Sputum microRNA-screening reveals Prostaglandin EP3 receptor as selective target in allergen-specific immunotherapy

Daphnetin alleviates allergic airway inflammation by inhibiting T-cell activation and subsequent JAK/STAT6 signaling

Allergic asthma is a major health burden on society as a chronic respiratory disease characterized by inflammation and muscle tightening around the airways in response to inhaled allergens. Daphne kiusiana Miquel is a medicinal plant that can suppress allergic airway inflammation; however, its specific molecular mechanisms of action are unclear. In this study, we aimed to elucidate the mechanisms by which D. kiusiana inhibits allergic airway inflammation. We evaluated the anti-inflammatory effects of the ethyl acetate (EA) fraction of D. kiusiana and its major compound, daphnetin, on murine T lymphocyte EL4 cells stimulated with phorbol 12-myristate 13-acetate and ionomycin in vitro and on asthmatic mice stimulated with ovalbumin in vivo. The EA fraction and daphnetin inhibited T-helper type 2 (Th2) cytokine secretion, serum immunoglobulin E production, mucus secretion, and inflammatory cell recruitment in vivo. In vitro, daphnetin suppressed intracellular Ca2+ mobilization (a critical regulator of nuclear factor of activated T cells) and functions of the activator protein 1 transcription factor to reduce interleukin (IL)-4 and IL-13 expression. Daphnetin effectively suppressed the IL-4/-13-induced activation of Janus kinase (JAK)/signal transducer and activator of transcription 6 (STAT6) signaling in vitro and in vivo, thereby inhibiting the expression of GATA3 and PDEF, two STAT6-target genes responsible for producing Th2 cytokines and mucins. These findings indicate that daphnetin suppresses allergic airway inflammation by stabilizing intracellular Ca2+ levels and subsequently inactivating the JAK/STAT6/GATA3/PDEF pathway, suggesting that daphnetin is a promising alternative to existing asthma treatments.

Celastrol alleviates airway hyperresponsiveness and inflammation in obese asthma through mediation of alveolar macrophage polarization

Obese asthma is a unique asthma phenotype that decreases sensitivity to inhaled corticosteroids, and currently lacks efficient therapeutic medication. Celastrol, a powerful bioactive substance obtained naturally from the roots of Tripterygium wilfordii, has been reported to possess the potential effect of weight loss in obese individuals. However, its role in the treatment of obese asthma is not fully elucidated. In the present study, diet-induced obesity (DIO) mice were used with or without ovalbumin (OVA) sensitization, the therapeutic effects of celastrol on airway hyperresponsiveness (AHR) and airway inflammation were examined. We found celastrol significantly decreased methacholine-induced AHR in obese asthma, as well as reducing the infiltration of inflammatory cells and goblet cell hyperplasia in the airways. This effect was likely due to the inhibition of M1-type alveolar macrophages (AMs) polarization and the promotion of M2-type macrophage polarization. In vitro, celastrol yielded equivalent outcomes in Lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells, featuring a reduction in the expression of M1 macrophage makers (iNOS, IL-1β, TNF-α) and heightened M2 macrophage makers (Arg-1, IL-10). Mechanistically, the PI3K/AKT signaling pathway has been implicated in these processes. In conclusion, we demonstrated that celastrol assisted in mitigating various parameters of obese asthma by regulating the balance of M1/M2 AMs polarization.

AllergoOncology: Biomarkers and refined classification for research in the allergy and glioma nexus-A joint EAACI-EANO position paper

Epidemiological studies have explored the relationship between allergic diseases and cancer risk or prognosis in AllergoOncology. Some studies suggest an inverse association, but uncertainties remain, including in IgE-mediated diseases and glioma. Allergic disease stems from a Th2-biased immune response to allergens in predisposed atopic individuals. Allergic disorders vary in phenotype, genotype and endotype, affecting their pathophysiology. Beyond clinical manifestation and commonly used clinical markers, there is ongoing research to identify novel biomarkers for allergy diagnosis, monitoring, severity assessment and treatment. Gliomas, the most common and diverse brain tumours, have in parallel undergone changes in classification over time, with specific molecular biomarkers defining glioma subtypes. Gliomas exhibit a complex tumour-immune interphase and distinct immune microenvironment features. Immunotherapy and targeted therapy hold promise for primary brain tumour treatment, but require more specific and effective approaches. Animal studies indicate allergic airway inflammation may delay glioma progression. This collaborative European Academy of Allergy and Clinical Immunology (EAACI) and European Association of Neuro-Oncology (EANO) Position Paper summarizes recent advances and emerging biomarkers for refined allergy and adult-type diffuse glioma classification to inform future epidemiological and clinical studies. Future research is needed to enhance our understanding of immune-glioma interactions to ultimately improve patient prognosis and survival.

