Targeting interleukin-33 and thymic stromal lymphopoietin pathways for novel pulmonary therapeutics in asthma and COPD

Tezepelumab for asthma with current or previous smoking habit: Case series

Tezepelumab effectively treated severe asthma in a current smoker and a former smoker, suggesting that thymic stromal lymphopoietin is involved in the pathogenesis of severe asthma in these patients. Tezepelumab may additionally be used for severe asthma in current and former smokers.

Type 2 inflammation, a common denominator in chronic airway disease?

PURPOSE OF REVIEW

This review addresses the growing understanding that a specific subset of patients with a respiratory disease, including asthma, chronic obstructive pulmonary disease (COPD), or bronchiectasis may have one thing in common: type 2 inflammation. In the era of personalized medicine, we need to refine clinical markers combined with molecular and cellular endotyping to improve patient outcomes.

RECENT FINDINGS

Recent literature reveals that type 2 markers such as blood eosinophils, fractional exhaled nitric oxide (FeNO), and immunglobulin E (IgE), can provide valuable insights into disease progression, exacerbation risk, and treatment response, but their stability remains to be investigated. Treating asthma and COPD patients with biologics to target IL-4/IL-13, IL-5, and alarmins have shown potential, although efficacy varied. In bronchiectasis, a subset of patients with type 2 inflammation may benefit from corticosteroid therapy, despite broader concerns regarding its use.

SUMMARY

This underscores the importance of improved disease endotyping to better characterize patients who may benefit from targeted therapies. In clinical practice, personalized treatment based on inflammatory profiles has been shown to improve outcomes in heterogeneous lung diseases. Future research needs to focus on validating reliable biomarkers and optimizing clinical trial designs to advance therapeutic strategies in respiratory diseases.

The impact of tezepelumab therapy on perceived asthma triggers: a multicenter real-life study

OBJECTIVE

Asthma exacerbations are often triggered by factors such as respiratory infections, allergens, exercise, and airway irritants, significantly affecting patients' respiratory symptoms and quality of life. Effective management of triggers is crucial in severe asthma care. Tezepelumab, an anti-thymic stromal lymphopoietin (TSLP) monoclonal antibody, can effectively reduce severe asthma exacerbations and symptoms burden. However, its impact on patients' perception of trigger-related symptoms remains underexplored.

METHODS

We conducted an observational, multicenter study involving 30 severe asthma patients starting tezepelumab 210 mg every 4 wk. Asthma triggers were assessed with the Asthma Triggers Inventory (ATI), while respiratory symptoms and HRQoL were evaluated using the Asthma Control Test (ACT), Asthma Control Questionnaire (ACQ), and Asthma Quality of Life Questionnaire (AQLQ). Data were collected at baseline (T0) and after 3 months of treatment (T3).

RESULTS

At T3, patients demonstrated a significant reduction in the impact of asthma triggers as well as improvements in the perception of triggers effects on HRQoL. Specific improvements were observed in the "air pollution/irritants" and "infection" domains of the ATI. Correlation analysis revealed a significant association between ATI and AQLQ changes over time.

CONCLUSION

Tezepelumab positively impacts patients' perception of asthma triggers and their HRQoL, supporting its role in managing triggers hypersensitivity as a treatable trait in severe asthma. Further research is warranted to investigate underlying mechanisms and long-term effects.

Challenges and Opportunities in Achieving Asthma Remission

Background: Asthma is a chronic inflammatory disorder in millions of individuals across the globe with high morbidity, mortality, and health care costs. Despite advances in asthma treatment, long-term remission is a challenging target to achieve. Objectives: This review will address the path to remission in asthma with focus on the role of biologic agents in severe asthma management and on the question as to whether long-term disease control and remission are a reality. Methods: A systematic literature review from 1971 to 2025 was conducted through databases such as PubMed, MEDLINE, Scopus, and Web of Science. Clinical trials, meta-analyses, and real-world evidence concerning biologic therapies, such as monoclonal antibodies targeting interleukin -5 (IL-5), IL-4/IL-13, immunoglobulin E, and thymic stromal lymphopoietin, were considered. Symptom control, exacerbation frequency, lung function, and oral corticosteroid (OCS) use were some of the outcomes considered. Results: Biologic treatments have yielded significant gains in asthma control and reduction of exacerbation. Complete remission-long-term resolution of symptoms, inflammation, and drug dependence-is still difficult to achieve. Early intervention with biologics may prevent irreversible airway remodeling, but long-term remission is not in sight. These drugs reduce OCS dependency, but sustainability of remission remains to be investigated. Conclusions: Biologic therapies have advanced asthma treatment, particularly in severe cases, by improving symptoms and reducing exacerbations. However, complete remission remains a distant goal. The development of standardized remission criteria, better patient stratification, and long-term clinical studies are necessary to help achieve sustained asthma control and remission.

