Pulmonary expression of interleukin-13 causes inflammation, mucus hypersecretion, subepithelial fibrosis, physiologic abnormalities, and eotaxin production

Strain and sex differences in chloromethylisothiazolinone and methylisothiazolinone-induced lung injury in mice

Mouse strain and sex variability may provide a better understanding of the isothiazolinone-associated respiratory toxicity profile; however, this remains poorly understood. In this study, we investigated and compared the respiratory effects of repeated exposure to a mixture of chloromethylisothiazolinone and methylisothiazolinone (CMIT/MIT) in two commonly used mouse strains, BALB/c and C57BL/6, including both males and females. CMIT/MIT-induced lung injury was analyzed after six times intratracheal instillation of CMIT/MIT using differential cell counts and cytokine measurements in bronchoalveolar lavage fluid (BALF), histological analysis, and gene expression profiling of lung tissue. In both female and male C57BL/6 mice, CMIT/MIT exposure led to increased infiltration of inflammatory cells, particularly eosinophils, and elevated levels of Type 2 helper T cell (Th2)-associated cytokines in BALF. Histopathological findings revealed granulomatous inflammation, mucinous cell hyperplasia, eosinophilic cell infiltration, and lung fibrosis in these mice. Female BALB/c mice exhibited similar but less severe pathological changes. In contrast, male BALB/c mice showed a predominance of macrophages and neutrophils, with no notable histopathological alterations. Gene expression analysis revealed upregulation of genes associated with inflammatory and fibrotic lung injury and Th2 signaling in female and male C57BL/6 mice and female BALB/c mice, but not in male BALB/c mice. Collectively, these findings indicate that C57BL/6 mice are more susceptible to CMIT/MIT-induced lung injury than BALB/c mice, which is closely associated with the genetic characteristics of increased eosinophil and Th2-mediated responses.

Systemic EP4 receptor agonist and Arginase-1 therapy in a murine model of chronic asthma and influenza virus-induced asthma exacerbation

BACKGROUND AND PURPOSE

Myeloid-derived suppressor cells (MDSCs) play important roles in the pathogenesis of asthma. Recent studies demonstrate that their function can be modulated by different pharmacological approaches. In this study, we focussed on the effects of systemically administered prostaglandin EP4 receptor agonist L-902,688 and pegylated human Arginase-1 on MDSCs in a murine model of chronic asthma and asthma exacerbation.

EXPERIMENTAL APPROACH

BALB/c mice were challenged with house dust mite (HDM) over a period of 5 weeks, establishing a chronic asthma phenotype. To induce asthma exacerbation, mice were infected with Influenza Virus H1N1 A/Puerto Rico/8/1934. In vivo lung function, lung inflammatory features, number and suppressive activity of MDSCs, number of different T cell subsets in lung and spleen and viral titer in the bronchoalveolar lavage fluid (BALF) were assessed.

KEY RESULTS

In asthmatic mice, treatment with the EP4 receptor agonist or Arginase-1 significantly reduced the number of eosinophils in the BALF. Both treatments improved lung function and ameliorated airway hyperresponsiveness (AHR) in asthma exacerbation. The number and suppressive activity of MDSCs in the lung were increased by virus-induced asthma exacerbation.

CONCLUSION AND IMPLICATIONS

We found beneficial effects of systemic EP4 receptor agonist and Arginase-1 therapy in a murine model of chronic asthma and influenza virus-induced asthma exacerbation. Our findings highlight the potential efficacy of EP4 receptor agonists, Arginase-1, and MDSCs, as novel therapeutic approaches in asthma and asthma exacerbation.

Quantitative adverse outcome pathway modeling for cigarette-smoke-induced airway mucus hypersecretion. Part 1: adverse-outcome-pathway-based in vitro assessment with repeated exposure to whole cigarette smoke

Adverse outcome pathway (AOP)-based chemical risk assessment is a promising tool for regulatory decision-making and is typically used in toxicological assessments. However, it also holds potential for pharmacological and disease-related evaluations. The present study focuses on an AOP for decreased lung function. Lung function is normally robustly maintained by homeostatic capacity, but repeated and chronic stimulation can disrupt this capacity, leading to impaired lung function and mucus hypersecretion. We developed an AOP-based in vitro method to test the disease-related states that can be reproduced by exposing three-dimensionally cultured human bronchial epithelial cells (3D-HBECs) to whole cigarette smoke (WCS). Over a duration of 2 weeks, we repeatedly exposed 3D-HBECs from six different donors to WCS six times to observe both acute phase responses (oxidative stress, epidermal growth factor receptor activation, and SP1 activation) and chronic phase responses (intracellular mucus production, goblet cell metaplasia/hyperplasia, and mucus hypersecretion) along the AOP. Our results demonstrate that although the repeated exposure to WCS induced biological responses along the AOP in all donors, there were interdonor differences, particularly in the timing and amplitudes of the chronic phase responses. All smokers do not exhibit phenotypic changes with the same smoking duration, so this variability likely reflects individual differences. We anticipate that our AOP-based assessment method combined with computational quantitative AOP modeling (discussed in Part 2) will become a valuable tool for assessing the disease risk of airborne materials and inhalable products.

Dupilumab reduces acute exacerbations and improves lung function in patients with COPD with type 2 inflammation irrespective of body mass index, airflow obstruction, dyspnea, and exercise capacity index scores

BACKGROUND

The body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index predicts 5-year mortality risk in chronic obstructive pulmonary disease (COPD); higher scores predict worse outcomes. Dupilumab, a fully human monoclonal antibody that blocks the shared receptor component for interleukin-4/13, reduced exacerbations and improved lung function in patients with COPD in the phase 3 BOREAS trial (NCT03930732). We assessed dupilumab efficacy in patients with COPD and type 2 inflammation by baseline BODE index.

METHODS

Patients with COPD, moderate-to-severe airflow limitation, screening blood eosinophils ≥300 cells/μL, and high exacerbation risk, on triple therapy, received 300 mg add-on dupilumab or placebo every 2 weeks for 52 weeks. Annualized moderate or severe COPD exacerbation rate and change from baseline in pre-bronchodilator forced expiratory volume in 1 s (FEV1) at Weeks 12 and 52 were assessed by baseline BODE index, categorized as low (≤4) or high (>4).

RESULTS

Of 934 patients with reported baseline BODE index scores (dupilumab: 470; placebo: 464), 61.8 % had scores ≤4. Dupilumab reduced exacerbations versus placebo, regardless of baseline BODE index group. Exacerbation reductions were similar by BODE index group; relative risk (95 % confidence interval) for patients with BODE index >4 versus ≤4 was 0.656 (0.496-0.868) versus 0.718 (0.547-0.944). At Weeks 12 and 52, dupilumab consistently improved pre-bronchodilator FEV1 versus placebo, regardless of baseline BODE index group.

CONCLUSION

Dupilumab reduced exacerbations and improved lung function in patients with COPD and type 2 inflammation irrespective of baseline BODE index score.

CLINICAL TRIAL REGISTRATION NUMBER

BOREAS trial NCT03930732.

Molecular Hydrogen Ameliorates Anti-Desmoglein 1 Antibody-Induced Pemphigus-Associated Interstitial Lung Disease by Inhibiting Oxidative Stress

Pemphigus-associated interstitial lung disease (P-ILD) is a severe complication observed in pemphigus patients that is characterized by pulmonary interstitial inflammation and fibrosis. This study investigated the role of anti-desmoglein (Dsg) 1/3 antibodies in P-ILD pathogenesis and evaluated the therapeutic potential of molecular hydrogen (H2). Using a BALB/cJGpt mouse model, we demonstrated that anti-Dsg 1 antibodies, but not anti-Dsg 3 antibodies, induced interstitial inflammation and fibrosis. Immunofluorescence staining confirmed IgG deposition in the alveolar epithelium, suggesting immune complex formation and epithelial damage. Gene expression analysis revealed elevated pro-inflammatory cytokines (IL-1β, IL-13) and upregulated pro-fibrotic markers (α-SMA, S100A4, TGF-β, and collagen genes) in P-ILD progression. Elevated oxidative stress and impaired ROS metabolism further implied the role of oxidative damage in disease pathogenesis. To assess H2's therapeutic potential, hydrogen-rich water was administered to P-ILD mice. H2 treatment significantly reduced oxidative stress, attenuated interstitial inflammation, and prevented pulmonary fibrosis. These protective effects were attributed to H2's antioxidant properties, which restored the pro-oxidant-antioxidant balance. Our findings underscore the critical role of anti-Dsg 1 antibodies and oxidative stress in P-ILD and highlight H2 as a promising therapeutic agent for mitigating anti-Dsg 1 antibody-induced lung injury.

