Pathogenesis Of Asthma Research Articles

The role of DC subgroups in the pathogenesis of asthma

Dendritic cells (DCs), specialized antigen-presenting cells of the immune system, act as immunomodulators in diseases of the immune system, including asthma. The understanding of DC biology has evolved over the years to include multiple subsets of DCs with distinct functions in the initiation and maintenance of asthma. Moreover, most strategies for treating asthma with relevant therapeutic agents that target DCs have been initiated from the study of DC function. We discussed the pathogenesis of asthma (including T2-high and T2-low), the roles played by different DC subpopulations in the pathogenesis of asthma, and the therapeutic strategies centered around DCs. This study will provide a scientific theoretical basis for current asthma treatment, provide theoretical guidance and research ideas for developing and studying therapeutic drugs targeting DC, and provide more therapeutic options for the patient population with poorly controlled asthma symptoms.

TRIM7 knockdown protects against LPS-induced autophagy, ferroptosis, and inflammatory responses in human bronchial epithelial cells.

Asthma is one of the most common respiratory diseases in pediatric department. Several asthma-associated events including inflammatory responses, autophagy, and ferroptosis have been identified as typical pathological processes. TRIM7 is a member of TRIM proteins family associated with several types of diseases. Nevertheless, its role in asthma is still elusive. The current research showed that TRIM7 was involved in the pathogenesis of asthma mainly by regulating the Akt signaling pathway. In detail, we found that TRIM7 was highly expressed in patients with asthma and in an in vitro model of asthma. The following analysis indicated that TRIM7 knockdown attenuated the expression and secretion of inflammatory cytokines including TNF-α, IL-1β and IL-6 in lipopolysaccharide (LPS)-exposed human bronchial epithelial cells (HBECs). Meanwhile, knockdown of TRIM7 exerted inhibitory effects on LPS-induced autophagy and ferroptosis. Further mechanistic studies showed that TRIM7 knockdown inhibited LPS-induced activation of Akt pathway, while overexpression of Akt attenuated the inhibitory effects of TRIM7 knockdown on LPS-exposed HBECs. Collectively, we reported here that TRIM7 knockdown inhibited LPS-induced autophagy, ferroptosis, and inflammatory cytokine secretion in HBECs via regulating the Akt pathway, providing a new insight into the strategies for improving asthma treatments.

Aging, brain-derived neurotrophic factor, and allergen-induced pulmonary responses in mice.

Asthma in the elderly is being recognized as more severe, resistant to standard therapies, and having greater morbidity. Therefore, it comes important to understand the impact of aging-associated airway structure and function changes towards pathogenesis of asthma in the elderly. Here, airway smooth muscle plays important roles in airway hyperreactivity and structural remodeling. The role of smooth muscle in asthma can be modulated by growth factors (including neurotrophins such as brain-derived neurotrophic factor (BDNF)) and pro-inflammatory senescence factors. In this study, we investigated aging effects on airway hyperreactivity, structural remodeling, inflammation, and senescence in a mouse model of allergic asthma. C57BL/6J wildtype mice or smooth muscle-specific BDNF knockout mice at 4, 18 and 24 months of age were intranasally exposed to mixed allergens (ovalbumin, aspergillus, Alternaria, and house dust mite) over 4 weeks. Assessing lung function by FlexiVent, we found that compared with 4 month old mice, 18 and 24 month old C57BL/6J mice showed decreased airway resistance and increased airway compliance after PBS or MA treatment. Deletion of smooth muscle BDNF blunted airway hyperreactivity in aged mice. Lung histology analysis revealed that aging increased bronchial airway thickness and decreased lung inflammation. Multiplex assays showed that aging largely reduced allergen-induced lung expression of proinflammatory chemokines and cytokines. By immunohistochemistry staining, we found that aging increased bronchial airway expression of senescence markers, including p21, phospho-p53 and phospho-gH2A.X. Our data suggest that aging associated increase of airway senescence in the context of allergen exposure may contribute to asthma pathology in the elderly.

Increased expression of Cathepsin C in airway epithelia exacerbates airway remodeling in asthma.