Role of sulfatide-reactive vNKT cells in promoting lung Treg cells via dendritic cell modulation in asthma models

Our previous studies have showed that sulfatide-reactive type II NKT (i.e. variant NKT, vNKT) cells inhibit the immunogenic maturation during the development of mature lung dendritic cells (LDCs), leading todeclined allergic airway inflammation in asthma. Nonetheless, the specific immunoregulatory roles of vNKT cells in LDC-mediated Th2 cell responses remain incompletely understood. Herein, we found that administration of sulfatide facilitated the generation of CD4+FoxP3+ regulatory T (Treg) cells in the lungs of wild-type mice, but not in CD1d-/- and Jα18-/- mice, after ovalbumin or house dust mite exposure. This finding implies that the enhancement of lung Treg cells by sulfatide requires vNKT cells, which dependent on invariant NKT (iNKT) cells. Furthermore, the CD4+FoxP3+ Treg cells induced by sulfatide-reactive vNKT cells were found to be associated with PD-L1 molecules expressed on LDCs, and this association was dependent on iNKT cells. Collectively, our findings suggest that in asthma-mimicking murine models, sulfatide-reactive vNKT cells facilitate the generation of lung Treg cells through inducing tolerogenic properties in LDCs, and this process is dependent on the presence of lung iNKT cells. These results may provide a potential therapeutic approach to treat allergic asthma.

Integrated Omics Analysis Uncovers the Culprit behind Exacerbated Atopic Dermatitis in a Diet-Induced Obesity Model

Atopic dermatitis (AD), a chronic inflammatory skin disease, is exacerbated by obesity, yet the precise linking mechanism remains elusive. This study aimed to elucidate how obesity amplifies AD symptoms. We studied skin samples from three mouse groups: sham control, AD, and high-fat (HF) + AD. The HF + AD mice exhibited more severe AD symptoms than the AD or sham control mice. Skin lipidome analysis revealed noteworthy changes in arachidonic acid (AA) metabolism, including increased expression of pla2g4, a key enzyme in AA generation. Genes for phospholipid transport (Scarb1) and acyltransferase utilizing AA as the acyl donor (Agpat3) were upregulated in HF + AD skin. Associations were observed between AA-containing phospholipids and skin lipids containing AA and its metabolites. Furthermore, imbalanced phospholipid metabolism was identified in the HF + AD mice, marked by excessive activation of the AA and phosphatidic acid (PA)-mediated pathway. This imbalance featured increased expression of Plcb1, Plcg1, and Dgk involved in PA generation, along with a decrease in genes converting PA into diglycerol (DG) and CDP-DG (Lpin1 and cds1). This investigation revealed imbalanced phospholipid metabolism in the skin of HF + AD mice, contributing to the heightened inflammatory response observed in HF + AD, shedding light on potential mechanisms linking obesity to the exacerbation of AD symptoms.

Allergen immunotherapy combined with Notch pathway inhibitors improves HDM-induced allergic airway inflammation and inhibits ILC2 activation

Introduction

Group 2 innate lymphoid cells (ILC2s) play a crucial role in house dust mite (HDM)-induced allergic inflammation, and allergen immunotherapy (AIT) holds promise for treating the disease by reducing the frequency of ILC2s. Despite significant progress in AIT for allergic diseases, there remains a need to improve the control of allergic symptoms.

Methods

We investigated the synergistic effect of the Notch signaling pathway and subcutaneous immunotherapy (SCIT) in treating allergic airway inflammation in mice and their impact on the ratio of ILC2s in lung tissues. This was achieved by establishing the HDM-induced airway allergic disorders (HAAD) model and SCIT model. Additionally, we conducted in vitro investigations into the effect of the Notch signaling pathway on the secretory function of activated ILC2s using fluorescence-activated cell sorting. Furthermore, we explored the coactivation of the Notch signaling pathway with SCIT in vitro by sorting ILC2s from the lung tissues of mice after SCIT modeling.

