Regulatory T cells mediated immunomodulation during asthma: a therapeutic standpoint

Interleukin-38-overexpressing adenovirus infection in dendritic cell-based treatment enhances immunotherapy for allergic asthma via inducing Foxp3+ regulatory T cells

Allergic asthma is a chronic disease tied to unusual immune reactions involving type 2 T helper (Th2) cells specific to allergens. Dendritic cells (DCs) play a crucial role in guiding T-cell responses. Regulatory T (Treg) cells have the ability to suppress effector T-cell responses, and interleukin (IL)-38 is involved in Treg cell differentiation. In this study, we explored impacts of IL-38 on the activation and function of DCs, and we then developed an IL-38-overexpressing adenovirus (Ad-IL38) to evaluate its effectiveness in treating allergic asthma in mice through the adaptive transfer of Ad-IL38-infected DCs (IL38-DCs). Treating lipopolysaccharide (LPS)-activated bone marrow-derived DCs with recombinant IL-38 reduced cluster of differentiation 80 (CD80), CD86, and major histocompatibility complex (MHC) II expressions and decreased IL-1β, IL-6, and tumor necrosis factor (TNF)-α while increasing IL-10 secretion. The simultaneous culture of these semi-mature DCs with allogeneic CD4+ T cells facilitated the production of Forkhead box protein P3-positive (Foxp3+) Treg cells. A transcriptomic analysis revealed downregulation of the Chil3, Inhba, and Ctgf genes that are crucial for regulating inflammatory responses and cytokine-mediated signaling pathways in IL-38-treated DCs. In an animal model of asthma, IL38-DC treatment effectively decreased levels of an ovalbumin (OVA)-specific immunoglobulin E (IgE) antibody in serum, attenuated the severity of airway hyperresponsiveness, reduced the production of Th2-type cytokines (IL-4, IL-5, and IL-13) and proinflammatory cytokines (IL-6 and TNF-α) in bronchoalveolar lavage fluid, lowered expressions of the Th2-related cytokines IL-25 and thymic stromal-derived lymphopoietin (TSLP) by lung epithelial cells, and mitigated airway inflammation. Notably, enhanced expression of Foxp3+ Treg cells was linked to increased mRNA levels of transforming growth factor (TGF)-β production in vivo. In conclusion, we comprehensively clarified the immunomodulatory effects of IL-38 on DCs and provide a new treatment with IL-38 genetically modified DCs for alleviating Th2-mediated allergic diseases.

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.

The Immunosuppressive Functions of Eosinophils Are Compromised in Patients With Allergic Rhinitis, Particularly Concerning Rab27a Expression

BACKGROUND

Eosinophils have been acknowledged to be involved in the induction of numerous inflammatory disorders. There is still a lack of knowledge about whether eosinophils play a role in immune regulation. The aim of this study is to uncover the immune regulatory functions of eosinophils.

METHODS

Blood samples were collected from patients with allergic rhinitis (AR) and healthy control subjects. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples. Eosinophils were purified from PBMCs using flow cytometry cell sorting and analyzed using immunological approaches.

RESULTS

The results showed that eosinophils from healthy subjects had immune regulatory functions on T cell proliferation and cytokine release. Impairment of eosinophil immune regulatory functions was found in AR patients, which was associated with AR responses. Elevated Rab27a expression in eosinophils was associated with their impaired immune regulatory functions and the increased AR responses. Rab27a controlled the release of mediators from eosinophils. Low concentrations of Eosinophil mediators could trigger immune regulatory responses, while high concentrations could trigger inflammatory responses. Regulating Rab27a restored the immune regulatory functions of eosinophils of AR patients.

CONCLUSIONS

Eosinophils have immune regulatory functions, which are controlled by the expression of Rab27a. Regulation of Rab27a can improve the immune regulatory functions of eosinophils. The data suggest that inhibition of Rab27a can be a drug candidate for the treatment of eosinophil-related disorders.

Mitigation of allergic asthma in mice: A compound mixture comprising luteolin, arbutin, and marmesin from Gerbera Piloselloides Herba by suppression of PI3K/Akt pathway

Background

Gerberae Piloselloidis Herba (GPH) exhibits notable efficacy in alleviating allergic asthma. Previous studies in our research have identified a mixture of luteolin, arbutin, and marmesin as effective components of GPH in treating allergic asthma. However, the underlying mechanism remains unclear. This study aims to elucidate the molecular mechanism of these active components.

Method

Using an ovalbumin (OVA)-induced allergic asthma mouse model, various treatment groups were administered, including GPH, the active component mixture (termed "Mixture") containing luteolin, arbutin, and marmesin, and a positive drug (dexamethasone, DEX). Relevant indices were assessed, including behavioral characteristics, inflammatory cell counts, cytokine levels, histopathological examination of lung tissue, apoptosis, and expression of key proteins such as Caspase-3, Bax, Bcl-2, PI3K, p-PI3K, Akt, and p-Akt. The effect of the Mixture on the PI3K/Akt signaling pathway was further verified using the PI3K inhibitor LY294002.