Airway remodeling is a critical factor determining the pathogenesis and treatment sensitivity of severe asthma (SA) or uncontrolled asthma (UA). The activation of epithelial-mesenchymal trophic units (EMTUs) regulated by airway epithelial cells (AECs) has been proven to induce airway remodeling directly. However, the triggers for EMTU activation and the underlying mechanism of airway remodeling are not fully elucidated. Here, we screened the differentially expressed gene Cathepsin C (CTSC)/dipeptidyl peptidase 1 (DPP-1) in epithelia of SA and UA patients using RNA sequencing data and further verified the increased expression of CTSC in induced sputum of asthma patients which was positively correlated with the severity and airway remodeling. Moreover, direct instillation of exogenous CTSC induced airway remodeling. Genetic inhibition of CTSC suppressed EMTU activation and airway remodeling in two asthma models with airway remodeling. Mechanistically, increased secretion of CTSC from AECs induced EMTU activation through p38-mediated pathway, further inducing airway remodeling. Meanwhile, inhibition of CTSC also reduced the infiltration of inflammatory cells and the production of inflammatory factors in the lungs of asthmatic mice. Consequently, targeting CTSC with compound AZD7986 protected against airway inflammation, EMTU activation and remodeling in asthma model. Based on the dual effects of CTSC on airway inflammation and remodeling, CTSC is a potential biomarker and therapeutic target for SA or UA.

Role of Thymic Stromal Lymphopoietin in the Pathophysiology of Asthma and Clinical and Biological Effects of Blockade With Tezepelumab.

The airway epithelium is the first line of defense of the respiratory system against the external environment. It plays an active role in the initiation of immune and allergic responses against potential hazards. Among the various specialized cells and cytokines that participate in epithelium-induced responses, alarmins are particularly interesting, given their ample role in mediating T2 and non-T2 inflammatory mechanisms involved in the pathogenesis of asthma. Thymic stromal lymphopoietin (TSLP) is an alarmin with broad effects in asthma that result from its widespread action on multiple cell types, including eosinophils, mast cells, dendritic cells, and group-2 innate lymphoid cells. Its role in allergy-mediated responses, eosinophilic inflammation, airway hyperresponsiveness, mucus hyperproduction, viral tolerance, and airway remodeling is of the utmost importance, as more comprehensive asthma assessments have been developed to explore these pathogenic features. Therefore, blockade with targeting molecules, such as monoclonal antibodies, has emerged as a promising therapeutic option, particularly in patients with multiple pathogenic pathways. In this review, we examine the roles of alarmins (mainly TSLP) in the pathogenesis of asthma and clinical expression and discuss the effects of inhibiting TSLP on several inflammatory and clinical outcomes. We also review the literature supporting treatment with anti-TSLP biologics and the unanswered questions and unmet needs associated with targeting alarmins in asthma.

High-CBD Extract (CBD-X) in Asthma Management: Reducing Th2-Driven Cytokine Secretion and Neutrophil/Eosinophil Activity.

Asthma is a chronic inflammatory disorder of the airways affecting over 10% of the global population. It is characterized by airway inflammation, mucus hypersecretion, and bronchial hyperresponsiveness, driven predominantly by type 2 helper T cells (Th2) and type 2 innate lymphoid cells (ILC2s) in a subset of patients. However, a significant portion of asthmatic individuals present with "type 2-low" asthma that is often refractory to standard inhaled corticosteroid (ICS) therapy. Therefore, developing innovative therapeutic strategies has become essential. Recent studies have highlighted cannabidiol (CBD) as a promising anti-inflammatory agent capable of modulating immune responses. This study investigates the therapeutic potential of a high-CBD extract (CBD-X) in asthma. We evaluated the effects of CBD-X on cells involved in asthma pathogenesis using primary human Th2 cells, neutrophils, and asthma mouse model. Our findings indicate that CBD-X extract inhibits Th2 differentiation and reduces the secretion of IL-5 and IL-13, which are crucial cytokines in asthma. Additionally, CBD-X significantly reduces pro-inflammatory cytokines IL-8 and IL-6 in neutrophils and impairs their migration, a critical step in airway inflammation. In a murine asthma model, CBD-X administration led to marked downregulation of IgE and pro-asthmatic cytokines, along with reduced leukocyte, eosinophil, and neutrophil infiltration in lung tissues. These results suggest that CBD-X extract could offer a novel and complementary approach to managing both type 2-high and type 2-low asthma by targeting key inflammatory pathways and modulating immune cell behavior.