Targeting IL-13 and IL-4 in Asthma: Therapeutic Implications on Airway Remodeling in Severe Asthma

Asthma is a chronic respiratory disorder affecting individuals across all age groups. It is characterized by airway inflammation and remodeling and leads to progressive airflow restriction. While corticosteroids remain a mainstay therapy, their efficacy is limited in severe asthma due to genetic and epigenetic alterations, as well as elevated pro-inflammatory cytokines interleukin-4 (IL-4), interleukin-13 (IL-13), and interleukin-5 (IL-5), which drive structural airway changes including subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia. This underscores the critical need for biologically targeted therapies. This review systematically examines the roles of IL-4 and IL-13, key drivers of type-2 inflammation, in airway remodeling and their potential as therapeutic targets. IL-4 orchestrates eosinophil recruitment, immunoglobulin class switching, and Th2 differentiation, whereas IL-13 directly modulates structural cells, including fibroblasts and epithelial cells, to promote mucus hypersecretion and extracellular matrix (ECM) deposition. Despite shared signaling pathways, IL-13 emerges as the dominant cytokine in remodeling processes including mucus hypersecretion, fibrosis and smooth muscle hypertrophy. While IL-4 primarily amplifies inflammatory cascades by driving IgE switching, promoting Th2 cell polarization that sustain cytokine release, and inducing chemokines to recruit eosinophils. In steroid-resistant severe asthma, biologics targeting IL-4/IL-13 show promise in reducing exacerbations and eosinophilic inflammation. However, their capacity to reverse established remodeling remains inconsistent, as clinical trials prioritize inflammatory biomarkers over long-term structural outcomes. This synthesis highlights critical gaps in understanding the durability of IL-4/IL-13 inhibition on airway structure and advocates for therapies combining biologics with remodeling-specific strategies. Through the integration of mechanistic insights and clinical evidence, this review emphasizes the need for long-term studies utilizing advanced imaging, histopathological techniques, and patient-reported outcomes to evaluate how IL-4/IL-13-targeted therapies alter airway remodeling and symptom burden, thereby informing more effective treatment approaches for severe, steroid-resistant asthma.

Exogenous acetate mitigates later enhanced allergic airway inflammation in a menopausal mouse model

Introduction

Asthma, an inflammatory lung disease, disproportionately affects women in adulthood and is associated with a decline in estrogen levels during the menstrual cycle and menopause. To study asthma symptoms during menopause, we used a mouse model of postmenopausal asthma via ovariectomy (OVx). Similar to human menopause, we previously discovered that re-exposure of allergic OVx mice to allergen exacerbates lung inflammation. Surprisingly, we found that probiotic treatment alleviates this inflammatory exacerbation and produces acetate as one of its metabolites. Here, we investigate whether exogenous acetate alone can inhibit the exacerbation of experimental asthma in menopause.

Methods

Mice received acetate administration before and during sensitization. After challenge and OVx the mice were subjected to a second challenge to test whether acetate protected against airway inflammation after menopause induction.

Results

Acetate administration reduced all lung T2 inflammatory responses, as well as the serum immunoglobulin (IgE) level. Early acetate treatment led to an increase in regulatory T cells, even 3 weeks after cessation of the treatment, suggesting that the increase in Treg percentage is associated with the reduction of type 2 inflammation in the airways after menopause induction, indicating its potential role in this process. Given the significant role of the lung-gut axis in asthma and the association of asthma and menopause with intestinal dysfunctions, this finding is particularly relevant; we also analyzed several markers of intestinal integrity. Compared with sham-operated mice, rechallenged allergic menopausal mice had a reduction in the intestinal epithelial genes, MUC2 and OCLN, and preventive supplementation with acetate returned their expression to normal. No change was found in menopausal mice without allergic inflammation.

Conclusion

In conclusion, treatment with acetate prior to estrogen level decline protects sensitized and challenged mice against later airway T2 inflammation and may restore gut homeostasis.

Adoptive Transfer of T Cells as a Potential Therapeutic Approach in the Bleomycin-Injured Mouse Lung

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a lethal disease with an unknown etiology and complex pathophysiology that are not fully understood. The disease involves intricate cellular interplay, particularly among various immune cells. Currently, there is no treatment capable of reversing the fibrotic process or aiding lung regeneration. Hepatocyte growth factor (HGF) has demonstrated antifibrotic properties, whereas the adoptive transfer of modified T cells is a well-established treatment for various malignancies. We aimed to understand the dynamics of T cells in the progression of lung fibrosis and to study the therapeutic benefit of adoptive T cell transfer in a bleomycin-injured mouse lung (BLM) model.

METHODS

T cells were isolated from the spleen of naïve mice and transfected in vitro with mouse HGF plasmid and were administered intratracheally to the mice lungs 7 days post-bleomycin injury to the lung. Lung tissue and bronchoalveolar lavage were collected and analyzed using flow cytometry, histology, qRT-PCR, ELISA, and hydroxyproline assay.

RESULTS

Our findings demonstrate the successful T cell therapy of bleomycin-induced lung injury through the adoptive transfer of HGF-transfected T cells in mice. This treatment resulted in decreased collagen deposition and a balancing of immune cell exhaustion and cytokine homeostasis compared with untreated controls. In vitro testing showed enhanced apoptosis in myofibroblasts induced by HGF-overexpressing T cells.

CONCLUSIONS

Taken together, our data highlight the great potential of adoptive T cell transfer as an emerging therapy to counteract lung fibrosis.

Predicting dupilumab effectiveness with Type-2 biomarkers: A real-world study of severe asthma

BACKGROUND

The therapeutic effectiveness of dupilumab for severe asthma in real-world settings is yet to be prospectively investigated across multiple institutions, and uncertainties persist regarding predictive factors for its effectiveness. We aimed to assess the effectiveness of dupilumab and identify predictors of its effectiveness in real-world settings using two type-2 biomarkers: FeNO concentration and blood eosinophil count.

METHODS

This prospective multicenter study included 103 patients with severe asthma. Exacerbations and respiratory functions were monitored for 24 weeks. Asthma control was evaluated using the Asthma Control Questionnaire-5. Clinical symptoms and their impact on cough and sputum were assessed using the Cough and Sputum Assessment Questionnaire (CASA-Q). Subgroup analyses of type-2 biomarkers were conducted based on FeNO levels and blood eosinophil counts at baseline.

RESULTS

Treatment with dupilumab led to a reduction in exacerbations and enhancement in asthma control, FEV1, and CASA-Q scores. FEV1 improvement was correlated with enhancement in the sputum domain of the CASA-Q. Patients exhibiting elevated FeNO levels and blood eosinophil counts demonstrated more significant enhancements in FEV1. CASA-Q sputum domain scores were significantly higher in the group with elevated eosinophil counts. Regression analysis revealed that FeNO levels and blood eosinophil counts are significant predictors of FEV1 improvement, with blood eosinophil counts also predicting sputum improvement in patients treated with dupilumab.

CONCLUSIONS

Type-2 biomarkers may act as indicators of improvement in FEV1 and sputum outcomes among patients with severe asthma undergoing dupilumab treatment in real-world settings.

Molecular mechanisms and clinical impact of biologic therapies in severe asthma

Severe asthma is a critical condition for patients with asthma, characterized by frequent exacerbations, decreased pulmonary function, and unstable symptoms related to asthma. Consequently, the administration of systemic corticosteroids, which cause secondary damage because of their adverse effects, is considered. Recently, several types of molecular-targeted biological therapies have become available for patients with severe asthma, and they have a capacity to improve the pathophysiology of severe asthma. However, several clinical reports indicate that the effects differ depending on the biological targets of asthma in individual patients. In this review, the molecular mechanisms and clinical impact of biologic therapies in severe asthma are described. In addition, molecules targeted by possible future biologics are also addressed. Better understanding of the mechanistic basis for the role of biologics in severe asthma could lead to new therapeutic options for these patients.

Unlocking lung regeneration: insights into progenitor cell dynamics and metabolic control

Regenerative responses are particularly important in the lungs, which are critical for gas exchange and frequently challenged by environmental insults. The lung progenitor cells play a central role in the lung regeneration response, and their dysfunction is associated with various lung diseases. Understanding the mechanisms regulating lung progenitor cell function is essential for developing new therapeutic approaches to promote lung regeneration. This review summarizes recent advancements in the field of lung regeneration, focusing on the metabolic control of lung progenitor cell function. We discuss cell lineage plasticity and cell-cell signaling under different physiological conditions. Additionally, we highlight the connection between progenitor cell dysfunction and lung diseases, emphasizing the need to develop new therapeutic strategies in regenerative medicine to improve lung regenerative capacity.