Results

Previously, our group demonstrated that Notch signaling pathway inhibitors can reduce allergic airway inflammation in mice. Notch signaling induces lineage plasticity of mature ILC2s. In this study, we showed that AIT alleviates allergic airway inflammation and suppresses the frequency of ILC2s induced by HDM. Interestingly, AIT combined with a γ-secretase inhibitor (GSI), an inhibitor of the Notch signaling pathway, significantly inhibited the frequency of ILC2s, reduced airway inflammation, and suppressed Th2-type responses in a mouse model. Furthermore, lung ILC2s from HDM-challenged mice with or without AIT were treated with GSI in vitro, and we found that GSI dramatically reduced the secretion of type 2 inflammatory factors in ILC2s.

Discussion

These findings suggest that Notch signaling pathway inhibitors can be used as adjuvant therapy for AIT and may hold potential treatment value in the cooperative control of allergic airway inflammation during early AIT.

Proinflammatory pattern in the lower airways of non-asthmatic obese adolescents

BACKGROUND

Obesity is known to be a pro-inflammatory condition affecting multiple organs. Obesity as a systemic pro-inflammatory state, might be associated with bronchial inflammation in non-smoking adolescents with a BMI ≥ 30 kg/m2 without evidence of concomitant chronic diseases.

MATERIALS AND METHODS

We studied non-asthmatic obese patients (n = 20; median age 15.8 years; BMI 35.0 kg/m2) compared to age matched healthy control subjects (n = 20; median age 17.5 years; BMI 21.5 kg/m2). Induced sputum differential cell counts and sputum mRNA levels were assessed for all study subjects. Serum levels of CRP, IL-6, and IL-8 were measured. Further, IL-5, IL-6, IL-8, IL-13, IL-17, TNF-α, IFN-γ, and IP-10 protein levels were analyzed in induced sputum was.

RESULTS

Serum CRP levels, sputum inflammatory cell load and sputum eosinophils differed significantly between obese and non-obese subjects, for sputum neutrophils, a correlation was shown with BMI ≥ 30 kg/m2. Differences were also observed for sputum mRNA expression of IL6, IL8, IL13, IL17, IL23, and IFN-γ, as well as the transcription factors T-bet, GATA3, and FoxP3.

CONCLUSIONS

Increased bronchial inflammation, triggered by systemic or local inflammatory effects of obesity itself, may account for the higher rates of airway disease in obese adolescents.

Long noncoding RNA antisense noncoding RNA in the INK4 locus inhibition alleviates airway remodeling in asthma through the regulation of the microRNA-7-5p/early growth response factor 3 axis

Asthma, a chronic inflammatory disease of the airways, clinically manifests as airway remodeling. The purpose of this study was to probe the potential role of long noncoding RNA (lncRNA) antisense noncoding RNA in the INK4 locus (lncRNA ANRIL) in the proliferation and migration of airway smooth muscle cell (ASMC) and to explore its potential mechanisms in asthma. Serum samples were obtained from 30 healthy volunteers and 30 patients with asthma. Additionally, platelet-derived growth factor-BB (PDGF-BB) was used to induce airway remodeling in ASMCs. The level of lncRNA ANRIL and microRNA (miR)-7-5p in serum samples were measured by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). TargetScan predicted the binding site of miR-7-5p to early growth response factor 3 (EGR3) and validated the results using a dual-luciferase reporter assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and Transwell assays were used to detect cellular proliferation and migration, respectively. Subsequently, changes in proliferation- and migration-related genes were verified using western blot analysis and qRT-PCR. These results indicate that lncRNA ANRIL was upregulated in the serum and PDGF-BB-induced ASMCs of patients with asthma, whereas miR-7-5p expression was reduced. EGR3 was a direct target of miR-7-5p. LncRNA ANRIL silencing inhibited the proliferation or migration of ASMCs induced by PDGF-BB through miR-7-5p upregulation. Mechanistic studies indicated that miR-7-5p inhibits the proliferation or migration of PDGF-BB-induced ASMCs by decreasing EGR3 expression. EGR3 upregulation reverses the role of miR-7-5p in airway remodeling. Thus, downregulation of lncRNA ANRIL inhibits airway remodeling through inhibiting the proliferation and migration of PDGF-BB-induced ASMCs by regulating miR-7-5p/EGR3 signaling.