The clinical and pathological histology efficacy of biological therapy for severe asthma with a phenotype of type 2 inflammation - systematic review

Asthma is a complex, chronic inflammatory condition of the airways that comes in many forms. Because different inflammatory processes drive it, we can generally categorize asthma into two main types: type 2 inflammatory asthma and non-type 2 inflammatory asthma. Type 2 inflammation is usually the culprit in most folks grappling with severe asthma. There is a noticeable difference in the treatment approaches for different phenotypes of severe asthma. The main reason is that patients suffering from type 2 inflammatory asthma can respond well to treatment with biological agents. Several well-verified biological agents, such as anti-immunoglobulin E (IgE) monoclonal antibodies, anti-interleukin (IL)-4 monoclonal antibodies, anti-IL-5 monoclonal antibodies, and anti-thymic stromal lymphopoietin (TSLP) monoclonal antibodies, have shown outstanding effectiveness. They can significantly alleviate asthma exacerbations, lower the number of eosinophils, improve pulmonary function, decrease the dependence on oral corticosteroids, and elevate the quality of life for patients with asthma. This discourse meticulously evaluates the therapeutic prowess of biological agents in the treatment and control of severe asthma, concurrently investigating their impact on histological indices, to highlight the crucial role of precision medicine in the strategic concatenation of therapy for this refractory malady.

Interleukin-33 modulates NET formation via an autophagy-dependent manner to promote neutrophilic inflammation in cigarette smoke-exposure asthma

Cigarette smoke (CS) contributes to IL---33 release and neutrophil inflammation in asthma. Neutrophil extracellular traps (NETs) are essential for neutrophil function. However, the effect of IL--33 on neutrophils in cigarette smoke--exposure asthma remains unclear. We found that CS exposure led to lower lung function and a neutrophil--related phenotype in asthma, characterized by elevated neutrophil and Th17 cell counts. Granulocytic airway inflammation was ablated by sST2, which blocked excessive IL--33 release. Transcriptome analysis of mouse lungs revealed that IL--33 enhanced NET formation in HDM/CS-treated mice, which was further confirmed in our experimental asthma model and in asthma patients. NETs were associated with poor lung function and airway inflammation and directly facilitated monocyte--derived dendritic cell activation, further inducing Th2/Th17 polarization. Furthermore, we demonstrated a feedforward loop between NETs and neutrophil autophagy, both of which are dependent on reactive oxygen species (ROS) production and the mTOR-Hif-1α signaling pathway. Notably, IL--33 knockout suppressed autophagy and NETs, whereas the autophagy agonist rapamycin reversed the inhibition of NETs by sST2 in a mTOR--dependent manner. Our findings revealed that the IL--33/ST2 signaling pathway interacts with the neutrophil -autophagy--mTOR-Hif-1α-NET pathway, ultimately aggravating Th2/Th17-related inflammation. These insights could lead to potential therapeutic targets for mitigating exacerbations in asthmatic patients who are exposed to CS.

Monoclonal Antibodies for the Treatment of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common and complex disease characterized by persistent airflow limitation and the presence of exacerbations, resulting in significant morbidity and mortality. Although the pathogenesis of COPD is multifactorial, airway inflammation plays a significant role in disease progression. Despite the advantages of non-pharmaceutical and pharmaceutical interventions that have significantly improved the symptom burden and exacerbation frequency in COPD, there is a lack of disease-modifying therapies that target the underlying disease mechanisms. Monoclonal antibodies (mAbs), a drug class that has improved treatment in severe asthma by blocking mediators of the type 2 (Th2) and allergic inflammatory cascades, are currently under investigation for their efficacy in COPD. Our review summarizes the evidence for the use of monoclonal antibodies in COPD and discusses current limitations and promising advances. Although targeting Th1 inflammation has failed to improve COPD outcomes, recent clinical trials have shown beneficial effects of monoclonal antibodies targeting Th2 inflammation, providing evidence for a personalized approach in COPD treatment.

Unraveling asthma through single-cell RNA sequencing in understanding disease mechanisms

OBJECTIVE

To elucidate the fundamental principles of single-cell RNA sequencing (scRNA-seq) and summarize its application in asthma research, aiming to enhance understanding of asthma pathophysiology and guide future research directions.

DATASOURCE

Recent advances and emerging research in scRNA-seq and its role in the pathogenesis of asthma.

STUDY SELECTIONS

This review incorporates studies that analyzed the heterogeneity of asthma cell types and their functional states using scRNA-seq, with particular emphasis on immune cells and airway remodeling. The selection of specific cell types and markers was based on their relevance to asthma pathogenesis, and we discuss the rationale for favoring certain scRNA-seq technologies in these investigations.

RESULTS

ScRNA-seq technology has provided insights into the key mechanisms underlying inflammation and airway remodeling in asthma. It has uncovered the diversity of immune cell subtypes and their specific roles in asthma pathogenesis, revealing critical pathways that contribute to disease progression. These findings offer a theoretical foundation for the development of targeted therapeutic strategies, paving the way for personalized medicine and improved patient outcomes.

CONCLUSION

ScRNA-seq reveals the complex heterogeneity and functional roles of immune cells in asthma, offering key insights into disease mechanisms and the potential for targeted therapies. However, challenges remain, such as the need for further refinement of data integration methods and addressing the limited clinical applicability of current findings. Future research should focus on overcoming these limitations, improving cell type annotation, and expanding studies to include longitudinal and clinical data to better understand disease dynamics and therapy responses.