Increased Muc5AC and Decreased Ciliated Cells in Severe Asthma Partially Restored by Inhibition of IL-4Rα Receptor

Rationale: The role of IL-13 on the airway epithelium in severe asthma leading to airway remodeling remains poorly understood. Objectives: To study IL-13-induced airway remodeling on goblet cells and cilia in the airway epithelium in severe asthma and the impact of an anti-IL4Rα antibody, dupilumab, in vitro. Methods: Quantitative computed tomography of the lungs and endobronchial biopsies and brushings were obtained in 51 participants (22 with severe asthma, 11 with nonsevere asthma, and 18 healthy participants) in SARPIII (Severe Asthma Research Program III) and measured for mucin and cilia-related proteins. Epithelial cells were differentiated at air-liquid interface (ALI) with IL-13 with or without dupilumab and assessed for mucin, cilia, cilia beat frequency (CBF), and epithelial integrity (transepithelial electrical resistance [TEER]). Measurements and Main Results: Increased Muc5AC (mucin 5AC) (Δ + 263.2 ± 92.7 luminosity/epithelial area) and decreased ciliated cells (Δ - 0.07 ± 0.03 Foxj1+ cells/epithelial area) were observed in biopsies from patients with severe asthma when compared with healthy control subjects (P < 0.01 and P = 0.047, respectively). RNA sequencing of endobronchial cell brushings confirmed a Muc5AC increase with a decrease in a five-gene cilia-related mean in patients with severe asthma compared with healthy subjects (all P < 0.05). IL-13 (5 ng/ml)-differentiated ALI cultures of healthy and asthmatic samples (from participants with severe and nonsevere asthma) increased Muc5AC, decreased cilia (α-aceytl-tubulin) in samples from healthy participants (Δ + 6.5% ± 1.5%, Δ - 14.1% ± 2.7%; all P < 0.001 respectively) and participants with asthma (Δ + 4.4% ± 2.5%, Δ - 13.1% ± 2.7%; P = 0.084, P < 0.001 respectively), and decreased epithelial integrity (TEER) in samples from healthy participants (-140.9 ± 21.3 [ohms], P < 0.001), while decreasing CBF in samples from participants with asthma (Δ - 4.4 ± 1.7 [Hz], P < 0.01). When dupilumab was added to ALI with IL-13, there was no significant decrease in Mu5AC, but there was restoration of cilia in healthy participants and participants with asthma (absolute increase of 67.5% and 32.5% cilia, all P < 0.05, respectively), whereas CBF increased (Δ + 3.6 ± 1.1 [Hz], P < 0.001) and TEER decreased (only in asthma, Δ - 37.8 ± 16.2 [ohms], P < 0.05). Conclusions: IL-13 drives features of airway remodeling in severe asthma, which are partially reversed by inhibiting the IL-4Rα receptor in vitro.

Cell-Specific Contribution of IL-4 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 IL-4Rα. However, the cell-specific role of IL-4Rα in mixed allergen (MA)-induced allergic asthma has remained unclear. Therefore, we aimed to identify the cell-specific contribution of IL-4Rα signaling in the manifestation of various pathological outcomes in mice with allergic airway disease. We compared MA-induced pathological outcomes between hematopoietic progenitor cell (HPC)- or non-HPC-specific IL-4Rα-deficient chimera, myeloid cell-specific IL-4Rα-deficient (LysMcre+/+IL-4Rαfl/fl), and airway epithelial cell-specific IL-4Rα-deficient (CCSP-Cre+/IL-4Rαfl/fl) mice. Chimeric mice with systemic IL-4Rα sufficiency displayed hallmark features of allergic asthma, including eosinophilic and lymphocytic infiltration, type 2 (T-helper type 2) cytokine/chemokine production, IgE production, and lung pathology. These features were markedly reduced in chimeric mice with systemic IL-4Rα deficiency. Non-HPC-specific IL-4Rα-deficient mice displayed typical inflammatory features of allergic asthma but with markedly reduced mucous cell metaplasia (MCM). Deletion of IL-4Rα 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 HPC-specific IL-4Rα-deficient chimeric mice. Deleting IL-4Rα signaling in myeloid cells, a subpopulation within the HPC lineage, significantly alleviated MA-induced allergic airway inflammatory responses, but, similar to the HPC-specific IL-4Rα-deficient chimeric mice, these mice showed significant MCM and mucin production. Our findings demonstrate that the differential allergen responsiveness seen in mice with HPC-specific and non-HPC-specific IL-4Rα deficiency is predominantly driven by the absence of IL-4Rα in myeloid cells and airway epithelial cells, respectively. Our findings also highlight distinct and mutually exclusive roles of IL-4Rα signaling in mediating pathological outcomes within the myeloid and airway epithelial cell compartments.

Outcome of SARS-CoV-2 reinfection depends on genetic background in female mice

Antigenically distinct SARS-CoV-2 variants increase the reinfection risk for vaccinated and previously exposed population due to antibody neutralization escape. COVID-19 severity depends on many variables, including host immune responses, which differ depending on genetic predisposition. To address this, we perform immune profiling of female mice with different genetic backgrounds -transgenic K18-hACE2 and wild-type 129S1- infected with the severe B.1.351, 30 days after exposure to the milder BA.1 or severe H1N1. Prior BA.1 infection protects against B.1.351-induced morbidity in K18-hACE2 but aggravates disease in 129S1. H1N1 protects against B.1.351-induced morbidity only in 129S1. Enhanced severity in B.1.351 re-infected 129S1 is characterized by an increase of IL-10, IL-1β, IL-18 and IFN-γ, while in K18-hACE2 the cytokine profile resembles naïve mice undergoing their first viral infection. Enhanced pathology during 129S1 reinfection cannot be attributed to weaker adaptive immune responses to BA.1. Infection with BA.1 causes long-term differential remodeling and transcriptional changes in the bronchioalveolar CD11c+ compartment. K18-hACE2 CD11c+ cells show a strong antiviral defense expression profile whereas 129S1 CD11c+ cells present a more pro-inflammatory response upon restimulation. In conclusion, BA.1 induces cross-reactive adaptive immune responses in K18-hACE2 and 129S1, but reinfection outcome correlates with differential CD11c+ cells responses in the alveolar space.

Notch signaling regulates pulmonary fibrosis

Pulmonary fibrosis is a progressive interstitial lung disease associated with aging. The pathogenesis of pulmonary fibrosis remains unclear, however, alveolar epithelial cell injury, myofibroblast activation, and extracellular matrix (ECM) accumulation are recognized as key contributors. Moreover, recent studies have implicated cellular senescence, endothelial-mesenchymal transition (EndMT), and epigenetic modifications in the pathogenesis of fibrotic diseases. Various signaling pathways regulate pulmonary fibrosis, including the TGF-β, Notch, Wnt, Hedgehog, and mTOR pathways. Among these, the TGF-β pathway is extensively studied, while the Notch pathway has emerged as a recent research focus. The Notch pathway influences the fibrotic process by modulating immune cell differentiation (e.g., macrophages, lymphocytes), inhibiting autophagy, and promoting interstitial transformation. Consequently, inhibiting Notch signaling represents a promising approach to mitigating pulmonary fibrosis. In this review, we discuss the role of Notch signaling pathway in pulmonary fibrosis, aiming to offer insights for future therapeutic investigations.

Immunologic aspects of asthma: from molecular mechanisms to disease pathophysiology and clinical translation

In the present review, we focused on recent translational and clinical discoveries in asthma immunology, facilitating phenotyping and stratified or personalized interventions for patients with this condition. The immune processes behind chronic inflammation in asthma exhibit marked heterogeneity, with diverse phenotypes defining discernible features and endotypes illuminating the underlying molecular mechanisms. In particular, two primary endotypes of asthma have been identified: "type 2-high," characterized by increased eosinophil levels in the airways and sputum of patients, and "type 2-low," distinguished by increased neutrophils or a pauci-granulocytic profile. Our review encompasses significant advances in both innate and adaptive immunities, with emphasis on the key cellular and molecular mediators, and delves into innovative biological and targeted therapies for all the asthma endotypes. Recognizing that the immunopathology of asthma is dynamic and continuous, exhibiting spatial and temporal variabilities, is the central theme of this review. This complexity is underscored through the innumerable interactions involved, rather than being driven by a single predominant factor. Integrated efforts to improve our understanding of the pathophysiological characteristics of asthma indicate a trend toward an approach based on disease biology, encompassing the combined examination of the clinical, cellular, and molecular dimensions of the disease to more accurately correlate clinical traits with specific disease mechanisms.

Activated eosinophils in early life impair lung development and promote long-term lung damage

Exaggeration of type 2 immune responses promotes lung inflammation and altered lung development; however, eosinophils, despite expansion in the postnatal lung, have not been specifically assessed in the context of neonatal lung disease. Furthermore, early life factors including prematurity and respiratory infection predispose infants to chronic obstructive pulmonary disease later in life. To assess eosinophils in the developing lung and how they may contribute to chronic lung disease, we generated mice harboring eosinophil-specific deletion of the negative regulatory enzyme SH2 domain-containing inositol 5' phosphatase-1. This increased the activity and number of pulmonary eosinophils in the developing lung, which was associated with impaired lung development, expansion of activated alveolar macrophages (AMφ), multinucleated giant cell formation, enlargement of airspaces, and fibrosis. Despite regression of eosinophils following completion of lung development, AMφ-dominated inflammation persisted, alongside lung damage. Bone marrow chimera studies showed that SH2 domain-containing inositol 5' phosphatase-1-deficient eosinophils were not sufficient to drive inflammatory lung disease in adult steady-state mice but once inflammation and damage were present, it could not be resolved. Depletion of eosinophils during alveolarization alleviated pulmonary inflammation and lung pathology, demonstrating an eosinophil-intrinsic effect. These results show that the presence of activated eosinophils during alveolarization aggravates AMφs and promotes sustained inflammation and long-lasting lung pathology.