Non-Coding RNAs in Pulmonary Diseases: Comparison of Different Airway-Derived Biosamples

Due to their structural conservation and functional role in critical signalling pathways, non-coding RNA (ncRNA) is a promising biomarker and modulator of pathological conditions. Most research has focussed on the role of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules have been investigated both in a cellular and an extracellular context. Sources of ncRNAs may include organ-specific body fluids. Therefore, studies on ncRNAs in respiratory diseases include those on sputum, bronchoalveolar lavage fluid (BALF) and exhaled breath condensate (EBC). It is worth identifying the limitations of these biosamples in terms of ncRNA abundance, processing and diagnostic potential. This review describes the progress in the literature on the role of ncRNAs in the pathogenesis and progression of severe respiratory diseases, including cystic fibrosis, asthma and interstitial lung disease. We showed that there is a deficit of information on lncRNAs and circRNAs in selected diseases, despite attempts to functionally bind them to miRNAs. miRNAs remain the most well-studied, but only a few investigations have been conducted on the least invasive biosample material, i.e., EBC. To summarise the studies conducted to date, we also performed a preliminary in silico analysis of the reported miRNAs, demonstrating the complexity of their role and interactions in selected respiratory diseases.

Application of Extracellular Vesicles in Allergic Rhinitis: A Systematic Review

The pathophysiology of allergic rhinitis (AR), one of the most common diseases in the world, is still not sufficiently understood. Extracellular vesicles (EVs), which are secreted by host and bacteria cells and take part in near and distant intracellular communication, can provide information about AR. Recently, attention has been drawn to the potential use of EVs as biomarkers, vaccines, or transporters for drug delivery. In this review, we present an up-to-date literature overview on EVs in AR to reveal their potential clinical significance in this condition. A comprehensive and systematic literature search was conducted following PRISMA statement guidelines for original, completed articles, available in English concerning EVs and AR. For this purpose, PubMed/MEDLINE, Scopus, Web of Science, and Cochrane, were searched up until 10 Novenmber 2022. From 275 records, 18 articles were included for analysis. The risk of bias was assessed for all studies as low or moderate risk of overall bias using the Office and Health Assessment and Translation Risk of Bias Rating Tool for Human and Animal Studies. We presented the role of exosomes in the pathophysiology of AR and highlighted the possibility of using exosomes as biomarkers and treatment in this disease.

Extracellular Vesicles Derived from Allergen Immunotherapy-Treated Mice Suppressed IL-5 Production from Group 2 Innate Lymphoid Cells

Allergen immunotherapy (AIT), such as subcutaneous immunotherapy (SCIT), is a treatment targeting the causes of allergic diseases. The roles of extracellular vesicles (EVs), bilayer lipid membrane blebs released from all types of cells, in AIT have not been clarified. To examine the roles of EVs in SCIT, it was analyzed whether (1) EVs are phenotypically changed by treatment with SCIT, and (2) EVs derived from SCIT treatment suppress the function of group 2 innate lymphoid cells (ILC2s), which are major cells contributing to type 2 allergic inflammation. As a result, (1) expression of CD9, a canonical EV marker, was highly up-regulated by SCIT in a murine model of asthma; and (2) IL-5 production from ILC2s in vitro was significantly decreased by the addition of serum EVs derived from SCIT-treated but not non-SCIT-treated mice. In conclusion, it was indicated that EVs were transformed by SCIT, changing to a suppressive phenotype of type 2 allergic inflammation.

TAFA4-IL-10 axis potentiate immunotherapy for airway allergy by induction of specific regulatory T cells

Allergen-specific immunotherapy (AIT) is the main treatment for allergic diseases. The therapeutic efficacy of AIT has to be improved. Neuropeptides, such as TAFA4, have immune-regulating features. The objective of this study is to promote the efficacy of AIT in experimental allergic rhinitis (AR) by the concurrent use of TAFA chemokine as a family member 4 (TAFA4). In this study, an AR mouse model was developed using ovalbumin (OVA) as the specific antigen. The AR response was assessed in mice after treatment with AIT or/and TAFA4. We found that exposure to TAFA4 activated dendritic cells (DCs) in the airway tissues. Activation of DC by TAFA4 resulted in the expression of IL-10. TAFA4 also promoted the activities of c-Maf inducing protein. The FPR1-MyD88-AKT signal pathway was associated with the TAFA4-induced Il10 expression in the DCs. Co-administration of AIT/TAFA4 attenuated the AR response in mice by inducing antigen-specific Tr1 cells. In conclusion, TAFA4 induces the expression of IL-10 in DCs. Acting as an adjuvant, TAFA4 significantly improves AIT’s therapeutic efficacy against AR by inducing antigen-specific Tr1 cells.