Use of Targeted Biologic Therapies in Asthma: Current Practice in India

Asthma remains a significant public health issue in India, with a growing number of patients experiencing severe and uncontrolled forms of the disease. Targeted biologic therapies, including omalizumab, mepolizumab, benralizumab, reslizumab, and dupilumab, have emerged as advanced treatment options for patients with severe asthma, especially those with allergic or eosinophilic phenotypes. These therapies work by targeting specific immunological pathways involved in asthma pathogenesis, offering better symptom control and reducing exacerbation rates. However, the high cost of biologics, limited access, and inconsistent insurance coverage pose significant barriers to their widespread use in India. Despite these challenges, real-world data from Indian studies demonstrate promising clinical outcomes with biologic therapies in patients with difficult-to-treat asthma. This review examines the current landscape of biologic use in India, challenges related to cost and accessibility, and future prospects for integrating these treatments into routine asthma care, particularly through cost- reduction strategies and expanded healthcare coverage.

Innate players in Th2 and non-Th2 asthma - emerging roles for the epithelial cell, mast cell and monocyte/macrophage network.

Asthma is one of the most common chronic respiratory diseases and is characterized by airway inflammation, increased mucus production and structural changes in the airways. Recently, there is increasing evidence that the disease is much more heterogeneous than expected, with several distinct asthma endotypes. Based on the specificity of T cells as the best-known driving force in airway inflammation, bronchial asthma is categorized into T helper cell (Th)2 and non-Th2 asthma. The most studied effector cells in Th2 asthma include T cells and eosinophils. In contrast to Th2 asthma, much less is known about the pathophysiology of non-Th2 asthma, which is often associated with treatment resistance. Besides T cells, the interaction of myeloid cells such as monocytes/macrophages and mast cells with the airway epithelium significantly contributes to the pathogenesis of asthma. However, the underlying molecular regulation and particularly the specific relevance of this cellular network in certain asthma endotypes remains to be understood. In this review, we summarize recent findings on the regulation of and complex interplay between epithelial cells and the "non-classical" innate effector cells, mast cells and monocytes/macrophages, in Th2 and non-Th2 asthma with the ultimate goal to provide the rationale for future research into targeted therapy regimens.

Regulation of Airway Epithelial-Derived Alarmins in Asthma: Perspectives for Therapeutic Targets.

Asthma is a chronic respiratory condition predominantly driven by a type 2 immune response. Epithelial-derived alarmins such as thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 orchestrate the activation of downstream Th2 cells and group 2 innate lymphoid cells (ILC2s), along with other immune effector cells. While these alarmins are produced in response to inhaled triggers, such as allergens, respiratory pathogens or particulate matter, disproportionate alarmin production by airway epithelial cells can lead to asthma exacerbations. With alarmins produced upstream of the type 2 inflammatory cascade, understanding the pathways by which these alarmins are regulated and expressed is critical to further explore new therapeutics for the treatment of asthmatic patients. This review emphasizes the critical role of airway epithelium and epithelial-derived alarmins in asthma pathogenesis and highlights the potential of targeting alarmins as a promising therapeutic to improve outcomes for asthma patients.

Traditional Chinese medicine to improve immune imbalance of asthma: focus on the adjustment of gut microbiota.

Asthma, being the prevailing respiratory ailment globally, remains enigmatic in terms of its pathogenesis. In recent times, the advancement of traditional Chinese medicine pertaining to the intestinal microbiota has yielded a plethora of investigations, which have substantiated the potential of traditional Chinese medicine in disease prevention and treatment through modulation of the intestinal microbiota. Both animal models and clinical trials have unequivocally demonstrated the indispensable role of the intestinal microbiota in the pathogenesis of asthma. This article presents a summary of the therapeutic effects of traditional Chinese medicine in the context of regulating gut microbiota and its metabolites, thereby achieving immune regulation and inhibiting airway inflammation associated with asthma. It elucidates the mechanism by which traditional Chinese medicine modulates the gut microbiota to enhance asthma management, offering a scientific foundation for the utilization of traditional Chinese medicine in the treatment of asthma.