The epithelial era of asthma research: knowledge gaps and future direction for patient care

The Epithelial Science Expert Group convened on 18-19 October 2023, in Naples, Italy, to discuss the current understanding of the fundamental role of the airway epithelium in asthma and other respiratory diseases and to explore the future direction of patient care. This review summarises the key concepts and research questions that were raised. As an introduction to the epithelial era of research, the evolution of asthma management throughout the ages was discussed and the role of the epithelium as an immune-functioning organ was elucidated. The role of the bronchial epithelial cells in lower airway diseases beyond severe asthma was considered, as well as the role of the epithelium in upper airway diseases such as chronic rhinosinusitis. The biology and application of biomarkers in patient care was also discussed. The Epithelial Science Expert Group also explored future research needs by identifying the current knowledge and research gaps in asthma management and ranking them by priority. It was identified that there is a need to define and support early assessment of asthma to characterise patients at high risk of severe asthma. Furthermore, a better understanding of asthma progression is required. The development of new treatments and diagnostic tests as well as the identification of new biomarkers will also be required to address the current unmet needs. Finally, an increased understanding of epithelial dysfunction will determine if we can alter disease progression and achieve clinical remission.

House Dust Mite Proteins Adsorb on Multiwalled Carbon Nanotubes Forming an Allergen Corona That Intensifies Allergic Lung Disease in Mice

The increasing use of multiwalled carbon nanotubes (MWCNTs) could increase the risk of allergic lung disease in occupational or consumer settings. We previously reported that MWCNTs exacerbated allergic lung disease in mice induced by extract from house dust mites (HDM), a common cause of asthma in humans. Because MWCNTs avidly bind biomolecules to form protein coronas that can modify immunotoxicity, we hypothesized that exacerbation of allergic lung disease in mice caused by coexposure to MWCNTs and HDM extract was due to the formation of an allergen corona. In a first set of experiments, male and female C57BL/6J mice were coexposed to MWCNTs and HDM extract over 3 weeks compared to MWCNTs or HDM extract alone. In a second set of experiments, mice were exposed to pristine MWCNTs or MWCNTs with an HDM allergen corona (HDM-MWCNTs). HDM-MWCNTs were formed by incubating MWCNTs with HDM extract, where ∼7% of proteins adsorbed to MWCNTs, including Der p 1 and Der p 2. At necropsy, bronchoalveolar lavage fluid was collected from lungs to assess lactate dehydrogenase, total protein and inflammatory cells, while lung tissue was used for histopathology, qPCR, and Western blotting. Compared to MWCNTs or HDM extract alone, coexposure to MWCNTs and HDM extract or exposure to HDM-MWCNTs increased pathological outcomes associated with allergic lung disease (eosinophilia, fibrosis, mucous cell metaplasia), increased mRNAs associated with fibrosis (Col1A1, Arg1) and enhanced STAT6 phosphorylation in lung tissue. These findings indicated that exacerbation of HDM-induced allergic lung disease by MWCNTs is due to an allergen corona.

In Vivo Exposure of Deltamethrin Dysregulates the NFAT Signalling Pathway and Induces Lung Damage

Deltamethrin is an insecticide used to control harmful agricultural insects that otherwise damage crops and to control vector-borne diseases. Long-term exposure to deltamethrin results in the inflammation of the lungs. The present study elucidates the molecular mechanism underlying the deltamethrin-induced lung damage. The lung samples were extracted from the Swiss albino mice following the treatment of low (2.5 mg/kg) and high (5 mg/kg) doses of deltamethrin. The mRNA expression of TCR, IL-4, and IL-13 showed upregulation, while the expression of NFAT and FOS was downregulated following a low dose of deltamethrin. Moreover, the expression of TCR was downregulated with the exposure of a high dose of deltamethrin. Furthermore, the immunohistochemistry data confirmed the pattern of protein expression for TCR, FOS, IL-4, and IL-13 following a low dose of deltamethrin exposure. However, no change was seen in the TCR, NFAT, FOS, JUN, IL-4, and IL-13 immunopositive cells of the high-dose treatment group. Also, ELISA results showed increased expression of IL-13 in the BAL fluid of animals exposed to low doses of deltamethrin. Overall, the present study showed that deltamethrin exposure induces lung damage and immune dysregulation via dysregulating the NFAT signalling pathway.

The bioflavonoid hispidulin effectively attenuates T helper type 2-driven allergic lung inflammation in the ovalbumin-induced allergic asthma mouse model

BACKGROUND

Allergic asthma affects nearly 300 million people worldwide and causes ahigh burden of disability and death. Effective treatments rely heavily on corticosteroids, which are associated with various complications. So, the alternative treatment is of significance. Hispidulin is a bioflavonoid found in herbs that were used in traditional medicine to treat inflammatory diseases, including asthma. This study aims to investigate the efficacy of hispidulin compound in the treatment of allergic lung inflammation using the mouse model of allergic asthma.

METHODS

BALB/c mice were sensitized and challenged with chicken egg ovalbumin. Cells and cytokines from bronchoalveolar lavage (BAL) fluid were examined. Lung tissues were collected for histologic study. Mouse splenic CD4+ cells were cultured to observe the effect of hispidulin on T-helper 2 (Th2) cell differentiation in vitro.

RESULTS

Hispidulin treatment could alleviate allergic airway inflammation as evidenced by a significant reduction in the inflammatory cell count and Th2 cytokines interleukin (IL)-4, IL-5, IL-13 in BAL fluid. Histologic examination of lung tissues revealed lower inflammatory cell infiltration to the bronchi and less airway goblet cell hyperplasia in the treatment group compared to the control group. At the cellular level, hispidulin (25, 50, and 100 μM) was found to directly suppress the differentiation and proliferation of Th2 cells and to suppress the production of Th2 cytokines, such as IL-4, IL-5, and IL-13, in vitro.

CONCLUSIONS

Hispidulin treatment was shown to effectively decrease type 2 lung inflammation in an ovalbumin-induced allergic asthma mouse model by directly suppressing Th2 cell differentiation and functions.

Mesenchymal Stem Cell-Derived Extracellular Vesicle Therapy for Asthma in Murine Models: A Systematic Review and Meta-analysis

BACKGROUND

Asthma is a common disease, and among the most predominant causes of the years lived with disability. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as a promising avenue for asthma management. The objective of this study is to perform a systematic review and meta-analysis of pre-clinical studies investigating the therapeutic use of MSC-EVs in murine models of asthma.

METHODS

A systematic search of electronic databases was performed. Meta-analyses were conducted on broncho-alveolar lavage fluid (BALF) cells and cytokines, as well as airway hyper-responsiveness Penh values and histological staining scores to determine the efficacy of MSC-EVs-based therapy, comparing treated rodents with untreated ones. BALF IL-4, BALF total cells, and BALF eosinophils were chosen as the primary outcomes, while airway hyper-responsiveness Penh values, BALF cytokines excluding IL-4, and histological staining scores were chosen as secondary outcomes.

RESULTS

A total of 19 eligible studies were included in the current systematic review, with 9 assessing BALF IL-4, 11 assessing BALF total cells, and 10 assessing BALF eosinophils. Pooled Hedges' g (p-value) for each outcome was - 4.407 (< 0.001), -4.976 (< 0.001), and - 4.071 (< 0.001), showing that MSC-EVs therapy inhibits asthma pathology. Changes in secondary outcomes also indicated a reduction in inflammation, goblet cell hyperplasia, and airway hyper-responsiveness. Subgroup analyses did not reveal significant disparities between the type of rodents and administration routes, and meta-regressions were only significant for MSC-EVs source and dose in the IL-4 meta-analysis, and for administration frequency and time from the last challenge to sacrifice in the BALF total cell meta-analysis.

CONCLUSION

This review highlights the current pre-clinical evidence of MSC-EVs therapy for asthma and finds its application ameliorates multiple aspects of asthma's pathology. We further underline the importance of MSC-EVs source, dose, administration frequency, and timing on the therapeutic effect and warrant further investigation and clinical translation to assess the best treatment regimen and to gauge the efficacy of EV therapy in human asthma cases.

Peroxidase-mediated mucin cross-linking drives pathologic mucus gel formation in IL-13-stimulated airway epithelial cells

Mucus plugs occlude airways to obstruct airflow in asthma. Studies in patients and in mouse models show that mucus plugs occur in the context of type 2 inflammation, and studies in human airway epithelial cells (HAECs) show that IL-13-activated cells generate pathologic mucus independently of immune cells. To determine how HAECs autonomously generate pathologic mucus, we used a magnetic microwire rheometer to characterize the viscoelastic properties of mucus secreted under varying conditions. We found that normal HAEC mucus exhibited viscoelastic liquid behavior and that mucus secreted by IL-13-activated HAECs exhibited solid-like behavior caused by mucin cross-linking. In addition, IL-13-activated HAECs shows increased peroxidase activity in apical secretions, and an overlaid thiolated polymer (thiomer) solution shows an increase in solid behavior that was prevented by peroxidase inhibition. Furthermore, gene expression for thyroid peroxidase (TPO), but not lactoperoxidase (LPO), was increased in IL-13-activated HAECs and both TPO and LPO catalyze the formation of oxidant acids that cross-link thiomer solutions. Finally, gene expression for TPO in airway epithelial brushings was increased in patients with asthma with high airway mucus plug scores. Together, our results show that IL-13-activated HAECs autonomously generated pathologic mucus via peroxidase-mediated cross-linking of mucin polymers.

