation with the iNKT CD4-CD8- (DN) subgroup (r = -0.877, p < 0.01). These findings suggest that elevated iNKT cells, particularly the iNKT CD4+ subgroup resembling T helper 2 (Th2) cells, may contribute to AR pathogenesis.

CONCLUSIONS

The significant correlations between iNKT cell subgroups and nasal exhaled NO levels highlight the role of iNKT cell variations in NO-mediated AR pathogenesis. These findings also suggest the potential diagnostic value of analyzing iNKT cell profiles in AR patients.

Distinct single-cell transcriptional profile in CD4+ T-lymphocytes among obese children with asthma

Obesity is a risk factor for asthma morbidity, associated with less responsiveness to inhaled corticosteroids. CD4+ T cells are central to the immunology of asthma and may contribute to the unique obese asthma phenotype. We sought to characterize the single-cell CD4+ transcriptional profile differences in obese children with asthma compared with normal-weight children with asthma. Eight normal-weight and obese participants with asthma were clinically phenotyped and matched based on asthma control. Peripheral blood (PB) CD4+ T cells were sorted, and single-cell RNA sequencing was conducted. Cell clusters were identified by canonical gene expression and differential gene expression and reactome pathway analysis was applied. The obese PB bulk transcriptomic signature from the U-BIOPRED pediatric cohort was assessed in our cohort as well. Obese children with asthma have a distinct CD4+ transcriptional profile with differential gene expression. There were more activated protein tyrosine phosphate receptor type C (PTPRC)high cells and less PTPRClow in children with obesity. Children with obesity had higher enrichment of the neutrophil degranulation, interleukin-7 (IL-7) receptor, and IL-7-related janus kinase-signal transducer and activator of transcription signaling pathways. Genes previously associated with more severe asthma, IL-32, FKBP5 gene expression, IL-6, and Rho transcriptional signaling, were also enriched in obese children with asthma. Our findings shed insight into the molecular mechanisms underpinning more severe and steroid-resistant asthma among children with obesity. Further investigation is needed to identify potential new therapeutic targets for this group.NEW & NOTEWORTHY This study identified unique contributors to asthma in children with obesity and found novel pathways. Increased expression of IL-7R, IL-32, PARP-1, FKBP5 gene, IL-6, and Rho transcriptional signaling were observed in obese individuals with asthma.

Apex1 safeguards genomic stability to ensure a cytopathic T cell fate in autoimmune disease models

T cells have a remarkable capacity to clonally expand, a process that is intricately linked to their effector activities. As vigorously proliferating T cell also incur substantial DNA lesions, how the dividing T cells safeguard their genomic integrity to allow the generation of T effector cells remains largely unknown. Here we report the identification of the apurinic/apyrimidinic endonuclease-1 (Apex1) as an indispensable molecule for the induction of cytopathic T effectors in mouse models. We demonstrate that conditional deletion of Apex1 in T cells resulted in a remarkable accumulation of baseless DNA sites in the genome of proliferating T cells, which further led to genomic instability and apoptotic cell death. Consequently, Apex1-deleted T cells failed to acquire any effector features after activation and failed to mediate autoimmune diseases and allergic tissue damages. Detailed mutational analyses pinpointed the importance of its endonuclease domain in the generation of T effector cells. We provide further evidence that inhibiting the base repair activities of Apex1 with chemical inhibitors similarly abrogated the induction of autoimmune diseases. Collectively, our study suggests that Apex1 serves as a gatekeeper for the generation of cytopathic T cells and that therapeutically targeting Apex1 may have important clinical implications in the treatment of autoimmune diseases.

Fine-tuning levels of filamins a and b as a specific mechanism sustaining Th2 lymphocyte functions

Augmenting the portfolio of therapeutics for type 2-driven diseases is crucial to address unmet clinical needs and to design personalized treatment schemes. An attractive therapy for such diseases would consist in targeting the recruitment of T helper 2 (Th2) lymphocytes to inflammatory sites. Herein, we show the degradation of filamins (FLN) a and b by the ASB2α E3 ubiquitin ligase as a mechanism sustaining Th2 lymphocyte functions. Low levels of FLNa and FLNb confer an elongated shape to Th2 lymphocytes associated with efficient αVβ3 integrin-dependent cell migration. Genes encoding the αVβ3 integrin and ASB2α belong to the core of Th2-specific genes. Using genetically modified mice, we find that increasing the levels of FLNa and FLNb in Th2 lymphocytes reduces airway inflammation through diminished Th2 lymphocyte recruitment in inflamed lungs. Collectively, our results highlight ASB2α and its substrates FLNa and FLNb to alter Th2 lymphocyte-mediated responses.

LPG 18:0 is a general biomarker of asthma and inhibits the differentiation and function of regulatory T-cells

BACKGROUND

The diagnosis, severity assessment, and development of therapeutic strategies for asthma are crucial aspects of disease management. Since biomarkers are reliable tools in disease management, we aimed to identify and explore asthma-associated biomarkers and investigate their mechanisms.

METHODS

Lipidomics was used to profile serum glycerophospholipids in asthmatic patients and controls. The absolute concentration of lysophosphatidylglycerol (LPG) 18:0 was quantified in various asthma subtypes. Mouse asthma models were used to confirm its potential as a biomarker and investigate its mechanisms in vivo. The effects of LPG 18:0 on CD4+ T-cell differentiation, proliferation and apoptosis were assessed in vitro by flow cytometry, while mitochondrial dysfunction was evaluated through mitochondrial membrane potential, reactive oxygen species and ATP production measurements. The intracellular mechanism of LPG 18:0 in regulatory T-cells (Tregs) was investigated using small-molecule inhibitors.

RESULTS

The serum glycerophospholipid profile varied between asthmatic patients and control group, with LPG 18:0 levels being notably higher in asthmatic patients, correlating with asthma severity and control level. In vivo and in vitro studies revealed that LPG 18:0 impaired naïve CD4+ T-cell differentiation into Tregs and compromised their suppressive function. Further investigation demonstrated that LPG 18:0 treatment reduced the FOXP3 protein level via SIRT1-mediated deacetylation during Treg differentiation.

CONCLUSIONS

This study identifies that serum levels of LPG 18:0 are generally elevated in asthmatics and serve as a biomarker for asthma. LPG 18:0 impairs Treg function via the NAD+/SIRT1/FOXP3 pathway. Our research reveals the potential of LPG 18:0 as a biomarker for asthma, elucidating its role in asthma diagnosis and treatment.

Bifidobacterium breve DSM 32583 and Limosilactobacillus fermentum CECT5716 postbiotics attenuate S. aureus and IL-33-induced Th2 responses

Over the past decades, the prevalence of allergic diseases noticeably increased in industrialized countries. The Th2 immune response plays a central role in these pathologies and its modulation using pro-/postbiotics constitutes a promising approach to prevent or alleviate disease symptoms. The aim of this in vitro study, was to investigate the ability of human milk-derived Bifidobacterium breve DSM 32583 (Bb) and Limosilactobacillus fermentum CECT5716 (Lf), to modulate the Th2 induced responses. To this end, Th2 cells were generated by co-culturing of human naïve Th cells with monocyte-derived dendritic cells (moDCs) either stimulated with Staphylococcus aureus or IL-33. The immunomodulatory effects of pro-/postbiotic preparations of Bb and Lf on moDCs and Th2 cells were evaluated in terms of maturation markers expression and cytokines production. Remarkably, the tested strains induced the anti-inflammatory cytokine IL-10 in moDCs, in a strain-, dose- and viability-dependent manner with no significant upregulation of IL-12p70 nor CD83, CD86 or HLA-DR. Interestingly, Bb and Lf postbiotics were able to dampen the Th2/Th1 response induced upon S. aureus- or IL-33 stimulation. They were also able to synergistically induce IL-10 in moDCs and T cells, upon co-stimulation with LPS. Finally, we observed that live probiotics triggered a mild Th1 response that was attenuated in the presence of galacto-oligosaccharides. Altogether, Bb and Lf pro-/postbiotics exhibited remarkable immune regulatory effects on both moDCs and Th2 cells. Therefore, further in vivo studies should be considered to validate these findings and assess their ability to prevent allergy or alleviate its symptoms in affected patients.

Single-cell RNA sequencing reveals transcriptional changes in circulating immune cells from patients with severe asthma induced by biologics

Patients with severe eosinophilic asthma often require systemic medication, including corticosteroids and anti-type 2 (T2) cytokine biologics, to control the disease. While anti-IL5 and anti-IL4Rα antibodies suppress the effects of IL-4, IL-5 and IL-13, the molecular pathways modified by these biologics that are associated with clinical improvement remain unclear. Therefore, we aimed to describe the effects of T2-targeting biologics on the gene expression of blood immune cells. We conducted single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) from eight patients with severe eosinophilic asthma treated with mepolizumab, reslizumab, or dupilumab. PBMCs were obtained before the initiation of biologics and at 1- and 6-month timepoints after the initiation of treatment to elucidate treatment-induced changes. During treatment, the proportions of T cells/natural killer (NK) cells, myeloid cells, and B cells did not change. However, the composition of classical monocytes (CMs) changed: IL1B+ CMs were reduced, and S100A+ CMs were increased. The subsets of T cells also changed, and significant downregulation of the NF-κB pathway was observed. The genes related to the NF-κB pathway were suppressed across T/NK, myeloid, and B cells. The transcriptional landscape did not significantly change after the first month of treatment, but marked changes occurred at six-month intervals. In conclusion, regardless of the type of biologics used, suppression of T2-mediated pathways ultimately reduces the expression of genes related to NF-κB signaling in circulating immune cells. Further studies are warranted to identify potential biomarkers related to treatment response and long-term outcomes.Clinical trial registration number: NCT05164939.