Results

The Mixture significantly alleviated asthma symptoms, decreased IgE levels, cytokine levels (IL-4, IL-5, IL-13 and TNF-α), and the number of inflammatory cells in serum or bronchoalveolar lavage fluid (BALF), leading to the alleviation of lung pathological lesions. Additionally, the Mixture reduced the expression of Bax and Caspase-3 while increasing Bcl-2 expression, resulting in mitigated apoptosis in lung tissue. Furthermore, there appeared a decrease in the levels of PI3K and p-PI3K, as well as the ratio of p-Akt to Akt in the Mixture group, indicating the suppression of PI3K and Akt phosphorylation. Interestingly, the effects of the Mixture were comparable to those of GPH, LY294002, or the combination of LY294002 with the Mixture.

Conclusion

The study confirms that the Mixture containing luteolin, arbutin, and marmesin indeed alleviates allergic asthma induced by OVA in mice by suppressing the PI3K/Akt signaling pathway. These findings highlight the potential of the GPH-derived Mixture as a novel therapeutic for the treatment of allergic asthma.

Intranasal Immunization of Pneumococcal pep27 Mutant Attenuates Allergic and Inflammatory Diseases by Upregulating Skin and Mucosal Tregs

Conventional immunization methods such as intramuscular injections lack effective mucosal protection against pathogens that enter through the mucosal surfaces. Moreover, conventional therapy often leads to adverse events and compromised immunity, followed by complicated outcomes, leading to the need to switch to other options. Thus, a need to develop safe and effective treatment with long-term beneficial outcomes to reduce the risk of relapse is mandatory. Mucosal vaccines administered across mucosal surfaces, such as the respiratory or intestinal mucosa, to prompt robust localized and systemic immune responses to prevent the public from acquiring pathogenic diseases. Mucosal immunity contains a unique immune cell milieu that selectively identify pathogens and limits the transmission and progression of mucosal diseases, such as allergic dermatitis and inflammatory bowel disease (IBD). It also offers protection from localized infection at the site of entry, enables the clearance of pathogens on mucosal surfaces, and leads to the induction of long-term immunity with the ability to shape regulatory responses. Regulatory T (Treg) cells have been a promising strategy to suppress mucosal diseases. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Nasal immunization protects mucosal surfaces, but nasal antigen presentation appears to entail the need for an adjuvant to stimulate immunogenicity. Here, a novel method is developed to induce Tregs via intranasal immunization without an adjuvant to potentially overcome allergic diseases and gut and lung inflammation using lung-gut axis communication in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies on Treg resilience through clinical translational studies on dietary changes.

Pathogenic role of different phenotypes of immune cells in airway allergic diseases: a study based on Mendelian randomization

Background

Airway allergic disease (AAD) is a class of autoimmune diseases with predominantly Th2-type inflammation, mainly including allergic rhinitis (AR), allergic asthma (AS), and chronic sinusitis (CRS). There are very complex regulatory mechanisms between immune cells and AAD; however, previous reports found that the functions of the same immune cells in AAD are not identical.

Objective

The aim of this study was to explore the causal relationship between different phenotypic immune cells and their association with AAD.

Method

Utilizing the publicly available Genome-Wide Association Studies (GWAS) database, this study conducted a bidirectional Mendelian randomization (MR) to assess the causal relationship between immune cells of 731 different immunophenotypes and AAD. The primary assessment methods included inverse variance weighting, weighted median, and MR Egger. Additionally, sensitivity analyses such as MR-PRESSO, leave-one-out, and scatter plots were employed to eliminate the interference of heterogeneity and pleiotropy, ensuring the stability of the causal inference.

Result

A total of 38 immune cells with different immunophenotypes were found to be positively and causally associated with AR, of which 26 were protective factors and 12 were risk factors. Positive associations were found between 33 immune cells and AS, of which 14 were protective factors and 19 were risk factors, as well as between 39 immune cells and CRS, of which 22 were protective factors and 17 were risk factors. Finally, the results of all relevant immune cells for the three diseases were taken and intersected, and it was found that CD3 on CD39+-activated Treg (IVWAR = 0.001, IVWCRS = 0.043, IVWAS = 0.027) may be the key immune cell that inhibits the development of AAD (ORAR = 0.940, ORAS = 0.967, ORCRS = 0.976).

Conclusion

This study reveals that different immune phenotypes of immune cells are closely related to AAD at the genetic level, which provides a theoretical basis for future clinical studies.

Therapeutic approaches of cell therapy based on stem cells and terminally differentiated cells: Potential and effectiveness

Cell-based therapy, as a promising regenerative medicine approach, has been a promising and effective strategy to treat or even cure various kinds of diseases and conditions. Generally, two types of cells are used in cell therapy, the first is the stem cell, and the other is a fully differentiated cell. Initially, all cells in the body are derived from stem cells. Based on the capacity, potency and differentiation potential of stem cells, there are four types: totipotent (produces all somatic cells plus perinatal tissues), pluripotent (produces all somatic cells), multipotent (produces many types of cells), and unipotent (produces a particular type of cells). All non-totipotent stem cells can be used for cell therapy, depending on their potency and/or disease state/conditions. Adult fully differentiated cell is another cell type for cell therapy that is isolated from adult tissues or obtained following the differentiation of stem cells. The cells can then be transplanted back into the patient to replace damaged or malfunctioning cells, promote tissue repair, or enhance the targeted organ's overall function. With increasing science and knowledge in biology and medicine, different types of techniques have been developed to obtain efficient cells to use for therapeutic approaches. In this study, the potential and opportunity of use of all cell types, both stem cells and fully differentiated cells, are reviewed.