Characterisation of C-C Ligand 7 (CCL7) as Asthma Genetic Marker in Pigtailed Monkey.

The pigtailed monkey (Macaca nemestrina) is one of the species that have potency like the cynomolgus monkey that is widely used as an animal model for asthma study. The CCL7 gene has potential as a genetic marker because of the secreted chemokine that plays a role in asthma. The aims of this research are to characterise the CCL7 gene of pigtailed monkey, compare the structure of their CCL7 gene with other primate species and determine model 3D structure protein prediction of CCL7 protein. The amplicons were sequenced, and the results were analysed by the bioinformatics technique. The 3D CCL7 protein structure was predicted using I-TASSER. We have isolated 2221 bp sequences CCL7 gene and 109 amino acids from pigtailed monkey. Variation of CCL7 gene sequence between pigtailed monkey and other primate species (Macaca fascicularis, M. mulatta and Homo sapiens) was found in exon 1, exon 2 and exon 3 as CDS (Coding DNA Sequence) region. The analysis homology of nucleotides and amino acid sequences of the CCL7 gene indicated that the pigtailed monkey and three other primate species have a high homology rate with an identity score above 90%. Meanwhile, a comparative analysis of CDS and amino acid regions showed that the pigtailed monkey also has the highest similarity with the three other primate species with more than 90% identity score. The 3D structure protein prediction model of the CCL7 pigtailed monkey revealed the highest similarity with H. sapiens with an identity value of about 95%. Therefore, the pigtailed monkey CCL7 gene has high similarity with H. sapiens, which means that based on molecular similarity, the pigtailed monkey has the potential to be an animal model for asthma study, especially the study of molecular and the role of CCL7 in asthma pathogenesis.

CD226 implicated in Akt-dependent apoptosis of CD4+ T cell contributes to asthmatic pathogenesis.

Asthma is a chronic airway inflammatory disease in which CD4+ T cell dysregulation occurs. Here, we investigated the molecular role and clinical significance of CD226, a costimulatory molecule of T lymphocytes, in the development of allergic asthma. Our results revealed that the expression of CD226 was significantly increased in CD4+ effector T cells, especially in T helper (Th) 2 cells and Th17 cells in patients with asthma. Moreover, CD4+ T cell-specific Cd226-knockout mice were generated and together with littermates were challenged with ovalbumin (OVA) to establish a model of allergic asthma. We found that CD226 deficiency in CD4+ T cells mitigated lung inflammation, IgE production, and eosinophil infiltration and reduced airway remodeling in experimental allergic asthma. However, the impact of CD226 on asthma was independent of Treg cell modulation. Through RNA-seq data analysis, the apoptosis pathway was screened. Mechanistically, CD226 deletion promoted CD4+ T cell late apoptosis via the activation of Caspase-3 in an Akt-dependent manner. Furthermore, blocking CD226 signaling with a recombinant fusion protein attenuated asthma features in mice and achieved a good therapeutic effect. Overall, this study revealed a unique role of CD226 in CD4+ T cell regulation in asthma pathogenesis. Therefore, targeting CD226 may provide new insights into the clinical treatment of asthma.

Dynamic responses of human lung innate and adaptive immune cells highlight the roles of genes at asthma risk loci.