Correlation between systemic allergen desensitisation and long-term asthma protection in mice following intravenous administration of the live tuberculosis vaccine MTBVAC

BACKGROUND

MTBVAC is a live attenuated tuberculosis vaccine, currently undergoing phase III evaluation for tuberculosis prevention. In previous preclinical studies, we found that local pulmonary administration of MTBVAC via the intranasal route had a strong therapeutic effect against asthma. This effect correlated with the abrogation of allergen-specific Th2 response in the lungs.

METHODS

Using different mouse models of asthma, we investigated the effect of MTBVAC administered by intravenous (IV) route and its potential as immunotherapeutic agent to induce desensitisation of allergen-specific responses at a systemic level. We explored the effects of this process in the efficacy against airway hyperresponsiveness (AHR) induced by exposure to different allergens.

FINDINGS

IV MTBVAC was highly efficient at reducing AHR induced by different allergens. Additionally, IV MTBVAC was found to be well-tolerated, being progressively eliminated from the different organs analysed. From a mechanistic standpoint, we observed that MTBVAC intravenous, but not intranasal, impaired allergen-specific Th2 response in both lungs and spleen. This reduction at a systemic level correlated with long-term therapeutic protection against allergen exposure. Our results also revealed differential immunological mechanisms governing systemic and local pulmonary allergen desensitisation processes. Notably, in a cohort of patients with asthma sensitive to house dust mite (HDM), in vitro incubation of peripheral blood mononuclear cells (PBMCs) with MTBVAC prevented allergen-specific production of Th2 cytokines IL-4 and IL-5.

INTERPRETATION

Altogether, our results suggest that intravenous MTBVAC could be a plausible allergen desensitising approach for treatment of asthma, and could provide long-term protection against allergen exposure.

FUNDING

MCIN/AEI/10.13039/501100011033 [grants number RTI2018-097625-B-I00 and PID2022-138624OB-I00]; Consorcio Centro de Investigación Biomédica en Red- (Groups CB06/06/0020 and CB06/06/0013), Instituto de Salud Carlos III.

Exhaled breath analysis for the discrimination of asthma and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) and asthma are the most common chronic respiratory diseases. In middle-aged and elderly patients, it is difficult to distinguish between COPD and asthma based on clinical symptoms and pulmonary function examinations in clinical practice. Thus, an accurate and reliable inspection method is required. In this study, we aimed to identify breath biomarkers and evaluate the accuracy of breathomics-based methods for discriminating between COPD and asthma. In this multi-center cross-sectional study, exhaled breath samples were collected from 89 patients with COPD and 73 with asthma and detected on a high-pressure photon ionization time-of-flight mass spectrometry (HPPI-TOFMS) platform from 20 October 2022, to 20 May 2023, in four hospitals. Data analysis was performed from 15 June 2023 to 16 August 2023. The sensitivity, specificity, and accuracy were calculated to assess the overall performance of the volatile organic component (VOC)-based COPD and asthma discrimination models. Potential VOC markers related to COPD and asthma were also analyzed. The age of all participants ranged from to 18-86 years, and 54 (33.3%) were men. The age [median (minimum, maximum)] of COPD and asthma participants were 66.0 (46.0, 86.0), and 44.0 (17.0, 80.0). The male and female ratio of COPD and asthma participants were 14/75 and 40/33, respectively. Based on breathomics feature selection, ten VOCs were identified as COPD and asthma discrimination biomarkers via breath testing. The joint panel of these ten VOCs achieved an area under the curve of 0.843, sensitivity of 75.9%, specificity of 87.5%, and accuracy of 80.0% in COPD and asthma discrimination. Furthermore, the VOCs detected in the breath samples were closely related to the clinical characteristics of COPD and asthma. The VOC-based COPD and asthma discrimination model showed good accuracy, providing a new strategy for clinical diagnosis. Breathomics-based methods may play an important role in the diagnosis of COPD and asthma.

Cytotoxic CD4+ tissue-resident memory T cells are associated with asthma severity

BACKGROUND

Patients with severe uncontrolled asthma represent a distinct endotype with persistent airway inflammation and remodeling that is refractory to corticosteroid treatment. CD4+ TH2 cells play a central role in orchestrating asthma pathogenesis, and biologic therapies targeting their cytokine pathways have had promising outcomes. However, not all patients respond well to such treatment, and their effects are not always durable nor reverse airway remodeling. This observation raises the possibility that other CD4+ T cell subsets and their effector molecules may drive airway inflammation and remodeling.

METHODS

We performed single-cell transcriptome analysis of >50,000 airway CD4+ T cells isolated from bronchoalveolar lavage samples from 30 patients with mild and severe asthma.

FINDINGS

We observed striking heterogeneity in the nature of CD4+ T cells present in asthmatics' airways, with tissue-resident memory T (TRM) cells making a dominant contribution. Notably, in severe asthmatics, a subset of CD4+ TRM cells (CD103-expressing) was significantly increased, comprising nearly 65% of all CD4+ T cells in the airways of male patients with severe asthma when compared to mild asthma (13%). This subset was enriched for transcripts linked to T cell receptor activation (HLA-DRB1, HLA-DPA1) and cytotoxicity (GZMB, GZMA) and, following stimulation, expressed high levels of transcripts encoding for pro-inflammatory non-TH2 cytokines (CCL3, CCL4, CCL5, TNF, LIGHT) that could fuel persistent airway inflammation and remodeling.

CONCLUSIONS

Our findings indicate the need to look beyond the traditional T2 model of severe asthma to better understand the heterogeneity of this disease.

FUNDING

This research was funded by the NIH.

Anti-CD3 inhibits circulatory and tissue-resident memory CD4 T cells that drive asthma exacerbations in mice

BACKGROUND

Exacerbations of asthma are thought to be strongly dependent on reactivation of allergen-induced lung tissue-resident and circulatory memory CD4 T cells. Strategies that broadly inhibit multiple T cell populations might then be useful to limit asthma. Accordingly, we tested whether targeting CD3 during exposure to inhaled allergen could prevent the accumulation of lung-localized effector memory CD4 T cells and block exacerbations of asthmatic inflammation.

METHODS

House dust mite-sensitized and repetitively challenged BL/6 mice were transiently treated therapeutically with F(ab')2 anti-CD3ε and memory T cell responses and lung inflammation were assessed. PBMCs from HDM-allergic donors were examined for the effect of anti-CD3 on expansion of allergen-reactive T cells.

RESULTS

Allergen-sensitized mice undergoing exacerbations of asthma were protected from lung inflammation by transient therapeutic treatment with F(ab')2 anti-CD3. Regardless of whether sensitized mice underwent a secondary or tertiary recall response to inhaled allergen, anti-CD3 inhibited all phenotypes of effector memory CD4 T cells in the lung tissue and lung vasculature by 80%-90%, including those derived from tissue-resident and circulatory memory T cells. This did not depend on Treg cells suggesting it was primarily a blocking effect on memory T cell signaling. Correspondingly, anti-CD3 also strongly inhibited proliferation of human allergen-reactive memory CD4 T cells from allergic individuals. In contrast, the number of surviving tissue-resident memory CD4 T cells that were maintained in the lungs at later times was not robustly reduced by anti-CD3.

CONCLUSION

Anti-CD3 F(ab')2 administration at the time of allergen exposure represents a viable strategy for limiting the immediate activity of allergen-responding memory T cells and asthma exacerbations.

Effects of theophylline combined with inhaled corticosteroids on patients with moderate and severe asthma and changes of T lymphocyte subsets in peripheral blood

Introduction

Asthma is a common respiratory disease. Theophylline combined with inhaled corticosteroids (ICS) is a promising therapy for asthma. This study explored the therapeutic effects of ICS combined with theophylline on moderate and severe asthma patients and T lymphocyte subsets (CD3+CD8+ T cells) in peripheral blood.

Material and methods

A total of 202 moderate and severe asthma patients were selected, with 101 treated with theophylline combined with ICS and 101 treated with ICS alone as controls. Lung function [forced expiratory volume within 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF)] were tested using a spirometer. Asthma symptom control was evaluated by asthma control tests (ACT). The life quality was evaluated using the Asthma Quality of Life Questionnaire (AQLQ). The number and percentage of CD3+ T, CD3+CD4+ T and CD3+CD8+ T cells in peripheral blood mononuclear cells were assessed by flow cytometry. The correlation between CD3+CD8+ T cells and lung function and asthma control of patients after combination therapy was analyzed by Pearson correlation analysis.

Results

Compared with moderate and severe patients treated with ICS alone, theophylline improved the efficacy of ICS. Theophylline combined with ICS decreased IL-4 and IL-6 levels, and CD3+ T and CD3+CD8+ T cell number and percentage. After combined treatment, CD3+ CD8+ T cells in peripheral blood of patients were positively correlated with lung function and negatively correlated with asthma control.