Plexin B1 controls Treg numbers, limits allergic airway inflammation, and regulates mucins

We investigated the effect of global Plexin B1 deficiency on allergic airway responses to house dust mite (HDM) or ovalbumin (OVA). In the HDM model, there were higher Th2 cytokine levels in the BALF of Plexin B1 knock-out (KO) mice compared to wild type (WT), and tissue inflammation and mucus production were modestly enhanced. In the OVA model, Plexin B1 deficiency led to increases in lung inflammation, mucus production, and lung Th2 cytokines accompanied by dysregulated mucin gene expression without affecting anti-OVA IgE/IgG1 levels. Spleen cells from Plexin B1 KO mice proliferated more robustly than WT cells in vitro to a variety of stimuli. Plexin B1 KO CD4+ T cells from spleens expressed higher levels of Ki-67 and CD69 compared to WT cells. Spleen cells from naïve Plexin B1 KO mice secreted increased amounts of IL-4 and IL-6 when pulsed in vitro with OVA whereas in vivo OVA-primed spleen cells produced IL-4/IL-5 when subjected to in vitro OVA restimulation. The upregulated allergic inflammatory response in Plexin B1 KO mice was associated with a lower number of Tregs in the lung tissues. Moreover, these mice displayed lower numbers of Treg cells in the lymphoid tissues at the baseline. These results demonstrate a previously unrecognized link between Plexin B1, Treg cells, and mucus in allergic lung inflammation.

Investigating Forkhead Box O Transcription Factor 1 Gene's Relation to Immunoglobulin E in House Dust Mite-Allergic Asthma Patients

House dust mite (HDM)-allergic asthma is an abnormal immune response to extrinsic aeroallergens found in human vicinities. Studying the role of the associated immunity biomarkers and their interplay helps in discovering novel therapeutic strategies that can be used in adjunct with effective long-term immunotherapy. This study investigates the total serum IgE, FoxO1, and Sirtuin 1 (SIRT1) gene expressions in HDM-allergic asthma patients. We enrolled 40 patients for each of the following three groups: an HV group of healthy volunteers and HDM/AA and HDM/SCIT groups of HDM-allergic asthma patients who did not and who did receive immunotherapy before recruitment in this study, respectively. The results elucidated that total IgE was strikingly elevated in the HDM/AA group and showed little decline in the HDM/SCIT group. Both FoxO1 and SIRT1 gene expressions showed the highest levels in the HDM/SCIT group. There was a negative correlation between total IgE and both FoxO1 and SIRT1 in the HDM/AA group while there was a positive correlation with SIRT1 in the HDM/SCIT group. In conclusion, the interplay of the three immunity biomarkers related to HDM-allergic asthma after the course of immunotherapy treatment suggests further, broader studies on the feasibility of their role as immunity biomarkers in the control and remission of HDM-allergic asthma.

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.

Regulatory T cells in allergic inflammation

Regulatory T (Treg) cells maintain immune tolerance to allergens at the environmental interfaces in the airways, skin and gut, marshalling in the process distinct immune regulatory circuits operative in the respective tissues. Treg cells are coordinately mobilized with allergic effector mechanisms in the context of a tissue-protective allergic inflammatory response against parasites, toxins and potentially harmful allergens, serving to both limit the inflammation and promote local tissue repair. Allergic diseases are associated with subverted Treg cell responses whereby a chronic allergic inflammatory environment can skew Treg cells toward pathogenic phenotypes that both perpetuate and aggravate disease. Interruption of Treg cell subversion in chronic allergic inflammatory conditions may thus provide novel therapeutic strategies by re-establishing effective immune regulation.

The effect of anti-IL5 monoclonal antibodies on regulatory and effector T cells in severe eosinophilic asthma

INTRODUCTION

Biological treatments have redesigned the clinical management of severe eosinophilic asthmatic (SA) patients. Despite emerging evidence supporting the role of natural Killer (NK), and T regulatory cells (Treg) in the pathogenesis of asthma, no data is available on the effects of anti-IL5/IL5R therapies on these cell subsets.

METHODS

We prospectively enrolled fourteen SA patients treated with benralizumab (n = 7) or mepolizumab (n = 7) and compared them with healthy controls (HC) (n = 11) and mild to moderate asthmatic (MM) patients (n = 9). Clinical parameters were collected at baseline (T0) and during follow-up. Cellular analysis, including the analysis of T/NK cell subsets, was determined through multicolor flow cytometry.

RESULTS

At T0, SA patients showed higher percentages of CD4 TEM (33.3 ± 17.9 HC, 42.6 ± 16.6 MM and 66.1 ± 19.7 in SA; p < 0.0001) than HC and MM patients. With different timing, the two drugs induce a reduction of CD4 TEM ( 76 ± 19 T0; 43 ± 14 T1; 45 ± 23 T6; 62 ± 18 at T24; p < 0.0001 for mepolizumab and 55 ± 21 T0; 55 ± 22 T1; 43 ± 14 T6; 27 ± 12 at T24; p < 0.0001 for benralizumab) and an increase of Treg cells (1.2 ± 1.3 T0; 5.1 ± 2.5 T1; 6.3 ± 3.4 T6; 8.4 ± 4.6 at T24; p < 0.0001 for mepolizumab and 3.4 ± 1.7 T0; 1.9 ± 0.8 T1; 1.9 ± 1 T6; 5.1 ± 2.4 at T24; p < 0.0001 for benralizumab). The change of CD56dim PD-1+ significantly correlated with FEV1% (r = - 0.32; p < 0.01), while Treg expressing PD-1 correlates with the use of oral steroids ( r = 0.36 p = 0.0008) and ACT score (r = 0.36 p = 0.0008) p < 0.001) CONCLUSIONS: Beyond the clinical improvement, anti-IL-5 treatment induces a rebalancing of Treg and T effector cells in patients with SA.