Role of microRNAs in type 2 diseases and allergen-specific immunotherapy

MicroRNAs (miRs) have gained scientific attention due to their importance in the pathophysiology of allergic diseases as well as their potential as biomarkers in allergen-specific treatment options. Their function as post-transcriptional regulators, controlling various cellular processes, is of high importance since any single miR can target multiple mRNAs, often within the same signalling pathway. MiRs can alter dysregulated expression of certain cellular responses and contribute to or cause, but in some cases prevent or repress, the development of various diseases. In this review article, we describe current research on the role of specific miRs in regulating immune responses in epithelial cells and specialized immune cells in response to various stimuli, in allergic diseases, and regulation in the therapeutic approach of allergen-specific immunotherapy (AIT). Despite the fact that AIT has been used successfully as a causative treatment option since more than a century, very little is known about the mechanisms of regulation and its connections with microRNAs. In order to fill this gap, this review aims to provide an overview of the current knowledge.

Roles of type 1 regulatory T (Tr1) cells in allergen-specific immunotherapy

Allergen-specific immunotherapy (AIT) is the only causative treatment for allergic diseases by modification of the immune response to allergens. A key feature of AIT is to induce immunotolerance to allergens by generating antigen-specific regulatory T (Treg) cells in allergic patients. Type 1 regulatory T (Tr1) cells and forkhead box protein 3 (Foxp3)-expressing Treg cells are well known among Treg cell subsets. Foxp3 was identified as a master transcription factor of Treg cells, and its expression is necessary for their suppressive activity. In contrast to Foxp3⁺ Treg cells, the master transcription factor of Tr1 cells has not been elucidated. Nevertheless, Tr1 cells are generally considered as a distinct subset of Treg cells induced in the periphery during antigen exposure in tolerogenic conditions and can produce large amounts of anti-inflammatory cytokines such as interleukin-10 and transforming growth factor-β, followed by down-regulation of the function of effector immune cells independently of Foxp3 expression. Since the discovery of Tr1 cells more than 20 years ago, research on Tr1 cells has expanded our understanding of the mechanism of AIT. Although the direct precursors and true identity of these cells continues to be disputed, we and others have demonstrated that Tr1 cells are induced in the periphery by AIT, and the induced cells are re-activated by antigens, followed by suppression of allergic symptoms. In this review, we discuss the immune mechanisms for the induction of Tr1 cells by AIT and the immune-suppressive roles of Tr1 cells in AIT.

The Novel Regulatory Role of the lncRNA–miRNA–mRNA Axis in Chronic Inflammatory Airway Diseases

Chronic inflammatory airway diseases, characterized by airway inflammation and airway remodelling, are increasing as a cause of morbidity and mortality for all age groups and races across the world. The underlying molecular mechanisms involved in chronic inflammatory airway diseases have not been fully explored. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) have recently attracted much attention for their roles in the regulation of a variety of biological processes. A number of studies have confirmed that both lncRNAs and miRNAs can regulate the initiation and progression of chronic airway diseases by targeting mRNAs and regulating different cellular processes, such as proliferation, apoptosis, inflammation, migration, and epithelial–mesenchymal transition (EMT). Recently, accumulative evidence has shown that the novel regulatory mechanism underlying the interaction among lncRNAs, miRNAs and messenger RNAs (mRNAs) plays a critical role in the pathophysiological processes of chronic inflammatory airway diseases. In this review, we comprehensively summarized the regulatory roles of the lncRNA–miRNA–mRNA network in different cell types and their potential roles as biomarkers, indicators of comorbidities or therapeutic targets for chronic inflammatory airway diseases, particularly chronic obstructive pulmonary disease (COPD) and asthma.

Bronchial inflammation biomarker patterns link humoral immunodeficiency with bronchiectasis-related small airway dysfunction

BACKGROUND

The progression of chronic destructive lung disease in patients with humoral immunodeficiency (ID) and concomitant development of bronchiectasis is difficult to prevent. Lung function tests in these patients typically show bronchial obstruction of the small airways in combination with increased air trapping in the distal airways, which is consistent with small airway dysfunction.