Conclusions

The additional use of theophylline improved the efficacy of corticosteroids in asthma patient treatment and reduced inflammation level and CD3+ T and CD3+CD8+ T cell contents in peripheral blood.

New insights into the pathophysiology and therapeutic targets of asthma and comorbid chronic rhinosinusitis with or without nasal polyposis

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) or without (CRSsNP) are chronic respiratory diseases. These two disorders often co-exist based on common anatomical, immunological, histopathological, and pathophysiological basis. Usually, asthma with comorbid CRSwNP is driven by type 2 (T2) inflammation which predisposes to more severe, often intractable, disease. In the past two decades, innovative technologies and detection techniques in combination with newly introduced targeted therapies helped shape our understanding of the immunological pathways underlying inflammatory airway diseases and to further identify several distinct clinical and inflammatory subsets to enhance the development of more effective personalized treatments. Presently, a number of targeted biologics has shown clinical efficacy in patients with refractory T2 airway inflammation, including anti-IgE (omalizumab), anti-IL-5 (mepolizumab, reslizumab)/anti-IL5R (benralizumab), anti-IL-4R-α (anti-IL-4/IL-13, dupilumab), and anti-TSLP (tezepelumab). In non-type-2 endotypes, no targeted biologics have consistently shown clinical efficacy so far. Presently, multiple therapeutical targets are being explored including cytokines, membrane molecules and intracellular signalling pathways to further expand current treatment options for severe asthma with and without comorbid CRSwNP. In this review, we discuss existing biologics, those under development and share some views on new horizons.

Regulation of c-SMAC formation and AKT-mTOR signaling by the TSG101-IFT20 axis in CD4+ T cells

CD4+ T cells play major roles in the adaptive immune system, which requires antigen recognition, costimulation, and cytokines for its elaborate orchestration. Recent studies have provided new insight into the importance of the supramolecular activation cluster (SMAC), which comprises concentric circles and is involved in the amplification of CD4+ T cell activation. However, the underlying mechanism of SMAC formation remains poorly understood. Here, we performed single-cell RNA sequencing of CD4+ T cells left unstimulated and stimulated with anti-CD3 and anti-CD28 antibodies to identify novel proteins involved in their regulation. We found that intraflagellar transport 20 (IFT20), previously known as cilia-forming protein, was upregulated in antibody-stimulated CD4+ T cells compared to unstimulated CD4+ T cells. We also found that IFT20 interacted with tumor susceptibility gene 101 (TSG101), a protein that endocytoses ubiquitinated T-cell receptors. The interaction between IFT20 and TSG101 promoted SMAC formation, which led to amplification of AKT-mTOR signaling. However, IFT20-deficient CD4+ T cells showed SMAC malformation, resulting in reduced CD4+ T cell proliferation, aerobic glycolysis, and cellular respiration. Finally, mice with T-cell-specific IFT20 deficiency exhibited reduced allergen-induced airway inflammation. Thus, our data suggest that the IFT20-TSG101 axis regulates AKT-mTOR signaling via SMAC formation.

Intestinal Microflora Altered by Vancomycin Exposure in Early Life Up-regulates Type 2 Innate Lymphocyte and Aggravates Airway Inflammation in Asthmatic Mice

Allergic asthma is a chronic inflammatory disease primarily mediated by Th2 immune mechanisms. Exposure to antibiotics during early life is associated with an increased risk of allergic asthma, although the exact mechanism is not fully understood. In this study, mice were randomly divided into a normal saline control group (NS group), an OVA-induced asthma group (OVA group), a vancomycin treatment control group (VAN.NS group), and a vancomycin treatment the OVA-induced asthma group (VAN.OVA group). The results showed that vancomycin altered dominant species in experimental mice. The phylum level histogram showed that Bacteroides abundance was increased, and Firmicutes abundance was decreased in the OVA group. Airway inflammation and airway hyperresponsiveness (AHR) were aggravated in the vancomycin-exposed group. Enzyme-linked immunosorbent assay (ELISA) showed that the serum levels of IL-5, IL-13, and IL-33 in the OVA group were higher than those in the NS group, especially in the VAN.OVA group. The expression of GATA binding protein-3(GATA3) and retinoid acid receptor-related orphan receptor alpha (RORa) increased in the OVA group, even more so in the VAN.OVA group. Group 2 innate lymphoid cells (ILC2s) in the lung detected by flow cytometry was increased in OVA mice more than those in control mice, with a more remarkable increase in the VAN.OVA. Our results demonstrated that vancomycin used in early life could alter the intestinal microecology of mice, which, in turn, aggravates airway inflammation and upregulate type 2 innate lymphocytes.

Apolipoprotein E negatively regulates allergic airway inflammation and remodeling in mice with OVA-induced chronic asthma

Apolipoprotein E (ApoE) is a corticosteroid-unresponsive gene that negatively regulates ovalbumin (OVA) -induced allergic airway inflammation in mice with acute asthma. However, whether ApoE negatively regulates airway remodeling in mice with OVA-induced chronic asthma remains unknown. This study aimed to investigate the effects of ApoE on OVA-induced chronic asthma in a murine model. ApoE knockout (ApoE^-/-) and wild-type (WT) mice were sensitized and challenged with OVA for 10 weeks to establish the chronic asthma model. Compared with WT mice, the results demonstrated that ApoE deficiency exacerbated OVA-induced airway inflammation, including elevated numbers of inflammatory cells in the blood and bronchoalveolar lavage fluid (BALF), as well as increased T helper type 2 (Th2) cells in lung tissue, Th2 cytokines in BALF, and total IgE levels in plasma. Importantly, ApoE deficiency aggravated OVA-induced airway remodeling, as evidenced by higher plasma transforming growth factor (TGF)-β1 levels, airway goblet cell hyperplasia, and collagen deposition compared with WT mice. These results revealed that ApoE deficiency aggravates airway remodeling and inflammation in mice with OVA-induced chronic allergic asthma.

Persisting Cryptococcus yeast species Vishniacozyma victoriae and Cryptococcus neoformans elicit unique airway inflammation in mice following repeated exposure

Background

Allergic airway disease (AAD) is a growing concern in industrialized nations and can be influenced by fungal exposures. Basidiomycota yeast species such as Cryptococcus neoformans are known to exacerbate allergic airway disease; however, recent indoor assessments have identified other Basidiomycota yeasts, including Vishniacozyma victoriae (syn. Cryptococcus victoriae), to be prevalent and potentially associated with asthma. Until now, the murine pulmonary immune response to repeated V. victoriae exposure was previously unexplored.

Objective

This study aimed to compare the immunological impact of repeated pulmonary exposure to Cryptococcus yeasts.

Methods

Mice were repeatedly exposed to an immunogenic dose of C. neoformans or V. victoriae via oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and lungs were collected to examine airway remodeling, inflammation, mucous production, cellular influx, and cytokine responses at 1 day and 21 days post final exposure. The responses to C. neoformans and V. victoriae were analyzed and compared.

Results

Following repeated exposure, both C. neoformans and V. victoriae cells were still detectable in the lungs 21 days post final exposure. Repeated C. neoformans exposure initiated myeloid and lymphoid cellular infiltration into the lung that worsened over time, as well as an IL-4 and IL-5 response compared to PBS-exposed controls. In contrast, repeated V. victoriae exposure induced a strong CD4+ T cell-driven lymphoid response that started to resolve by 21 days post final exposure.

Discussion

C. neoformans remained in the lungs and exacerbated the pulmonary immune responses as expected following repeated exposure. The persistence of V. victoriae in the lung and strong lymphoid response following repeated exposure were unexpected given its lack of reported involvement in AAD. Given the abundance in indoor environments and industrial utilization of V. victoriae, these results highlight the importance to investigate the impact of frequently detected fungal organisms on the pulmonary response following inhalational exposure. Moreover, it is important to continue to address the knowledge gap involving Basidiomycota yeasts and their impact on AAD.

Transcriptomic analysis of asthma and allergic rhinitis reveals CST1 as a biomarker of unified airways

Background

Allergic rhinitis (AR) is an important risk factor for the development of asthma. The "unified airway" theory considers the upper and lower airways as a morphological and functional whole. However, studies exploring biomarkers linking the upper and lower airways in allergic disease are lacking, which may provide insight into the mechanisms underlying AR comorbid asthma.

Purpose

To integrate bioinformatics techniques to explore biomarkers in airway allergic diseases, and to provide a molecular etiology profile for preventing the development of asthma in AR patients.

Methods

Biomarkers were screened by identifying key genes common between AR and asthma through WGCNA and differential gene analysis. GO and KEGG analyses were performed using DAVID. Immuno-infiltration analysis was performed by CIBERSORTx. The predictive value of CST1 to distinguish Th2-high asthma was determined by ROC curves. GSEA was used to analyze the signaling pathways involved in CST1. TargetScan and miRNet were combined with GSE142237 to construct ceRNA network. CMap was used to explore potential therapeutic drugs.