Monitoring regulatory T cells as a prognostic marker in lung transplantation

Lung transplantation is the major surgical procedure, which restores normal lung functioning and provides years of life for patients suffering from major lung diseases. Lung transplant recipients are at high risk of primary graft dysfunction, and chronic lung allograft dysfunction (CLAD) in the form of bronchiolitis obliterative syndrome (BOS). Regulatory T cell (Treg) suppresses effector cells and clinical studies have demonstrated that Treg levels are altered in transplanted lung during BOS progression as compared to normal lung. Here, we discuss levels of Tregs/FOXP3 gene expression as a crucial prognostic biomarker of lung functions during CLAD progression in clinical lung transplant recipients. The review will also discuss Treg mediated immune tolerance, tissue repair, and therapeutic strategies for achieving in-vivo Treg expansion, which will be a potential therapeutic option to reduce inflammation-mediated graft injuries, taper the toxic side effects of ongoing immunosuppressants, and improve lung transplant survival rates.

Norisoboldine exerts antiallergic effects on IgE/ovalbumin-induced allergic asthma and attenuates FcεRI-mediated mast cell activation

Allergic asthma is an inflammatory lung disorder, and mast cells play crucial roles in the development of this allergic disease. Norisoboldine (NOR), the major isoquinoline alkaloid present in Radix Linderae, has received considerable attention because it has anti-inflammatory effects. Herein, the aim of this study was to explore the antiallergic effects of NOR on allergic asthma in mice and mast cell activation. In a murine model of ovalbumin (OVA)-induced allergic asthma, oral administration at 5 mg/kg body weight (BW) of NOR produced strong reductions in serum OVA-specific immunoglobulin E (IgE) levels, airway hyperresponsiveness, and bronchoalveolar lavage fluid (BALF) eosinophilia, while an increase in CD4+Foxp3+ T cells of the spleen was detected. Histological studies demonstrated that NOR treatment significantly ameliorated the progression of airway inflammation including the recruitment of inflammatory cells and mucus production by decreasing levels of histamine, prostaglandin D2 (PGD2), interleukin (IL)-4, IL-5, IL-6, and IL-13 in BALF. Furthermore, our results revealed that NOR (3 ∼ 30 μM) dose-dependently reduced expression of the high-affinity receptor for IgE (FcεRI) and the production of PGD2 and inflammatory cytokines (IL-4, IL-6, IL-13, and TNF-α), and also decreased degranulation of bone marrow-derived mast cells (BMMCs) activated by IgE/OVA. In addition, a similar suppressive effect on BMMC activation was observed by inhibition of the FcεRI-mediated c-Jun N-terminal kinase (JNK) signaling pathway using SP600125, a selective JNK inhibitor. Collectively, these results suggest that NOR may have therapeutic potential for allergic asthma at least in part through regulating the degranulation and the release of mediators by mast cells.

Therapeutic effects of Pulsatilla koreana Nakai extract on ovalbumin-induced allergic rhinitis by inhibition of Th2 cell activation and differentiation via the IL-4/STAT6/GATA3 pathway

Allergic rhinitis (AR), caused by immunoglobulin E (IgE)-mediated inflammation, generally occurs in the upper respiratory tract. T helper type 2 (Th2) cell-mediated cytokines, including interleukin (IL)-4, IL-5, and IL-13, are important factors in AR pathogenesis. Despite various treatment options, the difficulty in alleviating AR and pharmacological side effects necessitate development of new therapies. The root of Pulsatilla koreana Nakai (P. koreana), a pasque flower, has been used as a herbal medicine. However, its effects on AR remain unclear; therefore, we aimed to explore this subject in the current study. The therapeutic effects of P. koreana water extract (PKN) on the pathophysiological functions of the nasal mucosa was examined in ovalbumin (OVA)-induced AR mice. The effect of PKN on Th2 activation and differentiation was evaluated using concanavalin A-induced splenocytes and differentiated Th2 cells from naïve CD4⁺ T cells. We also investigated the effect of changes in JAK/STAT6/GATA3 signaling on IL-4-induced Th2 cells. In OVA-induced AR mice, PKN administration alleviated allergic nasal symptoms and decreased the total number of immune cells, lymphocytes, neutrophils, and eosinophils in nasal lavage fluid; serum levels of OVA-specific IgE, histamine, and IL-13 were also significantly reduced. PKN also ameliorated OVA-induced nasal mucosal tissue thickening by inhibiting inflammation and goblet cell hyperplasia. PKN treatment significantly inhibited Th2 activity and differentiation through the IL-4/STAT-6/GATA3 pathway in Th2 cells. PKN is an effective AR treatment with the potential to improve patients' daily lives by regulating the allergic inflammatory response induced by Th2 cells.

Regulatory T-cells in asthma

PURPOSE OF REVIEW

This review addresses recent progress in our understanding of the role of regulatory T (Treg) cells in enforcing immune tolerance and tissue homeostasis in the lung at steady state and in directing the immune response in asthmatic lung inflammation.