A nationwide study on immunosenescence biomarkers profile in older adults: ELSI-Brazil

Immunosenescence is a phenomenon caused by changes in the immune system, and part of these changes involves an increase in circulating immunological biomarkers, a process known as "Inflammaging." Inflammaging can be associated with many diseases related to older people. As the older population continues to grow, understanding changes in the immune system becomes essential. While prior studies assessing these alterations have been conducted in countries with Caucasian populations, this investigation marks a pioneering effort. The object of the study is to describe for the first time that the distribution of cytokines, chemokines, and growth factors serum levels, assessed by Luminex platform, has been examined in a Brazilian population-based study of older adult females and males by age. Blood samples from 2111 participants (≥50 years old) were analyzed at the baseline (2015/2016) of the ELSI-Brazil study. The exploratory variables considered in the study were age, sex, educational level, residence area, geographic region, alcohol and smoking consumption, physical activity, and self-reported medical diagnoses of hypertension, diabetes, asthma, arthritis, and cancer. The association between serum biomarker levels and age was assessed by a quantile regression model adjusted in the total population and stratified by sex. The significance level considered in the analysis was 0.05. The mean age of the participants was 62.9 years, with a slight majority of female (52.7 %). Differences were found between the sexes in the median circulating levels of the CCL11, CXCL10, and FGF biomarkers. Eight biomarkers showed significant associations with age, including the pro-inflammatory CXCL10, TNF-α, IL-6, IL-17, and IL-2; and type 2/regulatory CCL11 and IL-4, showing positive associations, and anti-inflammatory IL-1Ra showing a negative association. The results suggest similar associations between the sexes, revealing an inflammatory profile characterized by types 1 and 2. Remarkably, these findings reinforce the concept of the Inflammaging process in Brazilian population. These findings add novel insights to about the immunosenescence aspects in middle-income countries and help define biomarkers capable of monitoring inflammation in older adults.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Sex-dependent regulation of mucin gene transcription and airway secretion and mechanics following intra-airway IL-13 in mice with conditional loss of club cell Creb1

Introduction: Interleukin 13 (IL-13) is an important effector molecule in allergic asthma. IL-13-mediated mucin hypersecretion requires conversion of secretoglobin-positive club cells into goblet cells through suppression of forkhead box A2 (FOXA2) and induction of SAM pointed domain containing ETS transcription factor (SPDEF). IL-13-mediated mucin hypersecretion may also include modulation of purinergic and muscarinic receptors that control basal and stimulated mucin secretion. We recently found that the transcription factor cAMP response element-binding protein (Creb1) inhibits FOXA2 and modulates mucus secretion in mice. Methods: We tested the hypothesis that loss of club cell Creb1 mitigates the pro-mucin effects of IL-13. We challenged male and female mice with conditional loss of club cell Creb1 and wild type littermates with intra-airway IL-13 or vehicle. We also studied human "club cell-like" NCI-H322 cells. Results: Loss of club cell Creb1 augmented IL-13-mediated increases in mRNA for the gel-forming mucins Muc5ac and Muc5b and prevented IL-13-mediated decreases in muscarinic 3 receptor (M3R) mRNA in male airways. In female airways, loss of club cell Creb1 reduced M3R mRNA and significantly blunted IL-13-mediated increases in purinergic receptor P2Y2 (P2ry2) mRNA but did not impact Muc5ac and Muc5b mRNA. Despite changes in mucins and secretion machinery, goblet cell density following cholinergic stimulation was not impacted by loss of club cell Creb1 in either sex. IL-13 treatment decreased basal airway resistance across sexes in mice with loss of club cell Creb1, whereas loss of club cell Creb1 augmented IL-13-mediated increases in airway elastance in response to methacholine. NCI-H322 cells displayed IL-13 signaling components, including IL-13Rα1 and IL-4Rα. Pharmacologic inhibition of CREB reduced IL-13Rα1 mRNA, whereas recombinant CREB decreased IL-4Rα mRNA. Application of IL-13 to NCI-H322 cells increased concentrations of cAMP in a delayed manner, thus linking IL-13 signaling to CREB signaling. Conclusion: These data highlight sex-specific regulation of club cell Creb1 on IL-13-mediated mucin hypersecretion and airway mechanics.

CFTR dysfunction leads to defective bacterial eradication on cystic fibrosis airways

Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel by genetic mutations causes the inherited disease cystic fibrosis (CF). CF lung disease that involves multiple disorders of epithelial function likely results from loss of CFTR function as an anion channel conducting chloride and bicarbonate ions and its function as a cellular regulator modulating the activity of membrane and cytosol proteins. In the absence of CFTR activity, abundant mucus accumulation, bacterial infection and inflammation characterize CF airways, in which inflammation-associated tissue remodeling and damage gradually destroys the lung. Deciphering the link between CFTR dysfunction and bacterial infection in CF airways may reveal the pathogenesis of CF lung disease and guide the development of new treatments. Research efforts towards this goal, including high salt, low volume, airway surface liquid acidosis and abnormal mucus hypotheses are critically reviewed.

Distinct fibroblast functions associated with fibrotic and immune-mediated inflammatory diseases and their implications for therapeutic development

Fibroblasts are ubiquitous cells that can adopt many functional states. As tissue-resident sentinels, they respond to acute damage signals and shape the earliest events in fibrotic and immune-mediated inflammatory diseases. Upon sensing an insult, fibroblasts produce chemokines and growth factors to organize and support the response. Depending on the size and composition of the resulting infiltrate, these activated fibroblasts may also begin to contract or relax thus changing local stiffness within the tissue. These early events likely contribute to the divergent clinical manifestations of fibrotic and immune-mediated inflammatory diseases. Further, distinct changes to the cellular composition and signaling dialogue in these diseases drive progressive fibroblasts specialization. In fibrotic diseases, fibroblasts support the survival, activation and differentiation of myeloid cells, granulocytes and innate lymphocytes, and produce most of the pathogenic extracellular matrix proteins. Whereas, in immune-mediated inflammatory diseases, sequential accumulation of dendritic cells, T cells and B cells programs fibroblasts to support local, destructive adaptive immune responses. Fibroblast specialization has clear implications for the development of effective induction and maintenance therapies for patients with these clinically distinct diseases.

Ym1 protein crystals promote type 2 immunity

Spontaneous protein crystallization is a rare event, yet protein crystals are frequently found in eosinophil-rich inflammation. In humans, Charcot-Leyden crystals (CLCs) are made from galectin-10 (Gal10) protein, an abundant protein in eosinophils. Although mice do not encode Gal10 in their genome, they do form pseudo-CLCs, made from the chitinase-like proteins Ym1 and/or Ym2, encoded by Chil3 and Chil4 and made by myeloid and epithelial cells respectively. Here, we investigated the biological effects of pseudo-CLCs since their function is currently unknown. We produced recombinant Ym1 crystals which were shown to have identical crystal packing and structure by X-ray crystallography as in vivo native crystals derived from murine lung. When administered to the airways of mice, crystalline but not soluble Ym1 stimulated innate and adaptive immunity and acted as a type 2 immune adjuvant for eosinophilic inflammation via triggering of dendritic cells (DCs). Murine Ym1 protein crystals found at sites of eosinophilic inflammation reinforce type 2 immunity and could serve as a surrogate model for studying the biology of human CLCs.

Physiological and immunological barriers in the lung

The lungs serve as the primary organ for respiration, facilitating the vital exchange of gases with the bloodstream. Given their perpetual exposure to external particulates and pathogens, they possess intricate protective barriers. Cellular adhesion in the lungs is robustly maintained through tight junctions, adherens junctions, and desmosomes. Furthermore, the pulmonary system features a mucociliary clearance mechanism that synthesizes mucus and transports it to the outside. This mucus is enriched with chemical barriers like antimicrobial proteins and immunoglobulin A (IgA). Additionally, a complex immunological network comprising epithelial cells, neural cells, and immune cells plays a pivotal role in pulmonary defense. A comprehensive understanding of these protective systems offers valuable insights into potential pathologies and their therapeutic interventions.