ERS Congress 2024: highlights from the Airway Diseases Assembly

This article presents highlights from #ERSCongress 2024 from Assembly 5 (airway diseases, asthma, COPD and chronic cough) https://bit.ly/4070nNw.

Defining the Blood Cytokine Profile in Asthma to Understand Asthma Heterogeneity

BACKGROUND

Asthma is a heterogeneous disease characterized by overlapping clinical and inflammatory features.

OBJECTIVE

This study aimed to provide insight into the systemic inflammatory profile in asthma, greater understanding of asthma endotypes and the contribution of genetic risk factors to both.

METHODS

4205 patients with asthma aged 16-60 were recruited from UK centers; serum cytokines were quantified from 708, including cytokines associated with Type 1, 2 and 17 inflammation. 3037 patients were genotyped for 25 single nucleotide polymorphisms associated with moderate-severe asthma.

RESULTS

Serum cytokines associated with Th2 inflammation showed high coordinated expression for example, IL-4/IL-5 (R2 = 0.513). The upper quartile of the serum cytokine data identified 43.7% of patients had high levels for multiple Th2 cytokines. However, the groups defined by serum cytokine profile were not clinically different. Childhood-onset asthma was characterized by elevated total IgE, allergic rhinitis and dermatitis. Exacerbation prone patients had a higher BMI, smoking pack-years, asthma control questionnaire score and reduced lung function. Patients with blood eosinophils of > 300 cells/µL had elevated total IgE and lower smoking pack-years. None of these groups had a differential serum cytokine profile. Asthma risk alleles for; rs61816764 (FLG) and rs9303277 (IKFZ3) were associated with childhood onset disease (p = 2.67 × 10- 4 and 2.20 × 10- 7; retrospectively). No genetic variant was associated with cytokine levels.

CONCLUSION

Systemic inflammation in asthma is complex. Patients had multiple overlapping inflammatory profiles suggesting several disease mechanisms. Genetic risk factors for moderate-severe asthma confirmed previous associations with childhood onset of asthma.

Chronic Inflammation in Asthma: Looking Beyond the Th2 Cell

Asthma is a common chronic inflammatory disease of the airways. A substantial number of patients present with severe and therapy-resistant asthma, for which the underlying biological mechanisms remain poorly understood. In most asthma patients, airway inflammation is characterized by chronic activation of type 2 immunity. CD4+ T helper 2 (Th2) cells are the canonical producers of the cytokines that fuel type 2 inflammation: interleukin (IL)-4, IL-5, IL-9, and IL-13. However, more recent findings have shown that other lymphocyte subsets, in particular group 2 innate lymphoid cells (ILC2s) and type 2 CD8+ cytotoxic T (Tc2) cells, can also produce large amounts of type 2 cytokines. Importantly, a substantial number of severe therapy-resistant asthma patients present with chronic type 2 inflammation, despite the high sensitivity of Th2 cells for suppression by corticosteroids-the mainstay drugs for asthma. Emerging evidence indicates that ILC2s and Tc2 cells are more abundant in severe asthma patients and can adopt corticosteroid-resistance states. Moreover, many severe asthma patients do not present with overt type 2 airway inflammation, implicating non-type 2 immunity as a driver of disease. In this review, we will discuss asthma pathophysiology and focus on the roles played by ILC2s, Tc2 cells, and non-type 2 lymphocytes, placing special emphasis on severe disease forms.

Stellate ganglia block reduces airway hyperresponsiveness with modulates the IKK/NF-κB/IL-4/IL-5/IL-13 pathway

BACKGROUND

Airway hyperresponsiveness (AHR) is characterized by excessive contraction of airway smooth muscle, leading to airflow limitation, increasing perioperative airway spasm and even triggering the defense of silent lungs, which can lead to delayed surgery. Stellate ganglion blockade (SGB) has gained attention for its immunomodulatory and anti-inflammatory effects; however, its impact on AHR and the underlying mechanisms remain unexplored. This study aims to evaluate whether SGB reduces AHR and if this effect is related to inflammation.

METHODS

The experimental groups included Control, OVA (ovalbumin-induced AHR), OVA + SGB2, OVA + SGB4, OVA + SGB5, OVA + SGB6, OVA + SGB8, OVA + 4PBA, Tm, and Tm + SGB6. Mice underwent varying numbers of SGB interventions over 17 days. On day 18, lung function tests were performed, followed by ELISA of IL-4, IL-5, and IL-13 levels in alveolar lavage fluid from the right lung, and finally, tissue from the right lung was extracted for transcriptome analysis, and tissue from the left lung (without lavage fluid) was stained with HE staining to assess histopathological changes.