OBJECTIVE

The objective was to assess the grade of chronic lower airway inflammation and small airway dysfunction from induced sputum and the corresponding local pro-inflammatory mediator pattern to discriminate patients affected by bronchiectasis-related Small Airway Dysfunction (SAD).

METHODS

In a prospective design, 22 patients with ID (14 CVID, 3 XLA, 3 hyper-IgM syndrome, 1 hyper-IgE syndrome and low IgG levels due to treatment with rituximab and 1 SCID after BMT and persistent humoral defect) and 21 healthy controls were examined. Lung function, Fraction Expiratory Nitric Oxide (FeNO) and pro-inflammatory cytokine levels were compared in subsets of patients with (ID + BE) and without bronchiectasis (ID) pre-stratified using high-resolution computed tomography (HRCT) scans and control subjects.

RESULTS

Analysis of induced sputum showed significantly increased total cell counts and severe neutrophilic inflammation in ID. The concomitant SAD revealed higher total cell numbers compared to ID. Bronchial inflammation in ID is clearly mirrored by pro-inflammatory mediators IL-1β, IL-6 and CXCL-8, whilst TNF-α revealed a correlation with lung function parameters altered in the context of bronchiectasis-related Small Airway Dysfunction.

CONCLUSIONS

In spite of immunoglobulin substitution, bronchial inflammation was dominated by neutrophils and was highly increased in patients with ID + BE. Notably, the pro-inflammatory cytokines in patients with ID were significantly increased in induced sputum. The context-dependent cytokine pattern in relation to the presence of concomitant bronchiectasis associated with SAD in ID patients could be helpful in delimiting ID patient subgroups and individualizing therapeutic approaches.

Role of Respiratory Epithelial Cells in Allergic Diseases

The airway epithelium provides the first line of defense to the surrounding environment. However, dysfunctions of this physical barrier are frequently observed in allergic diseases, which are tightly connected with pro- or anti-inflammatory processes. When the epithelial cells are confronted with allergens or pathogens, specific response mechanisms are set in motion, which in homeostasis, lead to the elimination of the invaders and leave permanent traces on the respiratory epithelium. However, allergens can also cause damage in the sensitized organism, which can be ascribed to the excessive immune reactions. The tight interaction of epithelial cells of the upper and lower airways with local and systemic immune cells can leave an imprint that may mirror the pathophysiology. The interaction with effector T cells, along with the macrophages, play an important role in this response, as reflected in the gene expression profiles (transcriptomes) of the epithelial cells, as well as in the secretory pattern (secretomes). Further, the storage of information from past exposures as memories within discrete cell types may allow a tissue to inform and fundamentally alter its future responses. Recently, several lines of evidence have highlighted the contributions from myeloid cells, lymphoid cells, stromal cells, mast cells, and epithelial cells to the emerging concepts of inflammatory memory and trained immunity.

Chronic Allergen Challenge Induces Corticosteroid Insensitivity With Persistent Airway Remodeling and Type 2 Inflammation

Type 2-high severe asthma is described as a distinct endotype with Th2 inflammation, high eosinophil lung infiltration, impaired lung function, and reduced corticosteroid sensitivity. While the inflammatory milieu is similar to mild asthma, patients with type 2-high severe asthma likely have underlying mechanisms that sustain asthma pathophysiology despite corticosteroid treatments. Acute and chronic allergen models induce robust type 2 inflammatory responses, however differences in corticosteroid sensitivity remains poorly understood. In the present study, we sensitized and challenged mice with ovalbumin (OVA; acute model) or mixed allergens (MA; chronic model). Corticosteroid sensitivity was assessed by administering vehicle, 1, or 3 mg/kg fluticasone propionate (FP) and examining key asthmatic features such as airway inflammation, remodeling, hyperresponsiveness, and antioxidant capacity. Both acute and chronic allergen exposure exhibited enhanced AHR, immune cell infiltration, airway inflammation, and remodeling, but corticosteroids were unable to fully alleviate inflammation, AHR, and airway smooth muscle mass in MA-challenged mice. While there were no differences in antioxidant capacity, persistent IL-4+ Th2 cell population suggests the MA model induces type 2 inflammation that is insensitive to corticosteroids. Our data indicate that chronic allergen exposure is associated with more persistent type 2 immune responses and corticosteroid insensitivity. Understanding differences between acute and chronic allergen models could unlock underlying mechanisms related to type 2-high severe asthma.