RECENT FINDINGS

Regulatory T cells regulate the innate and adaptive immune responses at steady state to enforce immune tolerance in lung tissues at steady state and their control of the allergic inflammatory responses induced by allergens. This regulatory function can break down in the context of chronic asthmatic airway inflammation such that the lung tissue Treg cells become skewed towards a pathogenic phenotype that aggravates and perpetuates disease. Subversion of lung tissue Treg cell function involves their upregulation of Notch4 expression, which in turn acts to amplify T helper type 2 and type 17 and innate lymphoid cell type 2 responses in the airways.

SUMMARY

A dual role for Treg cells has emerged both as immune regulators but also a potential disease effectors in asthma, with implications for disease therapy.

The Effect of Environmental Factors on Immunological Pathways of Asthma in Children of the Polish Mother and Child Cohort Study

The FOXP3 transcription factor is a marker of regulatory T cells (Tregs), and is essential in the process of their activation and proper expression by promoting immune homeostasis. To assess the influence of the environment on the development of asthma, we hypothesized that in our cohort, exposure to environmental factors is associated with asthma risk in children, and that FOXP3 levels vary with their incidence and are negatively correlated with developing asthma. This prospective study conducted in Poland uses a cohort of 85 children (42 with and 43 without asthma diagnosis) aged 9 to 12 years recruited for the Polish Mother and Child Cohort Study. We collected questionnaires and organized visits to assess patients' clinical condition (skin prick tests, lung function assessments). Blood samples were taken to determine immune parameters. Breastfed children had lower risk of asthma. Asthma risk was higher in children who live in the city, with antibiotic course before the age of 2 and antibiotic therapy more than twice a year. Environmental factors were associated with childhood asthma. Breastfeeding, the coexistence of other allergic diseases, and the frequency of housekeeping affect FOXP3 levels, which are negatively correlated with the risk of asthma.

Interleukin-34-regulated T-cell responses in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease with a multifaceted etiology, which primarily affects and results in the deterioration of the synovium of patients. While the exact etiology of RA is still largely unknown, there is growing interest in the cytokine interleukin-34 (IL-34) as a driver or modulator of RA pathogenesis on the grounds that IL-34 is drastically increased in the serum and synovium of RA patients. Several studies have so far revealed the relationship between IL-34 levels and RA disease progression. Nevertheless, the significance and role of IL-34 in RA have remained ambiguous, as illustrated by two most recent studies, which reported contrasting effects of genetic IL-34 deletion in RA. Of note, IL-34 is a macrophage growth factor and is increasingly perceived as a master regulator of T-cell responses in RA via macrophage-dependent as well as T cell-intrinsic mechanisms. In this regard, several studies have demonstrated that IL-34 potentiates helper T-cell (Th) responses in RA, whereas studies also suggested that IL-34 alleviates synovial inflammation, potentially by inducing regulatory T-cells (Treg). Herein, we provide an overview of the current understanding of IL-34 involvement in RA and outline IL-34-mediated mechanisms in regulating T-cell responses in RA.

Research hotspot and frontier analysis of traditional Chinese medicine in asthma using bibliometric methods from 1991 to 2021

Traditional Chinese medicine (TCM) has been successfully used to treat asthmatic conditions for centuries. Nevertheless, the current hotspots and research frontiers on TCM for asthma have not been systematically investigated on the basis of bibliometric analysis. In this study, a scientometric analysis (1991-2021) was carried out on 3081 journal articles obtained from the Web of Science Core Collection database to explore the basic characteristics, research hotspots, and frontiers of TCM in asthma research. The results revealed the following: (1) Research on TCM in asthma has received widespread attention since the beginning of the 21st century; perhaps 2009 was an important turning point. TCM in asthma research shows a trend of interdisciplinary development. (2) Well-known universities/institutions in China, the United States, and South Korea have conducted the main body of current TCM research in asthma. JingCheng Dong (Fudan University, China) and XiuMin Li (Mount Sinai School of Medicine, USA) are the top 2 leading authors in this field. However, there is still a lack of international cooperation in the field of TCM in asthma research, and the influence of researchers in China and South Korea still needs improvement. (3) The Journal of Allergy and Clinical Immunology ranks first in the research field on the influence of TCM in asthma. (4) Hotspots and frontiers of TCM in asthma are provided according to the timeline analyses of the research. In the former, complementary medicine, alternative treatment, allergic rhinitis, airway remodeling, Dietary Approach to Stop Hypertension diet, and eosinophilic esophagitis are in the exploratory stage. In the latter, pharmacology, essential oil, gut microbiota, and oxidative stress were investigated from 2006 until late 2021 as period B, which contradicts period A (1991-2005). Moreover, limitations of this bibliometric analysis and the study of TCM research in asthma still exist, which are sufficiently important to warrant further investigations. Finally, we propose the significant importance of the real quintessence and characteristics of TCM in clinical and future research.