RESULTS

Compared to the Control group, the OVA group exhibited increased overall respiratory resistance (Rrs), overall respiratory elasticity (Ers), central airway resistance (Rn), peripheral tissue elasticity (H), and tissue damage (G), alongside decreased overall respiratory compliance (Crs) (P < 0.05). SGB significantly improved lung function parameters, with the OVA + SGB6 group showing the most pronounced improvement (P < 0.05). The Tm group displayed elevated Rrs compared to Control (P < 0.05), while the OVA + 4PBA group demonstrated significant improvement in Rrs (P < 0.05). The Tm + SGB6 group also showed significant improvement in Rrs compared to the Tm group (P < 0.05). The expression of IRE1β-IKK/NF-κB genes was upregulated in the OVA group and downregulated in the OVA + SGB6 group. Furthermore, ER stress inhibitors reduced the expression of these key genes in OVA-induced AHR. Notably, the expression of ER stress-related genes was elevated in the OVA group, with a significant decrease in Agr2 (a promoter of ER stress IRE1β) observed in the OVA + SGB6 group compared to the OVA group (114 vs. 16).

CONCLUSION

SGB effectively reduced AHR while down-regulating the expression of key genes in the IKK/NF-κB/IL-4/IL-5/IL-13 signaling pathway, which may be related to IRE1β-mediated endoplasmic reticulum stress. However, further studies are needed to confirm the exact mechanism.

Integrated analysis reveals that EGR1 promotes epithelial IL33 production in T2 asthma

BACKGROUND

Airway epithelial cells constitute the first line of defense against external noxious stimuli and play crucial roles in the release of epithelial inflammatory cytokines (IL33, IL25 and TSLP), initiating airway allergic inflammatory diseases such as asthma. IL33 plays critical physiological processes in T2-endotype asthma. However, the mechanisms by which allergen exposure triggers IL33 release from airway epithelial cells remain unclear.

METHODS

Integrated bioinformatic analysis and transcriptional analysis of bulk RNA-seq and single cell RNA-seq (scRNA-seq) data were used to identify core genes and determine the internal gene network associated with IL33. The expression of EGR1 was subsequently analyzed in vitro in the BEAS-2B cell line and in vivo in a house dust mite (HDM)-induced mouse asthma model. The functional experiments of EGR1 were investigated in vitro via siRNA knockdown and over-expressed plasmid. Chromatin immunoprecipitation (ChIP)-PCR and dual-luciferase reporter assay validation were subsequently performed to investigate the mechanisms by which EGR1 regulates IL33 secretion.

RESULTS

Bulk RNA-seq and scRNA-seq data identified EGR1 as an epithelial cell-derived gene implicated in IL33 expressions in asthma. The comprehensive analysis of multiple datasets indicated that the high EGR1 expression in epithelial cells may suggest a mechanistic basis of T2-endotype childhood asthma. Moreover, we verified that the expressions of EGR1 in airway epithelial cells were elevated both in vitro and in vivo asthma models. EGR1 regulated the production of IL33. Ultimately, ChIP and luciferase reporter assays confirmed that transcription factor EGR1 directly regulate the transcription of IL33 mRNA.

CONCLUSIONS

Our integrated bioinformatic analysis elucidated that EGR1 directly regulates the production of IL33 in T2-asthma and provide insights underlying the progression of asthma.

The extract from Quzhou Aurantii Fructus attenuates cough variant asthma through inhibiting the TRPV1/Ca2+/NFAT/TSLP pathway and ferroptosis via TRPV1 mediation in ovalbumin-induced mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cough variant asthma (CVA), a prevalent chronic inflammatory disease, is the most common cause of chronic cough. Over the years, the aqueous extract of Quzhou Aurantii Fructus (QAFA) has been widely used to treat respiratory diseases, particularly cough.

AIM OF THE STUDY

This study aimed to elucidate the therapeutic effect of QAFA on allergen-induced CVA, providing deep insights into the underlying mechanisms.

MATERIALS AND METHODS

Ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was employed to characterize the compositions, while UPLC was used to quantify the contents of its major components in QAFA. CVA model was established via sensitization and atomization with ovalbumin (OVA), and received 600 and 1200 mg/kg of QAFA via intragastric gavage. Cough response was assessed by stimulation with capsaicin (CAP). Then, airway hyperresponsiveness (AHR), ELISA, western blotting, RT-qPCR, and histological analyses, were applied to assess pulmonary function, pathological changes, and investigate mechanisms in CVA mice following QAFA treatment through the TRPV1/Ca2+-dependent NFAT-induced expression of TSLP and ferroptosis. Additionally, the effects and mechanisms of QAFA were validated using IL-4, CAP for stimulation, capsazepine (CPZ) for inhibition, and TRPV1 siRNA transfection in cells.

RESULTS

Chemical analysis revealed that QAFA primarily contained sixteen compounds, with four main components including narirutin, naringin, hesperidin, and neohesperidin. In vivo, QAFA treatment alleviated cough and AHR, while concurrently reducing airway inflammation and mucus secretion in CVA mice. These effects were achieved by suppressing the TRPV1/NFAT/TSLP pathway and modulating the expression of ferroptosis-related proteins. In vitro, siTRPV1-transfected BEAS-2B cells demonstrated the involvement of the TRPV1 channel in IL-4-mediated Ca2+ influxes, ferroptosis, and regulation of TSLP production. QAFA and CPZ suppressed IL-4-induced TSLP production via the TRPV1/NFAT pathway and regulated the levels of ferroptosis-related proteins, while CAP counteracted the effect of QAFA on TSLP production in BEAS-2B cells. Furthermore, QAFA reduced IL-4 or CAP induced Ca2+ influx and IL-4 induced ferroptosis through TRPV1 mediation.