Results

Validation of datasets showed that CST1 was the only gene that was up-regulated in both upper and lower airways in patients with AR and asthma, and correlation heatmaps showed that CST1 was the gene with the highest sum of correlation coefficients. GO and KEGG analysis demonstrated that the lower airways of AR patients were mainly involved in inflammatory and immune responses, similar to asthma. Immune infiltration showed that CST1 was mainly positively correlated with activated CD4 memory T cells. According to the ROC curve, CST1 showed excellent diagnostic efficiency for Th2-high asthma. GSEA indicated that CST1 was involved in the FcϵRI signaling pathway and O-glycan biosynthesis. A ceRNA network including the lncRNAs KCNQ1OT1 and NEAT1 was constructed. Four drugs, including verrucarin-A, had the potential to prevent the development of asthma in AR patients. In addition, corticosteroids were found to downregulate CST1 expression.

Conclusion

CST1 plays a key role in the development of AR comorbid asthma and may be a biomarker for airway allergic diseases. Targeted treatment of CST1 has the potential to prevent the development of asthma in AR patients and deserves further study.

Transfer factors peptides (Imuno TF®) modulate the lung inflammation and airway remodeling in allergic asthma

Background

Allergic asthma is a chronic lung disease in which the lung inflammation and airway remodeling are orchestrated by both the inflammatory and the immune cells that creates a lung millieu that favors the perpetuation of clinical symptoms. The cell signaling in asthma involves the mast cells activation during initial contact with the allergen and, principally, the participation of eosinophils as well as Th2 cells which determine increased levels of IgE, exaggerated secretion of mucus and collagen, and bronchial hyperreactivity. Moreover, allergic asthma presents lower level of cytokines associated to the both Th1 and Treg cells response, and it implies in deficiency of anti-inflammatory response to counterregulate the exaggerated inflammation against allergen. Therefore, the equilibrium between cytokines as well as transcription factors associated to Th2, Th1, and Treg cells is compromised in allergic asthma. Imuno TF® is a food supplement with ability to interfere in immune system pathways. It has been previously demonstrated that Imuno TF® upregulated Th1 cell response whilst downregulated Th2 cell response in human lymphocytes.

Objective

For this reason, we hypothesized that the Imuno TF effect could be restore the balance between Th1/Th2 CD4 T cells response in murine allergic asthma.

Methods

Initially, animals were sensitized with OVA via i.p. and challenged with OVA i.n. on days 14, 15 and 16. Treatment with Imuno TF once a day was performed via orogastric from day 17 to day 20. Mice were euthanized on day 21.

Results

The Imuno TF reduced eosinophilia, mucus production, and airway remodeling (collagen deposition) in asthma mice. Imuno TF influenced cellular signaling associated to allergic asthma once downregulated STAT6 expression as well as decreased IL-4, IL-5, and IL-13 in lung and serum. In addition, Imuno TF restored T-bet and Foxp3 expression as well as increased IL-12, IFN-ɣ, and IL-10.

Conclusion

Ultimately, Imuno TF mitigated the allergic asthma due to the restoration of balance between the responses of Th1/Th2 as well as Treg cells, and their respective transcription factors the T-bet/STAT6 and Foxp3.

Lncrna NEAT1 Regulates Th1/Th2 in Pediatric Asthma by Targeting MicroRNA-217/GATA3

Background

The imbalance of immune response between helper Th1 and Th2 cells is the direct cause of asthma. It was closely related to abnormal expression of lncRNAs. However, whether lncRNAs can regulate Th1/Th2 balance in pediatric asthma remains to be investigated.

Methods

Peripheral blood samples were collected from children with asthma and normal volunteers at the Children's Hospital of Shaanxi Provincial People's Hospital (Xi'an, China) in 2020. The qRT-PCR was used to detect the expression of lncRNA NEAT1, miR-217 and GATA3 in peripheral blood samples. The effects of lncRNA NEAT1, miR-217, and GATA3 on CD4+T cell population were detected in vitro. Meanwhile, the regulatory effect of lncRNA NEAT1/miR-217/GATA3 was evaluated through the dual luciferase report assay, functional assays and animal experiments.

Results

We investigated that lncRNA NEAT1 and GATA3 was significantly up-regulated in CD4+T cells in peripheral blood of children with asthma (P<0.001). Knockdown of lncRNA NEAT1 or GATA3 significantly reduced Th2-related cytokines (P<0.05), but had no effect on Th1 cells. Importantly, the interactions of lncRNA NEAT1 with miR-217 and miR-217 with GATA3 were confirmed by dual luciferase report assay. Meanwhile, functional assays and animal experiments demonstrated that lncRNA NEAT1 regulated GATA3 expression through sponge miR-217, thereby regulating Th1/Th2 balance in CD4+T cells in pediatric asthma.

Conclusion

lncRNA NEAT1/miR-217/GATA3 axis may reveal the immunological mechanism of pediatric asthma, which has potential clinical application value in the future.

The role of PGE2 and EP receptors on lung's immune and structural cells; possibilities for future asthma therapy

Asthma is the most common airway chronic disease with treatments aimed mainly to control the symptoms. Adrenergic receptor agonists, corticosteroids and anti-leukotrienes have been used for decades, and the development of more targeted asthma treatments, known as biological therapies, were only recently established. However, due to the complexity of asthma and the limited efficacy as well as the side effects of available treatments, there is an urgent need for a new generation of asthma therapies. The anti-inflammatory and bronchodilatory effects of prostaglandin E2 in asthma are promising, yet complicated by undesirable side effects, such as cough and airway irritation. In this review, we summarize the most important literature on the role of all four E prostanoid (EP) receptors on the lung's immune and structural cells to further dissect the relevance of EP2/EP4 receptors as potential targets for future asthma therapy.

MiR-493-5p inhibits Th9 cell differentiation in allergic asthma by targeting FOXO1

The role of micro RNAs (miRNAs) in asthma remains unclear. In this study, we examined the role of miRNA in targeting FOXO1 in asthma. Results showed that miR-493-5p was one of the differentially expressed miRNAs in the PBMCs of asthmatic children, and was also associated with Th cell differentiation. The miR-493-5p expression decreased significantly in the OVA-induced asthma mice than the control groups. The miR-493-5p mimic inhibited the expression of the IL-9, IRF4 and FOXO1, while the inhibitor restored these effects. Moreover, the Dual-Luciferase analysis results showed FOXO1 as a novel valid target of miR-493-5p. According to the rescue experiment, miR-493-5p inhibited Th9 cell differentiation by targeting FOXO1. Then the exosomes in association with the pathogenesis of asthma was identified. Various inflammatory cells implicated in asthmatic processes including B and T lymphocytes, DCs, mast cells, and epithelial cells can release exosomes. Our results demonstrated that the DC-derived exosomes can inhibit Th9 cell differentiation through miR-493-5p, thus DC-derived exosomal miR-493-5p/FOXO1/Th9 may serve as a potential therapeutic target in the development of asthma.

Sanzi Yangqin Decoction Alleviates Allergic Asthma by Modulating Th1/Th2 Balance: Coupling Network Pharmacology with Biochemical Pharmacology

This study aimed to verify that Sanzi Yangqin Decoction (SYD) can relieve asthma in mice and explore the effect on TH1/Th2 balance. The targets of SYD and asthma were explored from the public database using various methods. The potential targets and signaling pathways were identified by KEGG enrichment analysis from DAVID database. Mice asthma models were established using OVA and aluminum hydroxide. Lung tissues of mice were stained with HE and Masson. The contents of IFN-γ, IL-4, and TNF-α in BALF and IgE in mouse serum were detected using ELISA. In addition, the changes in Th1 and Th2 cells of the spleen were detected by flow cytometry. Fourteen core targets including IL4, IFNG, and MMP9 were identified for the treatment of asthma by SYD. The content of IL-4 in the lung tissue and BALF was gradually decreased with the increase in SYD concentration, while the IFN-γ was gradually increased. The drug significantly reduced IgE levels in serum and TNF-α in BALF. The number of Th1 cells in the spleen increased, while Th2 cells decreased in a concentration-dependent manner. SYD can alleviate pulmonary inflammation, restore Th1/Th2 balance, and relieve asthma.

Nonylphenol exacerbates ovalbumin-induced allergic rhinitis via the TSLP-TSLPR/IL-7R pathway and JAK1/2-STAT3 signaling in a mouse model

Nonylphenol (NP) can be widely used as a plasticizer, surfactant, antioxidant, textile printing, dyeing additive, and pesticide emulsifier. Animal studies have shown that NP aggravates ovalbumin (OVA)-induced allergic rhinitis (AR); however, the exact mechanism underlying its action has not yet been detailed. This study aimed to explore the aggravation of the AR inflammatory response following NP exposure and its possible mechanism. The AR mouse model was constructed using OVA. Under NP exposure, allergic nasal symptoms were observed, eosinophil infiltration was assessed by Sirius red staining, and the levels of IL-4, IL-5, and IL-13 in nasal mucosa samples were detected using cytometric bead array. The mRNA levels of OX40/OX40L and GATA3 in nasal mucosa were detected by qPCR, and the expression levels of the TSLP and JAK1/2-STAT3 signaling pathway components were also identified. Our results suggest that NP exposure exacerbated allergic nasal symptoms and that eosinophils accumulated in nasal mucosa after OVA challenge. The levels of the typical T helper 2 cytokines, as well as the mRNA levels of OX40/OX40L and GATA3, were elevated in the nasal mucosa of OVA-challenged mice exposed to NP. In addition, NP exposure elevated the TSLP, TSLPR, IL-7R, p-JAK1, p-JAK2, and p-STAT3 levels in the nasal mucosa after OVA stimulation. Overall, the present study suggests NP can exacerbate OVA-induced AR inflammatory responses; furthermore, this aggravating effect of NP may be related to the TSLP-TSLPR/IL-7R and JAK1/2-STAT3 signaling pathways.