Identification of potential key genes for immune infiltration in childhood asthma by data mining and biological validation

Asthma is the most common chronic condition among children; however, the underlying molecular mechanism remains unclear. Dysregulated immune response and different infiltration states of immune cells are critical for asthma pathogenesis. Here, three childhood asthma gene expression datasets were used to detect key genes, immune cells, and pathways involved in childhood asthma. From these datasets, 33 common differentially expressed genes (DEGs) were identified, which showed enrichment in the T helper 1 (Th1) and T helper 2 (Th2) cell differentiation pathway and the T helper 17 (Th17) cell differentiation pathway. Using the weighted gene co-expression network analysis (WGCNA), CD3D and CD3G were identified as key genes closely correlated with childhood asthma. Upregulation of CD3D and CD3G was further validated in bronchoalveolar lavage cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The immune cell infiltration analysis indicated that CD3D and CD3G were negatively correlated with increased resting mast cells and eosinophils, and highly correlated with several cell markers of Th1, Th2, and Th17 cells. In addition, we found that CD3D and CD3G were closely related to the Th1 and Th2 cell differentiation pathway and the Th17 cell differentiation pathway. Our results reveal the important roles of two key genes and immune infiltration in the pathogenesis of childhood asthma. Thus, this study provides a new perspective for exploring potential molecular targets for childhood asthma treatment.

The Pioneer Transcription Factor Foxa2 Modulates T Helper Differentiation to Reduce Mouse Allergic Airway Disease

Foxa2, a member of the Forkhead box (Fox) family of transcription factors, plays an important role in the regulation of lung function and lung tissue homeostasis. FOXA2 expression is reduced in the lung and airways epithelium of asthmatic patients and in mice absence of Foxa2 from the lung epithelium contributes to airway inflammation and goblet cell hyperplasia. Here we demonstrate a novel role for Foxa2 in the regulation of T helper differentiation and investigate its impact on lung inflammation. Conditional deletion of Foxa2 from T-cells led to increased Th2 cytokine secretion and differentiation, but decreased Th1 differentiation and IFN-γ expression in vitro. Induction of mouse allergic airway inflammation resulted in more severe disease in the conditional Foxa2 knockout than in control mice, with increased cellular infiltration to the lung, characterized by the recruitment of eosinophils and basophils, increased mucus production and increased production of Th2 cytokines and serum IgE. Thus, these experiments suggest that Foxa2 expression in T-cells is required to protect against the Th2 inflammatory response in allergic airway inflammation and that Foxa2 is important in T-cells to maintain the balance of effector cell differentiation and function in the lung.

Sex Steroids Effects on Asthma: A Network Perspective of Immune and Airway Cells

A multitude of evidence has suggested the differential incidence, prevalence and severity of asthma between males and females. A compilation of recent literature recognized sex differences as a significant non-modifiable risk factor in asthma pathogenesis. Understanding the cellular and mechanistic basis of sex differences remains complex and the pivotal point of this ever elusive quest, which remains to be clarified in the current scenario. Sex steroids are an integral part of human development and evolution while also playing a critical role in the conditioning of the immune system and thereby influencing the function of peripheral organs. Classical perspectives suggest a pre-defined effect of sex steroids, generalizing estrogens popularly under the “estrogen paradox” due to conflicting reports associating estrogen with a pro- and anti-inflammatory role. On the other hand, androgens are classified as “anti-inflammatory,” serving a protective role in mitigating inflammation. Although considered mainstream and simplistic, this observation remains valid for numerous reasons, as elaborated in the current review. Women appear immune-favored with stronger and more responsive immune elements than men. However, the remarkable female predominance of diverse autoimmune and allergic diseases contradicts this observation suggesting that hormonal differences between the sexes might modulate the normal and dysfunctional regulation of the immune system. This review illustrates the potential relationship between key elements of the immune cell system and their interplay with sex steroids, relevant to structural cells in the pathophysiology of asthma and many other lung diseases. Here, we discuss established and emerging paradigms in the clarification of observed sex differences in asthma in the context of the immune system, which will deepen our understanding of asthma etiopathology.

Regulatory T Cells, a Viable Target Against Airway Allergic Inflammatory Responses in Asthma

Asthma is a multifactorial disorder characterized by the airway chronic inflammation, hyper-responsiveness (AHR), remodeling, and reversible obstruction. Although asthma is known as a heterogeneous group of diseases with various clinical manifestations, recent studies suggest that more than half of the clinical cases are ‘‘T helper type 2 (Th2)-high’’ type, whose pathogenesis is driven by Th2 responses to an inhaled allergen from the environmental exposures. The intensity and duration of inflammatory responses to inhaled allergens largely depend on the balance between effector and regulatory cells, but many questions regarding the mechanisms by which the relative magnitudes of these opposing forces are remained unanswered. Regulatory T cells (Tregs), which comprise diverse subtypes with suppressive function, have long been attracted extensive attention owing to their capability to limit the development and progression of allergic diseases. In this review we seek to update the recent advances that support an essential role for Tregs in the induction of allergen tolerance and attenuation of asthma progression once allergic airway inflammation established. We also discuss the current concepts about Treg induction and Treg-expressed mediators relevant to controlling asthma, and the therapies designed based on these novel insights against asthma in clinical settings.

MALT1 in asthma children: A potential biomarker for monitoring exacerbation risk and Th1/Th2 imbalance-mediated inflammation

BACKGROUND

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) participates in the immune-related allergic response and inflammation flare, while its clinical role in asthma children is still unknown. Herein, this study aimed to investigate MALT1 expression, and its correlation with exacerbation risk, T helper (Th)1, Th2 cells (and their secreted cytokines), as well as inflammatory cytokines in asthma children.

METHODS

Sixty children with asthma exacerbation and 60 children with remission asthma were enrolled in this study; then their blood MALT1, Th1, Th2 cells, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and interleukin-4 (IL-4) were detected. Besides, blood MALT1 in another 20 health controls was also determined.