CONCLUSIONS

This study demonstrated that QAFA improved pulmonary function and alleviated asthmatic inflammatory response in treating CVA probably through suppressing the TRPV1/Ca2+/NFAT/TSLP pathway and ferroptosis via TRPV1 mediation.

IL-33 released during challenge phase regulates allergic asthma in an age-dependent way

Epithelial-derived cytokines, especially type 2 alarmins (TSLP, IL-25, and IL-33), have emerged as critical mediators of type 2 inflammation. IL-33 attracts more interest for its strong association with allergic asthma, especially in childhood asthma. However, the age-dependent role of IL-33 to the development of allergic asthma remains elusive. Here, using OVA-induced allergic asthma model in neonatal and adult mice, we report that IL-33 is the most important alarmin in neonatal lung both at steady state or inflammation. The deficiency of IL-33/ST2 abrogated the development of allergic asthma only in neonates, whereas in adults the effect was limited. Interestingly, the deficiency of IL-33/ST2 equally dampened the ILC2 responses in both neonatal and adult models. However, the effect of IL-33/ST2 deficiency on Th2 responses is age-dependent, which is only blocked in neonates. Furthermore, IL-33/ST2 signaling is dispensable for OVA sensitization. Following OVA challenge in adults, the deficiency of IL-33/ST2 results in compensational more TSLP, which in turn recruits and activates lung DCs and boosts Th2 responses. The enriched γδ T17 cells in IL-33/ST2 deficient neonatal lung suppress the expression of type 2 alarmins, CCL20 and GM-CSF via IL-17A, thus might confer the inhibition of allergic asthma. Finally, on the basis of IL-33 deficiency, the additive protective effects of TSLP blocking is much more pronounced than IL-25 blocking in adults. Our studies demonstrate that the role of IL-33 for ILC2 and Th2 responses varies among ages in OVA models and indicate that the factor of age should be considered for intervention of asthma.

The potential role of nanobodies in asthma therapy

Asthma is a chronic inflammatory disease of the airways characterized by bronchoconstriction, airway hyperresponsiveness, and mucus production. The pathophysiology of asthma involves a complex interplay of immune cells and mediators, including cytokines, chemokines, and other inflammatory molecules. Despite advances in asthma management, many patients continue to experience symptoms due to the limitations of current therapies. Monoclonal antibodies (mAbs) targeting specific inflammatory mediators have improved treatment outcomes for some patients, but challenges such as poor tissue penetration and high costs remain. Nanobodies (Nbs), a novel class of single-domain antibodies, offer a promising alternative due to their small size, stability, and potential for enhanced tissue penetration. This review discusses the key mediators involved in asthma, challenges in current treatments, and the potential of Nbs as a new therapeutic strategy. We also explore current studies and innovations in nanobody technology.

Asthma Biologics Across the T2 Spectrum of Inflammation in Severe Asthma: Biomarkers and Mechanism of Action

Airway inflammation, a hallmark feature of asthma, drives many canonical features of the disease, including airflow limitation, mucus plugging, airway remodeling, and hyperresponsiveness. The T2 inflammatory paradigm is firmly established as the dominant mechanism of asthma pathogenesis, largely due to the success of inhaled corticosteroids and biologic therapies targeting components of the T2 pathway, including IL-4, IL-5, IL-13, and thymic stromal lymphopoietin (TSLP). However, up to 30% of patients may lack signatures of meaningful T2 inflammation (ie, T2 low). In T2-low asthma patients, T2 inflammation may be masked due to anti-inflammatory treatments or may be highly variable depending on exposure to common asthma triggers such as allergens, respiratory infections, and smoke or pollution. The epithelium and epithelial cytokines (TSLP, IL-33) are increasingly recognized as upstream drivers of canonical T2 pathways and as modulators of various effector cells, including mast cells, eosinophils, and neutrophils, which impact the pathological manifestations of airway smooth muscle hypertrophy, hypercontractility, and airway hyperresponsiveness. Approved biologics for severe asthma target several distinct mechanisms of action, leading to differential effects on the spectrum of T2 inflammation, inflammatory biomarkers, and treatment efficacy (reducing asthma exacerbations, improving lung function, and diminishing symptoms). The approved anti-asthma biologics primarily target T2 immune pathways, with little evidence suggesting a benefit of targeting non-T2 asthma-associated mediators. Indeed, many negative results challenge current assumptions about the etiology of non-T2 asthma and raise doubts about the viability of targeting popular alternative inflammatory pathways, such as T17. Novel data have emerged from the use of biologics to treat various inflammatory mediators and have furthered our understanding of pathogenic mechanisms that drive asthma. This review discusses inflammatory pathways that contribute to asthma, quantitatively outlines effects of available biologics on biomarkers, and summarizes data and challenges from clinical trials that address non-T2 mechanisms of asthma.