Immunological Effects of Aster yomena Callus-Derived Extracellular Vesicles as Potential Therapeutic Agents against Allergic Asthma

Plant-derived extracellular vesicles, (EVs), have recently gained attention as potential therapeutic candidates. However, the varying properties of plants that are dependent on their growth conditions, and the unsustainable production of plant-derived EVs hinder drug development. Herein, we analyzed the secondary metabolites of Aster yomena callus-derived EVs (AYC-EVs) obtained via plant tissue cultures and performed an immune functional assay to assess the potential therapeutic effects of AYC-EVs against inflammatory diseases. AYC-EVs, approximately 225 nm in size, were isolated using tangential flow filtration (TFF) and cushioned ultracentrifugation. Metabolomic analysis, using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS), revealed that AYC-EVs contained 17 major metabolites. AYC-EVs inhibited the phenotypic and functional maturation of LPS-treated dendritic cells (DCs). Furthermore, LPS-treated DCs exposed to AYC-EVs showed decreased immunostimulatory capacity during induction of CD4+ and CD8+ T-cell proliferation and activation. AYC-EVs inhibited T-cell reactions associated with the etiology of asthma in asthmatic mouse models and improved various symptoms of asthma. This regulatory effect of AYC-EVs resembled that of dexamethasone, which is currently used to treat inflammatory diseases. These results provide a foundation for the development of plant-derived therapeutic agents for the treatment of various inflammatory diseases, as well as providing an insight into the possible mechanisms of action of AYC-EVs.

Blockade of Tyrosine Kinase, LCK Leads to Reduction in Airway Inflammation through Regulation of Pulmonary Th2/Treg Balance and Oxidative Stress in Cockroach Extract-Induced Mouse Model of Allergic Asthma

Asthma is one of the most common inflammatory diseases affecting the airways. Approximately 300 million individuals suffer from asthma around the world. Allergic immune responses in the asthmatic airways are predominantly driven by Th2 cells and eosinophils. Lymphocyte-specific protein tyrosine kinase (LCK) is a non-receptor tyrosine kinase which regulates several key intracellular events through phosphorylation of its substrates. Some of the intracellular signaling pathways activated by LCK phosphorylation help in differentiation of Th2 cells which secrete allergic cytokines that amplify airway inflammation. Therefore, this investigative study was designed to determine the role of LCK in a cockroach extract (CE)-induced airway inflammation murine model of allergic asthma. Further, the effect of a pharmacological LCK inhibitor, A-770041, on allergic airway inflammation and key intracellular pathways in CD4+ T cells was assessed. Our data exhibit that there is an activation of LCK during allergic airway inflammation as depicted by increased p-LCK levels in CD4+ T cells. Activated LCK is involved in the activation of ITK, PLC-γ, GATA3, NFkB, and NFATc1. Activated LCK is also involved in the upregulation of Th2 related cytokines, such as IL-4/IL-5/IL-13 and oxidative stress, and the downregulation of Treg cells. Furthermore, utilization of LCK inhibitor causes the reduction in p-LCK, PLC-γ, GATA3, and NFATc1 as well as Th2 cytokines and oxidative stress. LCK inhibitor causes upregulation of Treg cells in allergic mice. LCK inhibitor also caused a reduction in CE-induced airway inflammation and mucus secretion. Therefore, the inhibition of LCK signaling could be a fruitful approach to adjust allergic airway inflammation through the attuning of Th2/Treg immune responses. This study could lead to the design of newer treatment options for better management of allergic inflammation in asthma.

Contribution of circulatory cells to asthma exacerbations and lung tissue-resident CD4 T cell memory

Tissue-resident memory CD4 T cells (Trm) are thought to be a major contributor to asthma relapse, but the role of circulatory T cells in asthma exacerbations or to maintaining the population of lung Trm cells is not fully understood. Here, we used a house dust mite allergen-based murine model of asthma relapse, and monitored the development of lung effector/Trm phenotype CD44hiCD62LloCD69+ CD4 T cells. To determine the contribution of circulatory cells, mice were treated with FTY720, to block lymphocyte egress from lymph nodes. Inhibiting the primary migration of circulatory cells to the lungs mitigated the accumulation and expansion of allergen-driven Trm phenotype cells, but subsequent allergen challenges still resulted in strong lung inflammation and Trm cell accumulation. This was blocked if FTY720 was also given at the time of allergen re-exposure, showing that new circulatory cells contributed to this lung memory/effector T cell pool at times well after the initial sensitization. However, once lung-localized Trm cells developed at high frequency, circulatory cells were not required to maintain this population following allergen re-encounter, even though circulatory cells still were major contributors to the overall asthmatic lung inflammatory response. Our results suggest that strategies that target the response of circulatory memory T cells and Trm cells together might be required to strongly inhibit T cell reactivity to airborne allergens and to limit exacerbations of asthma and their reoccurrence, but the contribution of circulatory T cells might vary in long-term asthmatics possessing a large stable Trm cell population in the lungs.

IL-23 plays a significant role in the augmentation of particulate matter-mediated allergic airway inflammation

It has been recently that particulate matter (PM) exposure increases the risk and exacerbation of allergic asthma. However, the underlying mechanisms and factors associated with increased allergic responses remain elusive. We evaluated IL-23 and IL-23R (receptor) expression, as well as changes in the asthmatic phenotype in mice administered PM and a low dose of house dust mite (HDM). Next, changes in the phenotype and immune responses were evaluated after intranasal administration of anti-IL-23 antibody during co-exposure to PM and low-dose HDM. We also performed in vitro experiments to investigate the effect of IL-23. IL-23 expression was significantly increased in Epcam+CD45- and CD11c+ cells, while that of IL-23R was increased in Epcam+CD45- cells only in mice administered PM and low-dose HDM. Administration of anti-IL-23 antibody led to decreased airway hyperresponsiveness, eosinophils, and activation of dendritic cells, reduced populations of Th2 Th17, ILC2, the level of IL-33 and granulocyte-macrophage colony-stimulating factor (GM-CSF). Inhibition of IL-23 in PM and low-dose HDM stimulated airway epithelial cell line resulted in decreased IL-33, GM-CSF and affected ILC2 and the activation of BMDCs. PM augmented the phenotypes and immunologic responses of asthma even at low doses of HDM. Interestingly, IL-23 affected immunological changes in airway epithelial cells.

Prenatal exposure to air pollution and the risk of eczema in childhood: a systematic review and meta-analysis

An increasing number of studies investigated the association between air pollution during pregnancy and the risk of eczema in offspring. However, no meta-analysis has confirmed the existence and size of their association to date. We systematically searched PubMed, Web of Science, Cochrane Library, and Embase databases to select the observational controlled studies published from the inception date to October 16, 2021. Quality evaluation was guided by the Newcastle-Ottawa Scale (NOS). Sensitivity analysis was applied to assess the impact of each included study on the combined effects, and publication bias was examined by Begg's tests and Egger's tests. A total of 12 articles involving 69,374 participants met our eligibility criteria. A significant association between the maternal exposure to NO₂ (per 10 μg/m³ increased) and childhood eczema was observed, with a pooled risk estimate of 1.13 (95% CI: 1.06-1.19), but no association was observed between exposure to PM₁₀, PM_2.5, and SO₂ and the risk of eczema in offspring. Besides, the effect of maternal NO₂ exposure on childhood eczema was significant in the first and second trimesters, but not in the third trimester. There was notable variability in geographic location (p = 0.037) and air pollutant concentration (p = 0.031) based on meta-regression. Our findings indicated that prenatal exposure to NO₂ was a risk factor for elevated risk of eczema in childhood, especially in the first and second trimesters. Further studies with larger sample sizes considering different constituents of air pollution and various exposure windows are needed to validate these associations.

Livin promotes Th2-type immune response in airway allergic diseases

Objectives

To investigate the effects of livin on the Th2 immune response in airway allergic diseases (AAD) and explore the interaction among livin, GATA3, IL-4 in peripheral blood CD4⁺ T cells of AAD patients.

Methods

WT mice and livin KO mice were developed for model of AAD. Th2 cell levels in the lung tissues and spleen were assessed by flow cytometry. Also, it was assessed in the culture after exposing to livin inhibitor (Lp-15); the protein and mRNA levels of livin, GATA3 and IL-4 in peripheral blood CD4⁺ T cells isolated from patients with or without AAD were measured by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. Finally, Co-immunoprecipitation (Co-IP) was employed to identify the interaction between livin and GATA3.