RESULTS

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 was highest in children with asthma exacerbation, followed by children with remission asthma, and lowest in health controls (p < 0.001). MALT1 could distinguish children with asthma exacerbation from children with remission asthma (area under the curve (AUC): 0.757, 95% CI: 0.670-0.843). In children with asthma exacerbation, MALT1 was negatively linked with IFN-γ (p = 0.002) and Th1 cells (p = 0.050), but positively related to Th2 cells (p = 0.027) and exhibited a positive correlation trend (without statistical significance) with IL-4 (p = 0.066); meanwhile, MALT1 was positively correlated with exacerbation severity (p = 0.010) and TNF-α (p = 0.003), but not linked with IL-6 (p = 0.096). In children with remission asthma, MALT1 only was negatively associated with Th1 cells (p = 0.023), but positively linked with TNF-α (p = 0.023).

CONCLUSION

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 serves as a potential biomarker for monitoring exacerbation risk and Th1/Th2 imbalance-mediated inflammation of asthma children.

Immune Regulation of Heme Oxygenase-1 in Allergic Airway Inflammation

Heme oxygenase-1 (HO-1) is not only a rate-limiting enzyme in heme metabolism but is also regarded as a protective protein with an immunoregulation role in asthmatic airway inflammation. HO-1 exerts an anti-inflammation role in different stages of airway inflammation via regulating various immune cells, such as dendritic cells, mast cells, basophils, T cells, and macrophages. In addition, the immunoregulation role of HO-1 may differ according to subcellular locations.

Acteoside exerts immunomodulatory effects on dendritic cells via aryl hydrocarbon receptor activation and ameliorates Th2-mediated allergic asthma by inducing Foxp3+ regulatory T cells

Dendritic cells (DCs) are professional antigen-presenting cells that play a key role in directing T-cell responses and are involved in the pathogenesis of allergic asthma. Acteoside, an active phenylethanoid glycoside, is widely distributed in many medicinal plants. Herein, we explored the immunomodulatory effects of acteoside on bone marrow-derived DCs in vitro, and further investigated the immunosuppressive ability of acteoside to manipulate T helper type 2 (Th2)-mediated allergic asthma in mice. Following lipopolysaccharide activation, 50 μM of acteoside significantly reduced the production of proinflammatory mediators, including interleukin (IL)-12 and tumor necrosis factor (TNF)-α, whereas it enhanced secretion of the anti-inflammatory cytokine, IL-10, by DCs. However, these effects of acteoside on DCs were reversed by pretreatment with CH223191, an aryl hydrocarbon receptor (AhR) antagonist. Additionally, coculture of acteoside-treated DCs with CD4⁺ T cells promoted the generation of forkhead box P3-positive (Foxp3⁺) regulatory T cells (Tregs) via AhR activation. Using a murine asthma model, our results demonstrated that oral administration of 50 mg/kg of acteoside decreased levels of Th2-type cytokines, such as IL-4, IL-5, and IL-13, whereas the level of IL-10 and the frequency of CD4⁺Foxp3⁺ Tregs were augmented. Moreover, acteoside treatment markedly inhibited the elevated serum level of ovalbumin-specific immunoglobulin E, attenuated the development of airway hyperresponsiveness, and reduced inflammatory cell counts in bronchoalveolar lavage fluid. Additionally, histological results reveled that acteoside ameliorated pulmonary inflammation in asthmatic mice. Taken together, these results indicated that acteoside exhibits immunomodulatory effects on DCs and plays an anti-inflammatory role in the treatment of allergic asthma.

A census of the lung: CellCards from LungMAP

The human lung plays vital roles in respiration, host defense, and basic physiology. Recent technological advancements such as single-cell RNA sequencing and genetic lineage tracing have revealed novel cell types and enriched functional properties of existing cell types in lung. The time has come to take a new census. Initiated by members of the NHLBI-funded LungMAP Consortium and aided by experts in the lung biology community, we synthesized current data into a comprehensive and practical cellular census of the lung. Identities of cell types in the normal lung are captured in individual cell cards with delineation of function, markers, developmental lineages, heterogeneity, regenerative potential, disease links, and key experimental tools. This publication will serve as the starting point of a live, up-to-date guide for lung research at https://www.lungmap.net/cell-cards/. We hope that Lung CellCards will promote the community-wide effort to establish, maintain, and restore respiratory health.

Systemic Pharmacological Smoothened Inhibition Reduces Lung T-Cell Infiltration and Ameliorates Th2 Inflammation in a Mouse Model of Allergic Airway Disease

Allergic asthma is a common inflammatory airway disease in which Th2 immune response and inflammation are thought to be triggered by inhalation of environmental allergens. Many studies using mouse models and human tissues and genome-wide association have indicated that Sonic Hedgehog (Shh) and the Hedgehog (Hh) signaling pathway are involved in allergic asthma and that Shh is upregulated in the lung on disease induction. We used a papain-induced mouse model of allergic airway inflammation to investigate the impact of systemic pharmacological inhibition of the Hh signal transduction molecule smoothened on allergic airway disease induction and severity. Smoothened-inhibitor treatment reduced the induction of Shh, IL-4, and IL-13 in the lung and decreased serum IgE, as well as the expression of Smo, Il4, Il13, and the mucin gene Muc5ac in lung tissue. Smoothened inhibitor treatment reduced cellular infiltration of eosinophils, mast cells, basophils, and CD4+ T-cells to the lung, and eosinophils and CD4+ T-cells in the bronchoalveolar lavage. In the mediastinal lymph nodes, smoothened inhibitor treatment reduced the number of CD4+ T-cells, and the cell surface expression of Th2 markers ST2 and IL-4rα and expression of Th2 cytokines. Thus, overall pharmacological smoothened inhibition attenuated T-cell infiltration to the lung and Th2 function and reduced disease severity and inflammation in the airway.