The lung is a unique immunological niche with diverse immune cell types. The effects of stimulation through innate and adaptive immune receptors on human lung immune cells has largely been extrapolated from studies of blood immune cells. While multiple immune cell types and many genes have been implicated as contributing to asthma, the dynamics of these in human lung immune cells following activation will yield insights into asthma pathogenesis and lung immunity more broadly. Human lung immune cells from 6 donors were isolated. Mixed leukocytes were treated separately with lipopolysaccharide (LPS), F(ab)2-anti-human-IgM/IgG + IL4 and anti-CD3/CD28 for 4 and 18 hours and underwent single cell RNA sequencing (scRNAseq). Lung immune cell types were annotated, and gene expression compared across conditions. Genes at prior asthma-associated genetic loci were characterized across cell types, treatments and timepoints. Expression of non-classical class II genes associated with asthma, HLA-DQA2 and HLA-DQB2, and their protein products was characterized with immunohistochemistry. We characterized gene expression in 116,697 lung immune cells. Cell-, treatment-, and timepoint-specific effects on gene expression were detected in all lung immune cell populations. Correlation of gene expression between lung and blood lymphocyte populations decreased following stimulation. Among the genes that were differentially expressed, 97 receptor:ligand pairs had changes with treatments. 96.0% of genes at asthma risk loci demonstrated differential expression in at least one cell type and at least one treatment. B cells were the cell type with the highest expression of HLA-DQA2 and HLA-DQB2 which increased with anti-IgM/IgG treatment and the HLA-DQB2 protein was identified in lung B cells from a donor with asthma. Human lung immune activation elicits a broad range of cellular responses that deviate from those of blood immune cells and are relevant to asthma. Lung B cells expressing HLA-DQA2 and HLA-DQB2 appear to be involved in a novel antigen presentation pathway that contributes to asthma risk.

DNA methylation-mediated FGFR1 silencing enhances NF-κB signaling: implications for asthma pathogenesis.

Fibroblast growth factor receptor 1 (FGFR1) is known to play a crucial role in the pathogenesis of asthma, although the precise mechanism remains unclear. This study aims to investigate how DNA methylation-mediated silencing of FGFR1 contributes to the enhancement of NF-κB signaling, thereby influencing the progression of asthma. RT-qPCR was utilized to assess FGFR1 mRNA levels in the serum of asthma patients and BEAS-2B, HBEpiC, and PCS-301-011 cells. CCK8 assays were conducted to evaluate the impact of FGFR1 overexpression on the proliferation of BEAS-2B, PCS-301-011, and HBEpiC cells. Dual-luciferase and DNA methylation inhibition assays were performed to elucidate the underlying mechanism of FGFR1 gene in asthma. The MassARRAY technique was employed to measure the methylation levels of the FGFR1 DNA. Elevated FGFR1 mRNA levels were observed in the serum of asthma patients compared to healthy controls. Overexpression of FGFR1 in BEAS-2B cells significantly enhanced cell proliferation and stimulated NF-ĸB transcriptional activity in HERK-293T cells. Furthermore, treatment with 5-Aza-CdR, a DNA demethylating agent, markedly increased the expression of FGFR1 mRNA in BEAS-2B, PCS-301-011, and HBEpiC cells. Luciferase activity analysis confirmed heightened NF-ĸB transcriptional activity in FGFR1-overexpressing BEAS-2B cells and BEAS-2B cells treated with 5-Aza-CdR. Additionally, a decrease in methylation levels in the FGFR1 DNA promoter was detected in the serum of asthma patients using the MassARRAY technique. Our findings reveal a potential mechanism involving FGFR1 in the progression of asthma. DNA methylation of FGFR1 inactivates the NF-ĸB signaling pathway, suggesting a promising avenue for developing effective therapeutic strategies for asthma.

Different allergen-induced asthma and anaphylaxis show distinctive IgE pathway dependence

BackgroundThe pathogenesis of allergic asthma is classically understood to involve allergens crosslinking Immunoglobulin E (IgE) bound to mast cells, leading to the release of histamine and other inflammatory mediators. ObjectiveThis study aims to explore whether different allergens have distinct IgE-dependent mechanisms in mouse models of both asthma and anaphylaxis. MethodsWild type (WT) and IgE knockout (IgE KO) mice were used to generate asthma mouse models. Lung inflammation was assessed by histological analysis and inflammatory cells in Bronchial Alveolar Lavage Fluids (BALF). Passive Cutaneous Anaphylaxis (PCA) was conducted to quantify IgE, and Toluidine Blue staining was used to visualize mast cell recruitment. ResultsAll allergen-treated mice exhibited significant airway inflammation. Compared to WT mice, HDM-treated IgE KO mice showed an attenuated inflammatory profile, particularly with reduced eosinophils. These mice had lower serum levels of HDM-specific IgE and IgG1 as well as reduced levels of Th2 cytokines interleukin 4 (IL-4) and IL-5 in BALF. CRE-treated IgE KO mice also displayed a reduced inflammation, with significant differences only in eosinophils. Interestingly, no significant differences in airway inflammation were observed between OVA-treated IgE KO mice and WT mice. Furthermore, both HDM and CRE-induced PCA model showed significantly less Evan's blue dye leakage and mast cell recruitment in the ears of IgE KO mice compared to WT mice, with no differences for OVA-induced PCA and mast cell recruitment. ConclusionThe results highlight the variability in IgE pathway dependence among different allergens, emphasizing the need for further research to delineate the underlying mechanisms.