TSLP acts on regulatory T cells to maintain their identity and limit allergic inflammation

Thymic stromal lymphopoietin (TSLP) is a type I cytokine that promotes allergic responses and mediates type 2 immunity. A balance between effector T cells (Teffs), which drive the immune response, and regulatory T cells (Tregs), which suppress the response, is required for proper immune homeostasis. Here, we report that TSLP differentially acts on Teffs versus Tregs to balance type 2 immunity. As expected, deletion of TSLP receptor (TSLPR) on all T cells (Cd4CreCrlf2fl/fl mice) resulted in lower numbers of T helper 2 (TH2) cells and diminished ovalbumin-induced airway inflammation, but selective deletion of TSLPR on Tregs (Foxp3YFP-Cre/YCrlf2fl/fl mice) resulted in increased interleukin-5 (IL-5)- and IL-13-secreting TH2 cells and lung eosinophilia. Moreover, TSLP augmented the expression of factors that stabilize Tregs. During type 2 immune responses, TSLPR-deficient Tregs acquired TH2-like properties, with augmented GATA3 expression and secretion of IL-13. TSLP not only is a driver of TH2 effector cells but also acts in a negative feedback loop, thus promoting the ability of Tregs to limit allergic inflammation.

TSLP and TSLPr Expression and Localization in the Airways of COPD and Non-COPD Patients

Thymic stromal lymphopoietin (TSLP) is an alarmin cytokine activated by allergens, pathogens, and air pollutants. Recent studies suggest TSLP dysregulation in chronic inflammatory diseases. It was highlighted as a key player in the context of asthma-associated mucosal immunity. This study investigated the production and localization of TSLP and its receptors in airway epithelial cells and the related inflammatory response in chronic obstructive pulmonary disease (COPD) and non-COPD patients. TSLP transcripts and proteins were detected in epithelial cells but were not abundant at a steady state. The secretion of airway inflammatory mediators was altered in COPD in association with TSLP production. The cellular and molecular characterization of TSLP signaling may identify COPD patients that could benefit from anti-alarmin therapeutic approaches.

The Presence and Pathogenic Roles of M(IL-33 + IL-2) Macrophages in Allergic Airway Inflammation

BACKGROUND

Macrophages, one of the most abundant immune cells in the lung, have drawn great attention in allergic asthma. Currently, most studies emphasize alternative activated (M2) polarization bias. However, macrophage function in allergic asthma is still controversial. Interleukin (IL)-9 contributes to the development and pathogenesis of allergic airway inflammation. We sought to investigate the IL-9-producing macrophage and its role in allergic asthma.

METHODS

The model of ovalbumin (OVA)-induced allergic airway inflammation was employed to evaluate IL-9 production in macrophages of lung tissues. We used 22 cytokines or stimuli to screen for IL-9-producing mouse macrophage subset in vitro. Real-time PCR, flow cytometry, ELISA, and RNA-seq to explore the subset. Conditional IL-33 receptor knockout (Lyz-ST2KO) mice and cellular adoptive transfer experiment were used to characterize the potential roles of M(IL-33 + IL-2) in allergic asthma.

RESULTS

We identified a unique pathogenic IL-9-producing macrophage in OVA-induced allergic airway inflammation. We found that only IL-33 significantly induced IL-9 production in mouse macrophages, and IL-2 collaborated with IL-33 to promote IL-9 production, referred to as M(IL-33 + IL-2). Importantly, human monocyte-derived macrophages produced IL-9 after IL-33 and IL-2 stimulation. Using Lyz-ST2KO mice and adoptive transfer of M(IL-33 + IL-2), we found that M(IL-33 + IL-2) significantly promoted pathogenesis in OVA-induced allergic airway inflammation. M(IL-33 + IL-2) has a distinctive gene expression profile with high expression of IL-9, IL-5, and IL-13 and its polarization is dependent on JAK2-STAT3-IRF1 pathway.

CONCLUSIONS

The identification of M(IL-33 + IL-2) subset extends the diversity and heterogeneity of macrophage subsets and may offer novel therapeutic strategies for the treatment of allergic inflammation.

A novel monoclonal antibody against human thymic stromal lymphopoietin for the treatment of TSLP-mediated diseases

Introduction

Thymic stromal lymphopoietin (TSLP) is a master regulator of allergic inflammation against pathogens at barrier surfaces of the lung, skin, and gut. However, aberrant TSLP activity is implicated in various allergic, chronic inflammation and autoimmune diseases and cancers. Biologics drugs neutralizing excess TSLP activity represented by tezepelumab have been approved for severe asthma and are being evaluated for the treatments of other TSLP-mediated diseases.

Methods and results

In this study, we discovered and characterized a novel humanized anti-TSLP antibody TAVO101 with high binding affinity to human TSLP, which blocks TSLP binding to its receptor complexes on cell surface. TAVO101 showed potent neutralization of TSLP activities in the TSLP-driven STAT5 reporter assay and cell proliferation assay. Results from ex vivo studies showed that TAVO101 neutralized TSLP-mediated CCL17 release from primary human CD1c+ dendritic cells and proliferation of activated CD4+ T cells. In addition, TAVO101 showed strong efficacy in both TSLP/OVA-induced asthma and imiquimod induced psoriasis models in hTSLP/hTSLPR double knock-in mice. We further conducted Fc engineering to optimize TAVO101 antibody with reduced affinity to Fcγ receptors and C1q protein but with increased affinity to FcRn receptor for half-life extension.