Results

Compared with WT mouse, Th2 cell frequency in lung tissues and spleen was significantly decreased in livin KO mouse; after adding Lp-15, the differentiation from Naive CD4⁺T cells in spleen to Th2 cells was blocked; the protein and mRNA levels of livin, GATA3 and IL-4 in AAD group were higher than that in control group. The levels of livin were positively correlated with IL-4, and GATA3 was also positively correlated with IL-4 and livin. GATA3 was detected in the protein complex co-precipitated with livin antibody, and livin was also detected in the protein complex co-precipitated by GATA3 antibody.

Conclusion

Livin increases the expression of IL-4 and facilitates naive CD4⁺ T cells to differentiate into Th2 cells, which triggers airway allergy.

The Role of Autophagy in the Function of CD4+ T Cells and the Development of Chronic Inflammatory Diseases

Uncontrolled acute inflammation progresses to persistent inflammation that leads to various chronic inflammatory diseases, including asthma, Crohn’s disease, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus. CD4⁺ T cells are key immune cells that determine the development of these chronic inflammatory diseases. CD4⁺ T cells orchestrate adaptive immune responses by producing cytokines and effector molecules. These functional roles of T cells vary depending on the surrounding inflammatory or anatomical environment. Autophagy is an important process that can regulate the function of CD4⁺ T cells. By lysosomal degradation of cytoplasmic materials, autophagy mediates CD4⁺ T cell-mediated immune responses, including cytokine production, proliferation, and differentiation. Furthermore, through canonical processes involving autophagy machinery, autophagy also contributes to the development of chronic inflammatory diseases. Therefore, a targeted intervention of autophagy processes could be used to treat chronic inflammatory diseases. This review focuses on the role of autophagy via CD4⁺ T cells in the pathogenesis and treatment of such diseases. In particular, we explore the underlying mechanisms of autophagy in the regulation of CD4⁺ T cell metabolism, survival, development, proliferation, differentiation, and aging. Furthermore, we suggest that autophagy-mediated modulation of CD4⁺ T cells is a promising therapeutic target for treating chronic inflammatory diseases.

ICS/LABA Combined With Subcutaneous Immunotherapy Modulates the Th17/Treg Imbalance in Asthmatic Children

Rationale

The imbalance of T helper (Th17) cell and regulatory T (Treg) cell are involved in allergic asthma pathogenesis. We hypothesized that ICS/LABA could modulate the Th17/Treg imbalance and that subcutaneous immunotherapy (SCIT) could coordinate with ICS/LABA to rebalance the dysfunction of Th17/Treg.

Methods

Thirty house dust mites (HDM) allergic asthmatic children and fifteen healthy control subjects were enrolled in this study. Fifteen asthmatic children were treated by ICS/LABA powder inhalation, while the other fifteen asthmatic children were treated by ICS/LABA powder inhalation combined with HDM-SCIT. Asthmatic subjects were followed up for 6 months, but 2 asthmatics treated with ICS/LABA were lost to follow-up. Flow cytometry was used to determine the proportions of Th17 and Treg in CD4⁺ T cells from peripheral blood mononuclear cells (PBMCs). Serum levels of IL-17A and IL-10 were assessed by ELISA.

Result

ICS/LABA treatment significantly reduced the percentage of Th17 cells (1.252 ± 0.134% vs. 2.567 ± 0.386%), serum IL-17A (49.42 ± 2.643 pg/ml vs. 66.75 ± 3.442 pg/ml) and Th17/Treg ratio (0.194 ± 0.025 vs. 0.439 ± 0.072) compared to baseline (P<0.01). The ICS/LABA+HDM-SCIT treatment group showed similar reduction in the percentage of Th17 cells (1.11 ± 0.114% vs. 2.654 ± 0.276%), serum IL-17A (49.23 ± 2.131 pg/ml vs. 66.41 ± 2.616 pg/ml) and the Th17/Treg ratio (0.133 ± 0.015 vs. 0.4193 ± 0.050) (P<0.01). ICS/LABA+HDM-SCIT treatment group demonstrated elevated Treg percentages (8.483 ± 0.408% vs. 6.549 ± 0.299%) and serum IL-10 levels (127.4 ± 4.423 pg/ml vs. 93.15 ± 4.046 pg/ml), resulting in a lower Th17/Treg ratio than the ICS/LABA group.

Conclusion

ICS/LABA treatment regulates Th17/Treg imbalance mainly by mitigating Th17-induced inflammation in asthma patients. The addition of SCIT further enhanced such effect by upregulating Treg cells.

Gut microbiota of adults with asthma is broadly similar to non-asthmatics in a large population with varied ethnic origins

Bacterial gut communities might predispose children to develop asthma. Yet, little is known about the role of these micro-organisms in adult asthmatics. We aimed to profile the relationship between fecal microbiota and asthma in a large-scale, ethnically diverse, observational cohort of adults. Fecal microbiota composition of 1632 adults (172 asthmatics and 1460 non-asthmatics) was analyzed using 16S ribosomal RNA gene sequencing. Using extremely randomized trees machine learning models, we assessed the discriminatory ability of gut bacterial features to identify asthmatics from non-asthmatics. Asthma contributed 0.019% to interindividual dissimilarities in intestinal microbiota composition, which was not significant (P = .97). Asthmatics could not be distinguished from non-asthmatics based on individual microbiota composition by an extremely randomized trees classifier model (area under the receiver operating characteristic curve = 0.54). In conclusion, there were no prominent differences in fecal microbiota composition in adult asthmatics when compared to non-asthmatics in an urban, large-sized and ethnically diverse cohort.

HuR-Targeted Inhibition Impairs Th2 Proinflammatory Responses in Asthmatic CD4+ T Cells

RNA-binding protein HuR (ELAVL1) is a master regulator of gene expression in human pathophysiology. Its dysregulation plays an important role in many diseases. We hypothesized that HuR plays an important role in Th2 inflammation in asthma in both mouse and human. To address this, we used a model of airway inflammation in a T cell-specific knockout mouse model, distal lck-Cre HuR^fl/fl, as well as small molecule inhibitors in human peripheral blood-derived CD4⁺ T cells. Peripheral CD4⁺ T cells were isolated from 26 healthy control subjects and 45 asthmatics (36 type 2 high and 9 non-type 2 high, determined by blood eosinophil levels and fraction of exhaled NO). Our mouse data showed conditional ablation of HuR in T cell-abrogated Th2 differentiation, cytokine production, and lung inflammation. Studies using human T cells showed that HuR protein levels in CD4⁺ T cells were significantly higher in asthmatics compared with healthy control subjects. The expression and secretion of Th2 cytokines were significantly higher in asthmatics compared with control subjects. AMP-activated protein kinase activator treatment reduced the expression of several cytokines in both type 2 high and non-type 2 high asthma groups. However, the effects of CMLD-2 (a HuR-specific inhibitor) were more specific to endotype-defining cytokines in type 2 high asthmatics. Taken together, these data suggest that HuR plays a permissive role in both allergen and non-allergen-driven airway inflammation by regulating key genes, and that interfering with its function may be a novel method of asthma treatment.

Maggot extracts promote regulatory T cell differentiation by upregulating Foxp3 in allergic rhinitis

BACKGROUND AND OBJECTIVE

Maggots are the larval stage of Lucilia sericata and have strong antibacterial activity and immunomodulatory effects. The objective of our study was to investigate whether maggot extracts can modulate regulatory T cells (Tregs) and treat allergic rhinitis (AR).

METHODS

Mice were randomly assigned to five groups (n=6/group): normal, AR, Maggot, AR+ Maggot, and AR+ dexamethasone (DXM). The Total Nasal Symptom Score (TNSS), ovalbumin (OVA)-sIgE titers, histopathological characteristics and Th1-/Th2-/Th17-related cytokine levels were evaluated. The expression of T-bet, GATA3, RORγt and Foxp3 in the spleen and nasal mucosa of mice was detected, and the proportion of differentiated Tregs in the spleen of mice was determined. In addition, the effects of maggot extracts on the expression level of Foxp3 and the differentiation of Tregs in vitro were studied. Histological evaluation of the potential toxicity was also performed.

RESULTS

Compared with the AR group, the AR+ Maggot group showed reduction in histopathological inflammation, downregulated OVA-sIgE titers, and restoration of the imbalance in cytokine profiles (P<0.05). After treatment with maggot extracts, the proportions of Tregs and Foxp3 expression in the spleen were significantly increased, the expression of GATA3 and RORγt was decreased (P<0.05), and the expression of T-bet showed no significant change (P>0.05). In vitro, maggot extracts promoted the expression of Foxp3 and differentiation of Tregs in a dose- and time-dependent manner (P<0.05). In addition, no obvious organ damage was observed in mice treated with maggot extracts.

CONCLUSION

Maggot extracts can inhibit the progression of AR by upregulating the level of Foxp3 and promoting the differentiation of Tregs, thus serving as an alternate treatment for AR.