Ciliary Function, Antigen Stasis and Asthma.

The prevalence of asthma exceeds 3% of the population. Asthma is observed to be more common in children following severe viral lower respiratory illnesses that affect ciliary function, but mechanisms linking ciliary function to asthma pathogenesis have been obscure. Recent data regarding primary ciliary dyskinesia (PCD) may help us to understand the association. Here, I will review what is known about the relationship between ciliary function and asthma. PCD is caused by pathologic variants in over 50 different genes that affect the structure and function of motile cilia. At the cellular level, a characteristic feature shared by most PCD patients is that antigens and other particles are not cleared from the epithelial surface. Poor antigen clearance results in pro-oxidant pathway activation and airway epithelial damage and may predispose PCD patients to DUOX1- and IL33-mediated asthma. Secondary ciliary dysfunction, such as that caused by viruses or by smoking, can also contribute to asthma development. Moreover, variants in genes that affect the function of cilia can be associated with poor lung function, even in the absence of PCD, and with increased asthma severity. The role of antigen stasis on the surface of dysfunctional airway cilia in the pathophysiology of asthma is a novel area for research, because specific airway clearance techniques and other therapeutic interventions, such as antioxidants, could be of value in preventing the development of asthma.

The Role of Hydroxyeicosatetraenoic Acids in the Regulation of Inflammation in Bronchial Asthma.

Hydroperoxyeicosatetraenoic acids (HETEs) are metabolites of arachidonic acid that are oxidized by a family of enzymes including cyclooxygenase, lipoxygenase, and cytochrome P450 enzymes. These enzymes are widely present in various organs and tissues, and the HETEs they synthesize perform an important function in the regulation of immune reactions and haemostasis processes under physiological and pathophysiological conditions. More researchers confirm the role of these oxidized metabolites in modulating inflammation in asthma. The high production of HETEs in allergic and severe asthma indicates their involvement in the processes of an acute inflammatory response. On the other hand, disturbance of the metabolic transformation of arachidonic acid contributes to the development of chronic inflammation due to insufficient synthesis of mediators that resolve inflammatory processes. Several HETEs have both pro-inflammatory and anti-inflammatory effects, which underscores the ongoing interest in their involvement in the pathogenesis of asthma. At the same time, research results are scarce. Based on an analysis of the literature, the pathways of metabolic transformation of 5-HETE, 12-HETE, and 15-HETE with the participation of cyclooxygenases, lipoxygenases, and cytochrome P-450, as well as their role in asthma pathogenesis, were discussed. The PubMed database was searched for information covering the last five years using selected inclusion criteria. Information queries included the following set of keywords: "bronchial asthma, hydroxyeicosatetraenoic acids, 5-HETE, 12-HETE, 15-HETE." Literature data indicate that the role of HETEs in human physiology and pathology, including the modulation of inflammation in asthma, requires comprehensive study to selectively modulate the enzymatic pathways of arachidonic acid metabolism leading to the production of these mediators.

Causal links between immune cells and asthma: Insights from a Mendelian Randomization analysis