Discussion

By recognizing a different epitope, similarly potent neutralization of TSLP activities, and longer circulating half-life than tezepelumab, novel anti-TSLP antibody TAVO101 offers a potential best-in class therapeutics for various TSLP-mediated diseases.

Elucidating the beneficial impact of exercise on chronic obstructive pulmonary disease and its comorbidities: Integrating proteomic and immunological insights

BACKGROUND AND PURPOSE

Physical activity is an effective therapeutic protocol for treating chronic obstructive pulmonary disease (COPD). However, the mechanisms underlying the benefits of physical activity in COPD are not fully elucidated.

EXPERIMENTAL APPROACH

In a mouse model of COPD, analysis of biological markers and lung proteomics identified the molecular pathways through which exercise ameliorates COPD.

KEY RESULTS

Exercise improved pulmonary function, emphysema, small airway disease, pulmonary inflammation, glucose metabolic dysregulation, and insulin resistance in COPD mice. Proteomic analysis revealed 430 differentially expressed proteins (DEPs) between the COPD and COPD + Exercise (COPD + Ex) groups. GO analysis indicated that the enriched pathways were predominantly related to the immune response, inflammatory processes, insulin secretion, and glucose metabolic processes. GO analysis revealed IL-33 as a crucial target for the exercise-related amelioration of COPD. KEGG analysis showed that DEPs were significantly enriched in primary immunodeficiency, the intestinal immune network for IgA production, and the NF-κB signalling pathway. Exercise inhibited NF-κB activation by suppressing the CD14/TLR4/MyD88 and TNF-α/TNF-R1/TRAF2/5 pathways in COPD mice. Exercise inhibited expression of BCR, IgM, IgD, IgG, IgE, and IgA by suppressing B-cell receptor signalling. Exercise attenuated glucose metabolic dysregulation and insulin resistance through the suppression of proinflammatory mediators, including MHC I, MHC II, TNF-α, IFN-γ, and IL-1β, while concurrently increasing insulin expression. The qRT-PCR results were consistent with the proteomic results.

CONCLUSION AND IMPLICATIONS

In a mouse model, exercise improved COPD and its metabolic comorbidities through immune system regulation and inflammation suppression, offering insights into potential therapeutic targets.

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

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

The relevance of eosinophils in chronic obstructive pulmonary disease: inflammation, microbiome, and clinical outcomes

Chronic obstructive pulmonary disease is caused by the inhalation of noxious particles such as cigarette smoke. The pathophysiological features include airway inflammation, alveolar destruction, and poorly reversible airflow obstruction. A subgroup of patients with chronic obstructive pulmonary disease has higher blood eosinophil counts, associated with an increased response to inhaled corticosteroids and increased biomarkers of pulmonary type 2 inflammation. Emerging evidence shows that patients with chronic obstructive pulmonary disease with increased pulmonary eosinophil counts have an altered airway microbiome. Higher blood eosinophil counts are also associated with increased lung function decline, implicating type 2 inflammation in progressive pathophysiology in chronic obstructive pulmonary disease. We provide a narrative review of the role of eosinophils and type 2 inflammation in the pathophysiology of chronic obstructive pulmonary disease, encompassing the lung microbiome, pharmacological targeting of type 2 pathways in chronic obstructive pulmonary disease, and the clinical use of blood eosinophil count as a chronic obstructive pulmonary disease biomarker.

Pharmacokinetics of Subcutaneous Itepekimab Injection With an Autoinjector Device and Prefilled Syringe in Healthy Participants

Itepekimab, a monoclonal antibody against interleukin-33, has demonstrated clinical utility in previous studies in patients with asthma and chronic obstructive pulmonary disease. An autoinjector (AI) has been developed for administering itepekimab to facilitate further development. This study compared pharmacokinetics of single 300-mg itepekimab subcutaneous administration via an AI versus a prefilled syringe (PFS). Of 90 healthy volunteers enrolled in this Phase 1, parallel-design, randomized study and stratified by body weight (50 to <70 kg, ≥70 to <80 kg, ≥80 to 100 kg) and injection site (abdomen, thigh, or arm), 84 completed the study. Systemic exposure of itepekimab was similar for both groups. Point estimates for geometric mean ratios of pharmacokinetic parameters for AI versus PFS groups were 1.01 for maximum serum concentration, 1.06 for area under the serum concentration-time curve to the last quantifiable concentration, and 1.04 for area under the serum concentration-time curve extrapolated to infinity. The exposure was similar for both devices in each body weight and injection site subgroup. Overall, systemic exposure of 300-mg single-dose itepekimab in healthy participants was comparable when administered subcutaneously via an AI device and PFS, with an acceptable safety profile in both device groups.