Inflammatory Markers Involved in the Pathogenesis of Dupuytren's Contracture

Dupuytren's disease is a common fibroproliferative disease that can result in debilitating hand deformities. Partial correction and return of deformity are common with surgical or clinical treatments at present. While current treatments are limited to local procedures for relatively late effects of the disease, the pathophysiology of this connective tissue disorder is associated with both local and systemic processes (e.g., fibrosis, inflammation). Hence, a better understanding of the systemic circulation of Dupuytren related cytokines and growth factors may provide important insights into disease progression. In addition, systemic biomarker analysis could yield new concepts for treatments of Dupuytren that attenuate circulatory factors (e.g., anti-inflammatory agents, neutralizing antibodies). Progress in the development of any disease modifying biologic treatment for Dupuytren has been hampered by the lack of clinically useful biomarkers. The characterization of nonsurgical Dupuytren biomarkers will permit disease staging from diagnostic and prognostic perspectives, as well as allows evaluation of biologic responses to treatment. Identification of such markers may transcend their use in Dupuytren treatment, because fibrotic biological processes fundamental to Dupuytren are relevant to fibrosis in many other connective tissues and organs with collagen-based tissue compartments. There is a wide range of potential Dupuytren biomarker categories that could be informative, including disease determinants linked to genetics, collagen metabolism, as well as immunity and inflammation (e.g., cytokines, chemokines). This narrative review provides a broad overview of previous studies and emphasizes the importance of inflammatory mediators as candidate circulating biomarkers for monitoring Dupuytren's disease.

Phytochemicals as treatment for allergic asthma: Therapeutic effects and mechanisms of action

BACKGROUND

Allergic asthma is an inflammatory disease caused by the immune system's reaction to allergens, inflammation and narrowing of the airways, and the production of more than normal mucus. One of the main reasons is an increased production of inflammatory cytokines in the lungs that leads to the appearance of symptoms of asthma, including inflammation and shortness of breath. On the other hand, it has been proven that phytochemicals with their antioxidant and anti-inflammatory properties can be useful in improving allergic asthma.

PURPOSE

Common chemical treatments for allergic asthma include corticosteroids, which have many side effects and temporarily relieve symptoms but are not a cure. Therefore, taking the help of natural compounds to improve the quality of life of asthmatic patients can be a valuable issue that has been evaluated in the present review.

STUDY DESIGN AND METHODS

In this study, three databases (Scopus, PubMed, and Cochrane) with the keywords: allergic asthma, phytochemical, plant, and herb were evaluated. The primary result was 5307 articles. Non-English, repetitive, and review articles were deleted from the study.

RESULTS AND DISCUSSION

Finally, after carefully reading the articles, 102 were included in the study (2006-2022). The results of this review state that phytochemicals suppress the inflammatory pathways via inhibition of inflammatory cytokines production/secretion, genes, and proteins involved in the inflammation process, reducing oxidative stress indicators and symptoms of allergic asthma, such as cough and mucus production in the lungs.

CONCLUSION

With their antioxidant effects, this study concluded that phytochemicals suppress cytokines and other inflammatory indicators and thus can be considered an adjunctive treatment for improving allergic asthma.

Glucocorticoids, their uses, sexual dimorphisms, and diseases: new concepts, mechanisms, and discoveries

The normal stress response in humans is governed by the hypothalamic-pituitary-adrenal (HPA) axis through heightened mechanisms during stress, raising blood levels of the glucocorticoid hormone cortisol. Glucocorticoids are quintessential compounds that balance the proper functioning of numerous systems in the mammalian body. They are also generated synthetically and are the preeminent therapy for inflammatory diseases. They act by binding to the nuclear receptor transcription factor glucocorticoid receptor (GR), which has two main isoforms (GRα and GRβ). Our classical understanding of glucocorticoid signaling is from the GRα isoform, which binds the hormone, whereas GRβ has no known ligands. With glucocorticoids being involved in many physiological and cellular processes, even small disruptions in their release via the HPA axis, or changes in GR isoform expression, can have dire ramifications on health. Long-term chronic glucocorticoid therapy can lead to a glucocorticoid-resistant state, and we deliberate how this impacts disease treatment. Chronic glucocorticoid treatment can lead to noticeable side effects such as weight gain, adiposity, diabetes, and others that we discuss in detail. There are sexually dimorphic responses to glucocorticoids, and women tend to have a more hyperresponsive HPA axis than men. This review summarizes our understanding of glucocorticoids and critically analyzes the GR isoforms and their beneficial and deleterious mechanisms and the sexual differences that cause a dichotomy in responses. We also discuss the future of glucocorticoid therapy and propose a new concept of dual GR isoform agonist and postulate why activating both isoforms may prevent glucocorticoid resistance.

Th2 Cell Activation in Chronic Liver Disease Is Driven by Local IL33 and Contributes to IL13-Dependent Fibrogenesis

BACKGROUND & AIMS

Type 2 immune responses contribute to liver fibrosis in parasite infections, but their role in other liver diseases is less well understood. Here, we aimed at unravelling mechanisms involved in T helper 2 (Th2) T-cell polarization, activation, and recruitment in human liver fibrosis and cirrhosis.

METHODS

Tissues, cells, and serum from human livers were analyzed using quantitative reverse-transcription polymerase chain reaction, enzyme-linked immunosorbent assay, fluorescence in situ hybridization, immunostaining, flow cytometry, and various functional in vitro assays. Cellular interactions and soluble mediators involved in T-cell polarization and recruitment were studied, as well as their effect on hepatic stellate cell (HSC) activation, proliferation, and extracellular matrix synthesis.

RESULTS

In human liver fibrosis, a stage-dependent increase in Th2-related transcription factors, Th2 cytokines, and trans-acting T-cell-specific transcription factor-expressing T cells was observed, and was highest in cirrhotic livers. The alarmin interleukin (IL)33 was found to be increased in livers and sera from patients with cirrhosis, to act as a chemotactic agent for Th2 cells, and to induce type 2 polarization of CD4+ T cells. Oval cells, liver sinusoidal endothelial cells, intrahepatic macrophages, and migrating monocytes were identified as sources of IL33. IL33-activated T cells, but not IL33 alone, induced HSC activation, as shown by Ki67 and α-smooth muscle actin staining, increased collagen type I alpha 1 chain messenger RNA expression, and wound healing assays. The profibrotic effect of IL33-activated T cells was contact-independent and could be antagonized using monoclonal antibodies against IL13.

CONCLUSION

In patients with chronic liver disease, the alarmin IL33 promotes the recruitment and activation of CD4+ T cells with Th2-like properties, which activate paracrine HSC in an IL13-dependent manner and promotes fibrogenesis.

Host immune responses associated with SARS-CoV-2 Omicron infection result in protection or pathology during reinfection depending on mouse genetic background

Rapid emergence of antigenic distinct SARS-CoV-2 variants implies a greater risk of reinfection as viruses can escape neutralizing antibodies induced by vaccination or previous viral exposure. Disease severity during COVID-19 depends on many variables such as age-related comorbidities, host immune status and genetic variation. The host immune response during infection with SARS-CoV-2 may contribute to disease severity, which can range from asymptomatic to severe with fatal outcome. Furthermore, the extent of host immune response activation may rely on underlying genetic predisposition for disease or protection. To address these questions, we performed immune profiling studies in mice with different genetic backgrounds - transgenic K18-hACE2 and wild-type 129S1 mice - subjected to reinfection with the severe disease-causing SARS-CoV-2 B.1.351 variant, 30 days after experimental milder BA.1 infection. BA.1 preinfection conferred protection against B.1.351-induced morbidity in K18-hACE2 mice but aggravated disease in 129S1 mice. We found that he cytokine/chemokine profile in B.1.351 re-infected 129S1mice is similar to that during severe SARS-CoV-2 infection in humans and is characterized by a much higher level of IL-10, IL-1β, IL-18 and IFN-γ, whereas in B.1.351 re-infected K18-hACE2 mice, the cytokine profile echoes the signature of naïve mice undergoing viral infection for the first time. Interestingly, the enhanced pathology observed in 129S1 mice upon reinfection cannot be attributed to a less efficient induction of adaptive immune responses to the initial BA.1 infection, as both K18-hACE2 and 129S1 mice exhibited similar B and T cell responses at 30 DPI against BA.1, with similar anti-BA.1 or B.1.351 spike-specific ELISA binding titers, levels of germinal center B-cells, and SARS-CoV-2-Spike specific tissue-resident T-cells. Long-term effects of BA.1 infection are associated with differential transcriptional changes in bronchoalveolar lavage-derived CD11c + immune cells from K18-hACE2 and 129S1, with K18-hACE2 CD11c + cells showing a strong antiviral defense gene expression profile whereas 129S1 CD11c + cells showed a more pro-inflammatory response. In conclusion, initial infection with BA.1 induces cross-reactive adaptive immune responses in both K18-hACE2 and 129S1 mice, however the different disease outcome of reinfection seems to be driven by differential responses of CD11c + cells in the alveolar space.