Asthma reduces glioma formation by T cell decorin-mediated inhibition of microglia

To elucidate the mechanisms underlying the reduced incidence of brain tumors in children with Neurofibromatosis type 1 (NF1) and asthma, we leverage Nf1 optic pathway glioma (Nf1^OPG) mice, human and mouse RNAseq data, and two different experimental asthma models. Following ovalbumin or house dust mite asthma induction at 4-6 weeks of age (WOA), Nf1^OPG mouse optic nerve volumes and proliferation are decreased at 12 and 24 WOA, indicating no tumor development. This inhibition is accompanied by reduced expression of the microglia-produced optic glioma mitogen, Ccl5. Human and murine T cell transcriptome analyses reveal that inhibition of microglia Ccl5 production results from increased T cell expression of decorin, which blocks Ccl4-mediated microglia Ccl5 expression through reduced microglia NFκB signaling. Decorin or NFκB inhibitor treatment of Nf1^OPG mice at 4-6 WOA inhibits tumor formation at 12 WOA, thus establishing a potential mechanistic etiology for the attenuated glioma incidence observed in children with asthma.

The Role of CD4+ T Cells and Microbiota in the Pathogenesis of Asthma

Asthma, a chronic respiratory disease involving variable airflow limitations, exhibits two phenotypes: eosinophilic and neutrophilic. The asthma phenotype must be considered because the prognosis and drug responsiveness of eosinophilic and neutrophilic asthma differ. CD4+ T cells are the main determinant of asthma phenotype. Th2, Th9 and Tfh cells mediate the development of eosinophilic asthma, whereas Th1 and Th17 cells mediate the development of neutrophilic asthma. Elucidating the biological roles of CD4+ T cells is thus essential for developing effective asthma treatments and predicting a patient's prognosis. Commensal bacteria also play a key role in the pathogenesis of asthma. Beneficial bacteria within the host act to suppress asthma, whereas harmful bacteria exacerbate asthma. Recent literature indicates that imbalances between beneficial and harmful bacteria affect the differentiation of CD4+ T cells, leading to the development of asthma. Correcting bacterial imbalances using probiotics reportedly improves asthma symptoms. In this review, we investigate the effects of crosstalk between the microbiota and CD4+ T cells on the development of asthma.

SJMHE1 Peptide from Schistosoma japonicum Inhibits Asthma in Mice by Regulating Th17/Treg Cell Balance via miR-155

Purpose

Helminths and their products can regulate immune response and offer new strategies to control and alleviate inflammation, including asthma. We previously found that a peptide named as SJMHE1 from Schistosoma japonicum can suppress asthma in mice. This study mainly investigated the molecular mechanism of SJMHE1 in inhibiting asthma inflammation.

Methods

SJMHE1 was administered to mice with OVA-induced asthma via subcutaneous injection, and its effects were detected by testing the airway inflammation of mice. The Th cell distribution was analyzed by flow cytometry. Th-related transcription factor and cytokine expression in the lungs of mice were analyzed using quantitative real-time PCR (qRT-PCR). The expression of miR-155 and levels of phosphorylated STAT3 and STAT5 were also determined after SJMHE1 treatment in mice by qRT-PCR and Western blot analysis. The in vitro mouse CD4⁺ T cells were transfected with lentivirus containing overexpressed or inhibited miR-155, and the proportion of Th17, Treg cells, CD4⁺p-STAT3⁺, and CD4⁺p-STAT5⁺ cells were analyzed by flow cytometry.

Results

SJMHE1 ameliorated the airway inflammation of asthmatic mice, upregulated the proportion of Th1 and Treg cells, and the expression of Th1 and Treg-related transcription factor and cytokines. Simultaneously, SJMHE1 treatment reduced the percentage of Th2 and Th17 cells and the expression of Th2 and Th17-related transcription factor and cytokines. SJMHE1 treatment decreased the expression of miR-155 and p-STAT3 but increased p-STAT5 expression. In vitro, the percentage of Th17 and CD4⁺p-STAT3⁺ cells increased in CD4⁺ T cells transfected over-expression of miR-155, but SJMHE1 inhibited the miR-155-mediated increase of Th17 cells. Furthermore, SJMHE1 increased the proportion of Treg and CD4⁺p-STAT5⁺ cells after transfected over-expression or inhibition of miR-155.

Conclusion

SJMHE1 regulated the balance of Th17 and Treg cells by modulating the activation of STAT3 and STAT5 via miR-155 in asthma. SJMHE1 might be a promising treatment for asthma.

Dexamethasone-Induced FKBP51 Expression in CD4+ T-Lymphocytes Is Uniquely Associated With Worse Asthma Control in Obese Children With Asthma

Introduction

There is evidence that obesity, a risk factor for asthma severity and morbidity, has a unique asthma phenotype which is less atopic and less responsive to inhaled corticosteroids (ICS). Peripheral blood mononuclear cells (PBMC) are important to the immunologic pathways of obese asthma and steroid resistance. However, the cellular source associated with steroid resistance has remained elusive. We compared the lymphocyte landscape among obese children with asthma to matched normal weight children with asthma and assessed relationship to asthma control.

Methods

High-dimensional flow cytometry of PBMC at baseline and after dexamethasone stimulation was performed to characterize lymphocyte subpopulations, T-lymphocyte polarization, proliferation (Ki-67+), and expression of the steroid-responsive protein FK506-binding protein 51 (FKBP51). T-lymphocyte populations were compared between obese and normal-weight participants, and an unbiased, unsupervised clustering analysis was performed. Differentially expressed clusters were compared with asthma control, adjusted for ICS and exhaled nitric oxide.

Results

In the obese population, there was an increased cluster of CD4+ T-lymphocytes expressing Ki-67 and FKBP51 at baseline and CD4+ T-lymphocytes expressing FKBP51 after dexamethasone stimulation. CD4+ Ki-67 and FKBP51 expression at baseline showed no association with asthma control. Dexamethasone-induced CD4+ FKBP51 expression was associated with worse asthma control in obese participants with asthma. FKBP51 expression in CD8+ T cells and CD19+ B cells did not differ among groups, nor did polarization profiles for Th1, Th2, Th9, or Th17 percentage.

Discussion

Dexamethasone-induced CD4+ FKBP51 expression is uniquely associated with worse asthma control in obese children with asthma and may underlie the corticosteroid resistance observed in this population.

Differential Regulation of Interferon Signaling Pathways in CD4+ T Cells of the Low Type-2 Obesity-Associated Asthma Phenotype

In the era of personalized medicine, insights into the molecular mechanisms that differentially contribute to disease phenotypes, such as asthma phenotypes including obesity-associated asthma, are urgently needed. Peripheral blood was drawn from 10 obese, non-atopic asthmatic adults with a high body mass index (BMI; 36.67 ± 6.90); 10 non-obese, non-atopic asthmatic adults with normal BMI (23.88 ± 2.73); and 10 healthy controls with normal BMI (23.62 ± 3.74). All asthmatic patients were considered to represent a low type-2 asthma phenotype according to selective clinical parameters. RNA sequencing (RNA-Seq) was conducted on peripheral blood CD4⁺ T cells. Thousands of differentially expressed genes were identified in both asthma groups compared with heathy controls. The expression of interferon (IFN)-stimulated genes associated with IFN-related signaling pathways was specifically affected in obese asthmatics, while the gap junction and G protein-coupled receptor (GPCR) ligand binding pathways were enriched in both asthma groups. Furthermore, obesity gene markers were also upregulated in CD4⁺ T cells from obese asthmatics compared with the two other groups. Additionally, the enriched genes of the three abovementioned pathways showed a unique correlation pattern with various laboratory and clinical parameters. The specific activation of IFN-related signaling and viral infection pathways might provide a novel view of the molecular mechanisms associated with the development of the low type-2 obesity-associated asthma phenotype, which is a step ahead in the development of new stratified therapeutic approaches.

Dectin-1 Controls TSLP-Induced Th2 Response by Regulating STAT3, STAT6, and p50-RelB Activities in Dendritic Cells

The epithelium-associated cytokine thymic stromal lymphopoietin (TSLP) can induce OX40L and CCL17 expression by myeloid dendritic cells (mDCs), which contributes to aberrant Th2-type immune responses. Herein, we report that such TSLP-induced Th2-type immune response can be effectively controlled by Dectin-1, a C-type lectin receptor expressed by mDCs. Dectin-1 stimulation induced STAT3 activation and decreased the transcriptional activity of p50-RelB, both of which resulted in reduced OX40L expression on TSLP-activated mDCs. Dectin-1 stimulation also suppressed TSLP-induced STAT6 activation, resulting in decreased expression of the Th2 chemoattractant CCL17. We further demonstrated that Dectin-1 activation was capable of suppressing ragweed allergen (Amb a 1)-specific Th2-type T cell response in allergy patients ex vivo and house dust mite allergen (Der p 1)-specific IgE response in non-human primates in vivo. Collectively, this study provides a molecular explanation of Dectin-1-mediated suppression of Th2-type inflammatory responses and suggests Dectin-1 as a target for controlling Th2-type inflammation.