Objectives Recent studies suggest immunophenotypes may play a role in asthma, but their causal relationship has not been thoroughly examined. Methods We used single nucleotide polymorphism (SNP)-derived instrumental variables. Summary data from 731 immune cell profiles and asthma cases were analyzed from genome-wide association studies (GWAS) of European populations. Mendelian Randomization (MR) analyses included inverse variance weighted (IVW), weighted median, and MR–Egger methods. Pleiotropy was assessed using the MR-Egger intercept and MR pleiotropy residual sum and outlier (MR-PRESSO) tests. Reverse MR analysis explored bidirectional causation between asthma and immunophenotypes. All statistical analyses were conducted using R software. Results MR analysis identified 108 immune signatures potentially contributing to asthma. Two immunophenotypes were significantly associated with asthma risk: CD4+ secreting Treg cells in allergic asthma (ORIVW = 1.078; 95% CI: 1.036–1.122; PIVW = 0.0002) and IgD + CD38− %lymphocyte cells in non-allergic asthma (ORIVW = 1.123; 95% CI: 1.057–1.194; PIVW = 0.0002). Conclusions This study highlights the causal associations between specific immunophenotypes and asthma risk, providing new insights into asthma pathogenesis.

Cell-Specific Contribution of IL4 Receptor α Signaling Shapes the Overall Manifestation of Allergic Airway Disease.

IL-4 and IL-13 play a critical role in allergic asthma pathogenesis via their common receptor, i.e., IL4Rα. However, the cell-specific role of IL4Rα in mixed allergens (MA)-induced allergic asthma has remained unclear. Therefore, we aimed to identify the cell-specific contribution of IL4Rα signaling in the manifestation of various pathological outcomes in mice with allergic airway disease. We compared MA-induced pathological outcomes between hematopoietic progenitor cells (HPCs)- or non-HPCs-specific IL4Rα-deficient chimera, myeloid cell-specific IL4Rα-deficient (LysMcre+/+/IL4Rαfl/fl), and airway epithelial cell-specific IL4Rα-deficient (CCSP-Cre+ /IL4Rαfl/fl) mice. Chimeric mice with systemic IL4Rα sufficiency displayed hallmark features of allergic asthma, including eosinophilic and lymphocytic infiltration, type 2 (Th2) cytokine/chemokine production, IgE production, and lung pathology. These features were markedly reduced in chimeric mice with systemic IL4Rα deficiency. Non-HPCs-specific IL4Rα-deficient mice displayed typical inflammatory features of allergic asthma but with markedly reduced mucous cell metaplasia (MCM). Deletion of IL4Rα signaling on airway epithelial cells, a subpopulation within the non-HPC lineage, resulted in almost complete absence of MCM. In contrast, all features of allergic asthma except for MCM and mucin production were mitigated in HPCs-specific IL4Rα-deficient chimeric mice. Deleting IL4Rα signaling in myeloid cells, a subpopulation within the HPC lineage, significantly alleviated MA-induced allergic airway inflammatory responses, but similar to the HPCs-specific IL4Rα-deficient chimeric mice, these mice showed significant MCM and mucin production. Our findings demonstrate that the differential allergen responsiveness seen in mice with HPCs-specific and non-HPCs-specific IL4Rα deficiency is predominantly driven by the absence of IL4Rα in myeloid cells and airway epithelial cells, respectively. Our findings also highlight distinct and mutually exclusive roles of IL4Rα signaling in mediating pathological outcomes within the myeloid and airway epithelial cell compartments.

Roles of Exosomal miRNAs in Asthma: Mechanisms and Applications.

Asthma is a chronic inflammatory disorder of the airways, characterized by a complex interplay of genetic, environmental, and immunological factors that contribute to its onset and progression. Recent advances in researches have illuminated the critical role of exosomal microRNAs (miRNAs) in the pathogenesis and development of asthma. Exosomes are nano-sized extracellular vesicles that facilitate intercellular communication by transporting a variety of bioactive molecules, including miRNAs, and play a crucial role in regulating gene expression and immune responses, which are central to the inflammatory processes underlying asthma. Exosomal miRNAs are emerging as key players in asthma due to their involvement in various aspects of the disease, including the regulation of inflammation, airway hyperresponsiveness, and remodeling. Their ability to influence the behavior of target cells and tissues makes them valuable both as diagnostic biomarkers and as potential therapeutic targets. This review aims to provide a comprehensive overview of the biogenesis of exosomes, the functional roles of exosomal miRNAs in asthma, and their clinical potential. It will explore the mechanisms by which these miRNAs contribute to asthma pathophysiology, discuss their utility in diagnosing and monitoring the disease, and highlight ongoing research efforts to harness their therapeutic potential.