Circular RNAs: emerging players in asthma and COPD

Circular RNAs (circRNAs) belong to a unique class of endogenously expressed non-protein-coding RNAs with a distinct circularized structure, characterized by the absence of 5'-cap and 3'-polyadenylate ends. They are generally formed through back-splicing from pre-mRNAs. They serve as regulators of transcription and splicing, and act as sponges for microRNAs (miRNAs) and RNA-binding proteins, thereby modulating the expression of target genes. As a result, they exert a substantial impact on a diverse array of cellular and biological processes, including cell proliferation, migration, inflammation, and oxidative stress. Asthma and COPD are chronic airway conditions that currently have no cure. In recent years, emerging evidence suggests that altered expression of circRNAs in airway, bronchial and immune cells is involved in asthma and COPD pathogenesis. Studies exploring circRNA dysregulation in asthma have showcased their involvement in regulating the proliferation, migration, and inflammation of airway smooth muscle and bronchial epithelial cells, as well as impacting goblet cell metaplasia, Th2 cell differentiation, and macrophage activation, primarily through interactions with miRNAs. Similarly, in COPD, circRNAs have shown altered expression patterns in the blood and lungs of patients, and these changes have been linked to modulating inflammation, oxidative stress, and airway remodeling in preclinical models. Furthermore, certain circRNAs have demonstrated promising potential as diagnostic and prognostic biomarkers for both asthma and COPD. This review delves into the current understanding of the function and molecular mechanisms of circRNAs in asthma and COPD, along with exploring their potential as biomarkers in these respiratory conditions.

Engineering the IL-4/IL-13 axis for targeted immune modulation

The structurally and functionally related interleukin-4 (IL-4) and IL-13 cytokines play pivotal roles in shaping immune activity. The IL-4/IL-13 axis is best known for its critical role in T helper 2 (Th2) cell-mediated Type 2 inflammation, which protects the host from large multicellular pathogens, such as parasitic helminth worms, and regulates immune responses to allergens. In addition, IL-4 and IL-13 stimulate a wide range of innate and adaptive immune cells, as well as non-hematopoietic cells, to coordinate various functions, including immune regulation, antibody production, and fibrosis. Due to its importance for a broad spectrum of physiological activities, the IL-4/IL-13 network has been targeted through a variety of molecular engineering and synthetic biology approaches to modulate immune behavior and develop novel therapeutics. Here, we review ongoing efforts to manipulate the IL-4/IL-13 axis, including cytokine engineering strategies, formulation of fusion proteins, antagonist development, cell engineering approaches, and biosensor design. We discuss how these strategies have been employed to dissect IL-4 and IL-13 pathways, as well as to discover new immunotherapies targeting allergy, autoimmune diseases, and cancer. Looking ahead, emerging bioengineering tools promise to continue advancing fundamental understanding of IL-4/IL-13 biology and enabling researchers to exploit these insights to develop effective interventions.

Respiratory-syncytial virus immunoprophylaxis on asthma symptoms development in prematurity with bronchopulmonary dysplasia

Background

Infants with respiratory-syncytial virus bronchiolitis hospitalization are more likely to develop wheezing and subsequent asthma. Reportedly, palivizumab prophylaxis effectively prevents respiratory-syncytial virus hospitalization in high-risk children-such as premature infants or infants with bronchopulmonary dysplasia (BPD).

Objective

We sought to explore the effect of respiratory-syncytial virus immunoprophylaxis on the risk of asthma development in premature infants with BPD in subtropical areas.

Methods

This case-control study included preterm children with BPD born at Mackay Memorial Hospital, Taipei, Taiwan, from 1999 to 2015. Overall, medical records of 616 eligible participants were retrospectively collected from their birth to the time they attained an age of 5 to 20 years. The primary outcome was onset of active asthma.

Results

Overall, 576 consecutive cases met the inclusion criteria. Of these, 306 (53.2%) patients had palivizumab exposure and 191 (33.2%) were diagnosed with asthma. Patients with history of respiratory-syncytial virus bronchiolitis hospitalization had a higher risk of developing asthma in the future (adjusted odds ratio, 3.77; 95% CI, 2.30-6.20, P < .001; hazard ratio, 2.56; 95% CI, 1.81-3.62, P < .001). Palivizumab prophylaxis reduced future asthma development through the inhibition of respiratory-syncytial virus bronchiolitis hospitalization (coefficient, -0.021; 95% CI, -0.031 to -0.011, P = .027). Asthmatic children who received palivizumab immunoprophylaxis had a lesser active asthma duration than those who did not (P = .005).

Conclusions

Children with BPD with hospitalization for respiratory-syncytial virus bronchiolitis had higher risk of developing asthma compared with those without respiratory-syncytial virus infection. Prophylactic palivizumab might reduce later asthma development through inhibition of respiratory-syncytial virus bronchiolitis hospitalization. For those already developing asthma, palivizumab could reduce active asthma duration.

The impact of helminth-induced immunity on infection with bacteria or viruses

Different human and animal pathogens trigger distinct immune responses in their hosts. The infection of bacteria or viruses can trigger type I pro-inflammatory immune responses (e.g., IFN-γ, TNF-α, TH1 cells), whereas infection by helminths typically elicits a type II host resistance and tolerizing immune response (e.g., IL-4, IL-5, IL-13, TH2 cells). In some respects, the type I and II immune responses induced by these different classes of pathogens are antagonistic. Indeed, recent studies indicate that infection by helminths differentially shapes the response and outcome of subsequent infection by viruses and bacteria. In this review, we summarize the current knowledge on how helminth infections influence concurrent or subsequent microbial infections and also discuss the implications for helminth-mediated immunity on the outcome of SARS-CoV-2 disease.

Aspirin-exacerbated respiratory disease: Updates in the era of biologics

OBJECTIVE

Aspirin-exacerbated respiratory disease (AERD) is a chronic respiratory condition characterized by severe chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic asthma, and respiratory reactions to cyclooxygenase inhibitors. The management of AERD has evolved recently with the availability of respiratory biologics for treatment of severe asthma and CRSwNP. The objective of this review is to provide an update on the management of AERD in the era of respiratory biologic therapy.

DATA SOURCES

A literature review of pathogenesis and treatment of AERD, with a specific focus on biologic therapies in AERD, was performed through publications gathered from PubMed.

STUDY SELECTIONS

Original research, randomized controlled trials, retrospective studies, meta-analyses, and case series of high relevance are selected and reviewed.

RESULTS

Aspirin therapy after desensitization (ATAD) and respiratory biologic therapies targeting interleukin (IL)-4Rα, IL-5, IL-5Rα, and immunoglobulin E, all have some efficacy in the treatment of CRSwNP and asthma in patients with AERD. There are currently no head-to-head studies comparing ATAD vs respiratory biologic therapy, or specific respiratory biologics, for asthma and CRSwNP in patients with AERD.

CONCLUSION

Advances in our understanding of the fundamental drivers of the chronic respiratory inflammation in asthma and CRSwNP have led to the identification of several potential therapeutic targets for these diseases that can be used in patients with AERD. Further study of the use of ATAD and biologic therapy, independently and together, will help to inform future treatment algorithms for patients with AERD.

Targeting Type 2 Inflammation and Epithelial Alarmins in Chronic Obstructive Pulmonary Disease: A Biologics Outlook

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, progressive inflammatory airway disease associated with a significant impact on patients' lives, including morbidity and mortality, and significant healthcare costs. Current pharmacologic strategies, including first- and second-line therapies such as long-acting β2-agonists, long-acting muscarinic antagonists, inhaled corticosteroids, phosphodiesterase-4 inhibitors, and macrolides, provide relief to patients with COPD. However, many patients remain symptomatic, with persistent symptoms and/or acute exacerbations and progressive lung function loss. Although neutrophilic inflammation is the most common type of inflammation in COPD, 20-40% of patients with COPD exhibit type 2 inflammation, with roles for CD4+ (cluster of differentiation 4) T-helper cell type 1 cells, type 2 innate lymphoid cells, eosinophils, and alternatively activated macrophages. On the basis of the current limitations of available therapies, a significant unmet need exists in COPD management, including the need for targeted therapies to address the underlying pathophysiology leading to disease progression, such as type 2 inflammation, as well as biomarkers to help select the patients who would most benefit from the new therapies. Significant progress is being made, with evolving understanding of the pathobiology of COPD leading to novel therapeutic targets including epithelial alarmins. In this review, we describe the current therapeutic landscape in COPD, discuss unmet treatment needs, review the current knowledge of type 2 inflammation and epithelial alarmins in COPD, explore potential biomarkers of type 2 inflammation in COPD, and finally provide a rationale for incorporating therapies targeting type 2 inflammation and epithelial alarmins in COPD. Video Abstract available online at www.atsjournals.org.

Immunoregulation of asthma by type 2 cytokine therapies: Treatments for all ages?

Asthma is classically considered to be a disease of type 2 immune dysfunction, since many patients exhibit the consequences of excess secretion of cytokines such as IL-4, IL-5, and IL-13 concomitant with inflammation typified by eosinophils. Mouse and human disease models have determined that many of the canonical pathophysiologic features of asthma may be caused by these disordered type 2 immune pathways. As such considerable efforts have been made to develop specific drugs targeting key cytokines. There are currently available multiple biologic agents that successfully reduce the functions of IL-4, IL-5, and IL-13 in patients, and many improve the course of severe asthma. However, none are curative and do not always minimize the key features of disease, such as airway hyperresponsiveness. Here, we review the current therapeutic landscape targeting type 2 immune cytokines and discuss evidence of efficacy and limitations of their use in adults and children with asthma.