Platycodin D attenuates airway inflammation via suppression Th2 transcription factor in a murine model of acute asthma

Introduction: Bronchial asthma is a common chronic inflammatory condition of the airway tissue. Platycodin D (PLD) has antiinflammatory effects in a mouse model of allergic asthma. In this work, the anti-asthma potential of PLD was studied by investigation of its effect to suppress airway inflammation and mucin production, a murine model of asthma and the possible mechanisms.Methods: Mice were randomly assigned to five experimental groups: control, ovalbumin (OVA), OVA+ICS (intranasal fluticasone), OVA+PLD and OVA+PLD/ICS. Airway histological studies were evaluated by the H&E staining; IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid were evaluated by ELISA; GATA3 and IRF4 mRNA of airway were measured by RT-PCR and their protein level were measured by Western blotting.Results: Our study showed that PLD suppressed eosinophilic inflammation and mucin production in bronchial mucosa. Moreover, PLD inhibited production of Th2 cytokines such as IL-4, IL-5, and IL-13. Protein production of GATA3 and IRF4, were also decreased in PLD treated OVA asthma model. Taken together, our results provided evidence that PLD inhibits the airway inflammation via suppression of Th2 transcription factor production.Conclusion: These findings suggest that PLD may effectively ameliorate the progression of asthma. These results suggest that PLD could be used as a therapy for allergic asthma.

Perfluorooctanesulfonate and perfluorooctanoate exacerbate airway inflammation in asthmatic mice and in vitro

Emerging evidence suggests associations between Perfluoroalkyl substances (PFASs) exposure and asthma, but the findings are inconsistent. The current study sought to investigate whether perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) could contribute to asthma exacerbation and to clarify the underlying biological mechanisms. The objectives are a) to determine whether PFOS or PFOA could aggravate the mouse asthma and pulmonary inflammation b) to investigate whether PFOS and PFOA regulate the balance of Th1/Th2 through the JAK-STAT signaling pathway and aggravated asthma. Ovalbumin (OVA) induced asthmatic mice were exposed to PFOS or PFOA by gavage. PFOS and PFOA serum level and toxicity in organs were assessed; and the impacts on respiratory symptoms, lung tissue pathology, T helper cell (Th2) response, and STAT6 pathway activity were also evaluated. In vitro Jurkat cells were used to study the mechanisms of PFOS and PFOA mediated Th1 and Th2 responses. Both PFOS and PFOA exacerbated lung tissue inflammation (greater number of eosinophils and mucus hyperproduction), upregulated Th2 cytokine production (IL-4 and IL-13), and promoted Th2 cells and STAT6 activation. Furthermore, PFOS and PFOA enhanced the Th2 response in Jurkat cells via STAT6 activation; and the effect of PFOS exposure on GATA-3, IL-4 and IFN-γ was blocked after the expression of STAT6 was suppressed in Jurkat cells, however, the effects of PFOA exposure were only partially blocked. PFOS and PFOA aggravated inflammation among OVA-induced asthmatic mice, by promoting the Th2 response in lymphocytes and disturbing the balance of Th1/Th2 through the JAK-STAT signaling pathway.

Single-cell transcriptomic analysis of allergen-specific T cells in allergy and asthma

CD4⁺ T helper (T_H) cells and regulatory T (T_reg) cells that respond to common allergens play an important role in driving and dampening airway inflammation in patients with asthma. Until recently, direct, unbiased molecular analysis of allergen-reactive T_H and T_reg cells has not been possible. To better understand the diversity of these T cell subsets in allergy and asthma, we analyzed the single-cell transcriptome of ~50,000 house dust mite (HDM) allergen-reactive T_H cells and T_reg cells from asthmatics with HDM allergy and from three control groups: asthmatics without HDM allergy and nonasthmatics with and without HDM allergy. Our analyses show that HDM allergen-reactive T_H and T_reg cells are highly heterogeneous and certain subsets are quantitatively and qualitatively different in individuals with HDM-reactive asthma. The number of interleukin-9 (IL-9)-expressing HDM-reactive T_H cells is greater in asthmatics with HDM allergy compared with nonasthmatics with HDM allergy, and this IL-9-expressing T_H subset displays enhanced pathogenic properties. More HDM-reactive T_H and T_reg cells expressing the interferon response signature (T_HIFNR and T_regIFNR) are present in asthmatics without HDM allergy compared with those with HDM allergy. In cells from these subsets (T_HIFNR and T_regIFNR), expression of TNFSF10 was enriched; its product, tumor necrosis factor-related apoptosis-inducing ligand, dampens activation of T_H cells. These findings suggest that the T_HIFNR and T_regIFNR subsets may dampen allergic responses, which may help explain why only some people develop T_H2 responses to nearly ubiquitous allergens.

Sophoricoside from Sophora japonica ameliorates allergic asthma by preventing mast cell activation and CD4+ T cell differentiation in ovalbumin-induced mice

Asthma is a chronic inflammatory lung disorder with continuously increasing prevalence worldwide. Novel strategies are needed to prevent or improve asthma. The aim of this study was to investigate the effects of sophoricoside from Sophora japonica on allergic asthma. The mature seeds of S. japonica contain a large amount of sophoricoside. Sophoricoside reduced allergic and asthmatic symptoms by suppressing airway inflammation and antibody-antigen reaction in mouse models. In particular, sophoricoside suppressed immune cell recruitment into the airway lumens of the lungs and production of pro-inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) of ovalbumin (OVA)-induced mice. It also decreased the amounts of histamine and arachidonic acid metabolites released in OVA-induced mice and antibody-antigen stimulated mast cells. In addition, sophoricoside decreased differentiation of naïve CD4+ T cells into T helper type 1 (Th1), Th2, and Th17 cells. Overall, we demonstrated that sophoricoside improved allergic asthma by suppressing mast cell activation and CD4+ T cell differentiation.

Fms-Like Tyrosine Kinase 3-Independent Dendritic Cells Are Major Mediators of Th2 Immune Responses in Allergen-Induced Asthmatic Mice

Dendritic cells (DCs) are the main mediators of Th2 immune responses in allergic asthma, and Fms-like tyrosine kinase 3 ligand (Flt3L) is an important growth factor for the development and homeostasis of DCs. This study identified the DC populations that primarily cause the initiation and development of allergic lung inflammation using Fms-like tyrosine kinase 3 (Flt3) knockout (KO) mice with allergen-induced allergic asthma. We observed type 2 allergic lung inflammation with goblet cell hyperplasia in Flt3 KO mice, despite a significant reduction in total DCs, particularly CD103⁺ DCs, which was barely detected. In addition, bone marrow-derived dendritic cells (BMDCs) from Flt3 KO mice directed Th2 immune responses in vitro, and the adoptive transfer of these BMDCs exacerbated allergic asthma with more marked Th2 responses than that of BMDCs from wild-type (WT) mice. Furthermore, we found that Flt3L regulated the in vitro expression of OX40 ligand (OX40L) in DCs, which is correlated with DC phenotype in in vivo models. In conclusion, we revealed that Flt3-independent CD11b⁺ DCs direct Th2 responses with the elevated OX40L and are the primary cause of allergic asthma. Our findings suggest that Flt3 is required to control type 2 allergic inflammation.

Regulatory B cells control airway hyperreactivity and lung remodeling in a murine asthma model

BACKGROUND

Asthma is a widespread, multifactorial chronic airway disease. The influence of regulatory B cells on airway hyperreactivity (AHR) and remodeling in asthma is poorly understood.

OBJECTIVE

Our aim was to analyze the role of B cells in a house dust mite (HDM)-based murine asthma model.

METHODS

The influence of B cells on lung function, tissue remodeling, and the immune response were analyzed by using wild-type and B-cell-deficient (μMT) mice and transfer of IL-10-proficient and IL-10-deficient B cells to μMT mice.

RESULTS

After HDM-sensitization, both wild-type and μMT mice developed AHR, but the AHR was significantly stronger in μMT mice, as confirmed by 2 independent techniques: invasive lung function measurement in vivo and examination of precision-cut lung slices ex vivo. Moreover, airway remodeling was significantly increased in allergic μMT mice, as shown by enhanced collagen deposition in the airways, whereas the numbers of FoxP3⁺ and FoxP3^- IL-10-secreting regulatory T cells were reduced. Adoptive transfer of IL-10-proficient but not IL-10-deficient B cells into μMT mice before HDM-sensitization attenuated AHR and lung remodeling. In contrast, FoxP3⁺ regulatory T cells were equally upregulated by transfer of IL-10-proficient and IL-10-deficient B cells.

CONCLUSION

Our data in a murine asthma model illustrate a central role of regulatory B cells in the control of lung function and airway remodeling and may support future concepts for B-cell-targeted prevention and treatment strategies for allergic asthma.

Role of T cells in the pathogenesis and treatment of gout

Though macrophages and neutrophils are considered to be the principal immune cells involved in gout inflammation, recent studies highlight an emerging role of T cell subsets in the pathogenesis of gout. Some studies found that abnormal functions of several T cell subsets and aberrant expressions of their signature cytokines existed in gouty arthritis. Additionally, recent studies also suggested that therapeutic strategies by targeting pro-inflammatory T cell subsets or their related cytokines could ameliorate monosodium urate (MSU) crystals-induced arthritis in mice. The important role of T cells in gouty arthritis may provide some explanation for the absence of acute gout attacks among individuals with severe hyperuricemia or clinical evidence of MSU crystals deposition. Nevertheless, the molecular mechanisms underlying the role of those T cell subsets in gouty arthritis and their role in the initiation, progression and resolution of gouty arthritis are largely elusive, which need to be elaborated in future research. Uncovering the role of those T cell subsets in gout may transform our understanding of gout and facilitate new promising preventive or therapeutic strategies for gouty arthritis.