Follicular T Helper and Breg Cell Balance in Severe Allergic Asthma Before and After Omalizumab Therapy

BACKGROUND

Severe allergic asthma (SAA) is based on type 2 (T2-high) immune responses to allergens promoting type 2 T helper (Th2) cell cytokine responses and production of IgE antibodies. Omalizumab was the first biological drug licensed for clinical use in the management of IgE-mediated SAA. Despite emerging evidence supporting the prominent role of follicular T cells (Tfh), Breg and Treg subsets, in the development and progression of SAA, no data are available on the impact of omalizumab therapy.

METHODS

Ten SAA patients monitored at the Respiratory Diseases Unit of Siena University Hospital and ten healthy sex- and age-matched controls were enrolled in the study. Clinical and functional parameters were collected at baseline (T0) and after 6 months of therapy (T6). Cellular population analysis was determined through multicolour flow cytometry.

RESULTS

SAA patients showed higher percentages of Th17.1, Tfh and Tfh2 while CD24hiCD27hi Breg cell, Treg and Tfr percentages were significantly lower than in controls. Higher percentages of Tfh2 in patients with nasal polyps than in those without and in controls were observed. At T6, significant decreases in Tfh and Tfh2 compared with T0 were observed. A slightly significant increase in Teffs was reported at T6 compared to T0. ΔIgE levels in serum were correlated with ΔCD19+CD24+CD27+ Breg cell percentages (r = - 0.86, p = 0.0022).

CONCLUSIONS

Our data explored the changes in Tfh cells, Tregs and Bregs in severe asthma. The restoration of immunological imbalance in SAA patients after omalizumab is certainly intriguing and represents a glimpse into the comprehension of immunological effects of treatment.

Allergen-Specific Treg Cells Upregulated by Lung-Stage S. japonicum Infection Alleviates Allergic Airway Inflammation

Schistosoma japonicum infection showed protective effects against allergic airway inflammation (AAI). However, controversial findings exist especially regarding the timing of the helminth infection and the underlying mechanisms. Most previous studies focused on understanding the preventive effect of S. japonicum infection on asthma (infection before allergen sensitization), whereas the protective effects of S. japonicum infection (allergen sensitization before infection) on asthma were rarely investigated. In this study, we investigated the protective effects of S. japonicum infection on AAI using a mouse model of OVA-induced asthma. To explore how the timing of S. japonicum infection influences its protective effect, the mice were percutaneously infected with cercaria of S. japonicum at either 1 day (infection at lung-stage during AAI) or 14 days before ovalbumin (OVA) challenge (infection at post–lung-stage during AAI). We found that lung-stage S. japonicum infection significantly ameliorated OVA-induced AAI, whereas post–lung-stage infection did not. Mechanistically, lung-stage S. japonicum infection significantly upregulated the frequency of regulatory T cells (Treg cells), especially OVA-specific Treg cells, in lung tissue, which negatively correlated with the level of OVA-specific immunoglobulin E (IgE). Depletion of Treg cells in vivo partially counteracted the protective effect of lung-stage S. japonicum infection on asthma. Furthermore, transcriptomic analysis of lung tissue showed that lung-stage S. japonicum infection during AAI shaped the microenvironment to favor Treg induction. In conclusion, our data showed that lung-stage S. japonicum infection could relieve OVA-induced asthma in a mouse model. The protective effect was mediated by the upregulated OVA-specific Treg cells, which suppressed IgE production. Our results may facilitate the discovery of a novel therapy for AAI.

Regulatory T cell monitoring in severe eosinophilic asthma patients treated with mepolizumab

Severe eosinophilic asthma (SEA) has been associated with T-helper type 2 (Th2) inflammatory response. A good understanding of T cell functions in asthma is important for therapy, especially in the choice of biological treatments for severe cases. Mepolizumab, an IL-5 antagonist, is indicated for the treatment of severe asthma. Regulatory T cells (Tregs) suppress inflammation by secreting cytokines that inhibit Th2 cell proliferation. We investigated peripheral Treg, CD4, CD8, CD19 and NK cell percentages and their relationship to clinical and functional parameters, including peripheral eosinophils, before and after anti-IL5 treatment. Subjects were 14 adult SEA patients (9 male, 54.1 ± 11.6 years), treated with mepolizumab, and 10 controls. T cells (CD4 and CD8), CD19, NK and Tregs were evaluated by flow cytometry. Comparison of lung function parameters before and after treatment with mepolizumab (T0 and T1) showed an increase in FEV1, FEV1/FVC ratio and a reduction in blood eosinophil percentages. CD8 and CD16/56⁺ CD3⁺ were significantly higher in SEA patients than controls (P = .04 and P = .03, respectively). A decrease in CD45+, CD8 + and CD16/56⁺ CD3⁺ cell percentages was observed between T0 and T1 (P = .02, P = .04, P = .03, respectively). A significant increase in Treg percentages (P = .0001) was recorded between T0 and T1. Mepolizumab therapy was found to modulate immune response, restoring immune balance in patients with SEA.