Full thickness 3D in vitro conjunctiva model enables goblet cell differentiation

In vitro culture and generation of highly specialized goblet cells is still a major challenge in conjunctival 3D in vitro equivalents. A model comprising all physiological factors, including mucus-secreting goblet cells has the potential to act as a new platform for studies on conjunctival diseases. We isolated primary conjunctival epithelial cells and fibroblasts from human biopsies. 3D models were generated from either epithelial layers or a combination of those with a connective tissue equivalent. Epithelial models were investigated for marker expression and barrier function. Full-thickness models were analyzed for goblet cell morphology and marker expression via immunofluorescence and quantitative real-time PCR. Simple epithelial models cultured at the air-liquid interface showed stratified multi-layer epithelia with pathologic keratinization and without goblet cell formation. The combination with a connective tissue equivalent to generate a full-thickness model led to the formation of a non-keratinized stratified multi-layer epithelium and induced goblet cell differentiation. In our model, a high resemblance to natural conjunctiva was achieved by the combination of conjunctival epithelial cells with fibroblasts embedded in a collagen-hydrogel as connective tissue equivalent. In the future, our conjunctival in vitro equivalent enables the investigation of goblet cell differentiation, conjunctival pathologies as well as drug testing.

Tertiary lymphoid structures in pancreatic cancer: a new target for immunotherapy

Pancreatic cancer (PC) is extremely malignant and shows limited response to available immunotherapies due to the hypoxic and immunosuppressive nature of its tumor microenvironment (TME). The aggregation of immune cells (B cells, T cells, dendritic cells, etc.), which is induced in various chronic inflammatory settings such as infection, inflammation, and tumors, is known as the tertiary lymphoid structure (TLS). Several studies have shown that TLSs can be found in both intra- and peritumor tissues of PC. The role of TLSs in peritumor tissues in tumors remains unclear, though intratumoral TLSs are known to play an active role in a variety of tumors, including PC. The formation of intratumoral TLSs in PC is associated with a good prognosis. In addition, TLSs can be used as an indicator to assess the effectiveness of treatment. Targeted induction of TLS formation may become a new avenue of immunotherapy for PC. This review summarizes the formation, characteristics, relevant clinical outcomes, and clinical applications of TLSs in the pancreatic TME. We aim to provide new ideas for future immunotherapy of PC.

MIF is essential to the establishment of house dust mite-induced airway inflammation and tissue remodeling in mice

Macrophage migration inhibitory factor (MIF) is present in high amounts in the BALF and serum of asthmatic patients, contributing to the pathogenesis of experimental asthma induced by OVA in mice. Whether MIF contributes to the physiopathology on a more complex and relevant asthma model has not been characterized. Mif-deficient (Mif-/- ) or WT mice treated with anti-MIF antibody were challenged multiple times using house dust mite (HDM) extract by the intranasal route. HDM-challenged Mif-/- mice presented decreased airway hyperresponsiveness, lung infiltration of eosinophils, mucus hypersecretion, and subepithelial fibrosis compared to HDM-challenged WT mice. Amounts of IL-4, IL-5, and IL-13 were decreased in the lungs of Mif-/- mice upon HDM challenges, but the increase of CCL11 was preserved, compared to HDM-challenged WT mice. We also observed increased numbers of group 2 innate lymphoid cells and Th2 cells in the BALF and mediastinal LNs (mLN)-induced challenged by HDM of WT mice, but not in HDM-challenged Mif-/- mice. Anti-MIF treatment abrogated the airway infiltration of eosinophils, mucus hypersecretion, and subepithelial fibrosis in the lungs of HDM-challenged mice. In conclusion, MIF ablation prevents the pathologic hallmarks of asthma in HDM-challenged mice, reinforcing the promising target of MIF for asthma therapy.

Cutaneous Exposure to Arsenicals Is Associated with Development of Constrictive Bronchiolitis in Mice

Organoarsenicals, such as lewisite and related chloroarsine, diphenylchloroarsine (DPCA), are chemical warfare agents developed during World War I. Stockpiles in Eastern Europe remain a threat to humans. The well-documented effects of cutaneous exposure to these organoarsenicals include skin blisters, painful burns, and life-threatening conditions such as acute respiratory distress syndrome. In survivors, long-term effects such as the development of respiratory ailments are reported for the organoarsenical sulfur mustard; however, no long-term pulmonary effects are documented for lewisite and DPCA. No animal models exist to explore the relationship between skin exposure to vesicants and constrictive bronchiolitis. We developed and characterized a mouse model to study the long-term effects of cutaneous exposure on the lungs after exposure to a sublethal dose of organoarsenicals. We exposed mice to lewisite, DPCA, or a less toxic surrogate organoarsenic chemical, phenyl arsine oxide, on the skin. The surviving mice were followed for 20 weeks after skin exposure to arsenicals. Lung microcomputed tomography, lung function, and histology demonstrated increased airway resistance, increased thickness of the smooth muscle layer, increased collagen deposition in the subepithelium, and peribronchial lymphocyte infiltration in mice exposed to arsenical on skin.

A four-part guide to lung immunology: Invasion, inflammation, immunity, and intervention

Lungs are important respiratory organs primarily involved in gas exchange. Lungs interact directly with the environment and their primary function is affected by several inflammatory responses caused by allergens, inflammatory mediators, and pathogens, eventually leading to disease. The immune architecture of the lung consists of an extensive network of innate immune cells, which induce adaptive immune responses based on the nature of the pathogen(s). The balance of immune responses is critical for maintaining immune homeostasis in the lung. Infection by pathogens and physical or genetic dysregulation of immune homeostasis result in inflammatory diseases. These responses culminate in the production of a plethora of cytokines such as TSLP, IL-9, IL-25, and IL-33, which have been implicated in the pathogenesis of several inflammatory and autoimmune diseases. Shifting the balance of Th1, Th2, Th9, and Th17 responses have been the targets of therapeutic interventions in the treatment of these diseases. Here, we have briefly reviewed the innate and adaptive i3mmune responses in the lung. Genetic and environmental factors, and infection are the major causes of dysregulation of various functions of the lung. We have elaborated on the impact of inflammatory and infectious diseases, advances in therapies, and drug delivery devices on this critical organ. Finally, we have provided a comprehensive compilation of different inflammatory and infectious diseases of the lungs and commented on the pros and cons of different inhalation devices for the management of lung diseases. The review is intended to provide a summary of the immunology of the lung, with an emphasis on drug and device development.

Human Resistin Induces Cardiac Dysfunction in Pulmonary Hypertension

Background Cardiac failure is the primary cause of death in most patients with pulmonary arterial hypertension (PH). As pleiotropic cytokines, human resistin (Hresistin) and its rodent homolog, resistin-like molecule α, are mechanistically critical to pulmonary vascular remodeling in PH. However, it is still unclear whether activation of these resistin-like molecules can directly cause PH-associated cardiac dysfunction and remodeling. Methods and Results In this study, we detected Hresistin protein in right ventricular (RV) tissue of patients with PH and elevated resistin-like molecule expression in RV tissues of rodents with RV hypertrophy and failure. In a humanized mouse model, cardiac-specific Hresistin overexpression was sufficient to cause cardiac dysfunction and remodeling. Dilated hearts exhibited reduced force development and decreased intracellular Ca2+ transients. In the RV tissues overexpressing Hresistin, the impaired contractility was associated with the suppression of protein kinase A and AMP-activated protein kinase. Mechanistically, Hresistin activation triggered the inflammation mediated by signaling of the key damage-associated molecular pattern molecule high-mobility group box 1, and subsequently induced pro-proliferative Ki67 in RV tissues of the transgenic mice. Intriguingly, an anti-Hresistin human antibody that we generated protected the myocardium from hypertrophy and failure in the rodent PH models. Conclusions Our data indicate that Hresistin is expressed in heart tissues and plays a role in the development of RV dysfunction and maladaptive remodeling through its immunoregulatory activities. Targeting this signaling to modulate cardiac inflammation may offer a promising strategy to treat PH-associated RV hypertrophy and failure in humans.

Biologic Therapies for Asthma and Allergic Disease: Past, Present, and Future

The discovery of the mechanism underlying allergic disease, mouse models of asthma, and bronchoscopy studies provided initial insights into the role of Th2-type cytokines, including interlukin (IL)-4, IL-5 and IL-13, which became the target of monoclonal antibody therapy. Omalizumab, Benralizumab, Mepolizumab, Reslizumab, and Tezepelumab have been approved. These biologicals have been shown to be good alternative therapies to corticosteroids, particularly in severe asthma management, where they can improve the quality of life of many patients. Given the success in asthma, these drugs have been used in other diseases with type 2 inflammation, including chronic rhinosinusitis with nasal polyps (CRSwNP), atopic dermatitis, and chronic urticaria. Like the Th2-type cytokines, chemokines have also been the target of novel monoclonal therapies. However, they have not proved successful to date. In this review, targeted therapy is addressed from its inception to future applications in allergic diseases.