Biologics in Asthma: Emerging Biologics

Advances in our understanding of asthma pathophysiology have led to the advent of multiple targeted asthma therapies such as biologics. However, partial response to biologics occurs, indicating residual disease activity in some patients. Hence, there exists a need for new therapies that focus on novel pathways, alongside perhaps evaluation of combination biologic therapies and modulators of downstream cytokine activation. Therefore, although our current focus is on biologics; it is critical to take a more holistic approach including consideration for nonbiologic therapies that have the potential to significantly advance asthma care.

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.

[Assessment of blood eosinophil count in respiratory disease from primary care]

Most physicians in general, and family physicians in particular, are familiar with certain parameters when ordering a hematological study, such as hemoglobin (including hematocrit and its features), leukocytes (including lymphocytes) and platelets. Nevertheless, there are two values that we use to overlook which are eosinophils and basophils. Specifically, eosinophils have a tendency to increase with allergic pathology. This article focuses on this type of cells, helping to interpret the values obtained and highlighting their importance in two of the most frequent respiratory pathologies in primary care: asthma and COPD. In addition to observing how the increase or normality of these parameters condition the diagnosis, phenotype and even the treatment.

Towards precision medicine in COPD: Targeting type 2 cytokines and alarmins

Chronic obstructive pulmonary disease (COPD) is a main global epidemic increasing as population age and affecting approximately 10% of subjects over 45 years. COPD is a heterogeneous inflammatory disease with several endo-phenotypes and clinical presentations. Although neutrophilic inflammation is canonically considered a hallmark of COPD, eosinophilic inflammation can also be present in a subgroup of patients. Several other immune cells and cytokines play a key role in orchestrating and perpetuating the inflammatory pathways in COPD, making them attractive targets for treating this disorder. Recent studies have started to evaluate the possible role of type 2 (T2) inflammation and epithelial-derived alarmins (TSLP and IL-33) in COPD. Two phase III randomized clinical trials (RCTs) showed a modest reduction in exacerbations in COPD patients with eosinophilic phenotype treated with mepolizumab (anti-IL-5) or benralizumab (anti-IL-5Rα). A phase III RCT showed a 30% reduction in exacerbations in COPD patients with ≥ 300 eosinophils/μL treated with dupilumab (anti-IL-4Rα). These results suggest that blocking a single cytokine (e.g., IL-5) or its main target (i.e., IL-5Rα) is less promising than blocking a wider spectrum of cytokines (i.e., IL-4 and IL-13) in COPD. TSLP and IL-33 are upstream regulators of T2-high and T2-low immune responses in airway inflammation. Several ongoing RCTs are evaluating the efficacy and safety of anti-TSLP (tezepelumab), anti-IL-33 (itepekimab, tozorakimab), and anti-ST2 (astegolimab) in patients with COPD, who experience exacerbations. In conclusion, targeting T2 inflammation or epithelial-derived alarmins might represent a step forward in precision medicine for the treatment of a subset of COPD.

Clinical Remission Criteria and Serum Levels of Type 2 Inflammation Mediators during 24 Weeks of Treatment with the Anti-IL-5 Drug Mepolizumab in Patients with T2-High Severe Asthma

Anti-interleukin (IL) 5 is an effective treatment modality for inhibiting eosinophilic inflammation in patients with T2-high severe asthma. The aim of this study was to determine the clinical efficacy and serum levels of type 2 inflammatory mediators during 24 weeks of mepolizumab treatment in patients with T2-high severe asthma. Eighteen patients with T2-high severe asthma were enrolled in this study. All patients received 100 mg of mepolizumab subcutaneously every 4 weeks and were retested at 4, 12, and 24 weeks. A clinical examination, asthma control test (ACT), and spirometry were performed; fractional exhaled nitric oxide (FeNO) levels were evaluated; and blood samples were drawn at every visit. Type 2 inflammation mediator levels were measured using enzyme-linked immunosorbent assay (ELISA). The blood eosinophil level significantly decreased, the ACT score and FEV1 increased after 4 weeks of mepolizumab treatment with the same tendency after 12 and 24 weeks (p < 0.05), and the FeNO level did not change (p > 0.05). A total of 27.8% of patients reached clinical remission criteria after 24 weeks of mepolizumab treatment. IL-33 and eotaxin significantly increased (p < 0.05) while IL-5, IL-13, thymic stromal lymphopoietin (TSLP), soluble IL-5 receptor subunit alpha (sIL-5Rα), and soluble high-affinity immunoglobulin E receptor (sFcεRI) decreased, with the same tendency after 12 and 24 weeks (p < 0.05). The serum levels of immunoglobulin (Ig) E and IL-4 and IL-25 levels did not change during mepolizumab treatment compared to baseline (p > 0.05). In conclusion, treatment with mepolizumab over 24 weeks improved lung function and asthma control in T2-high severe asthma patients, with nearly one-third achieving clinical remission criteria, and affected the balance of type 2 inflammatory mediators.

[Take-home messages from the 2nd COPD 2023 Biennial of the French Society of Respiratory Diseases. Placing the patient at the center of the care pathway]

INTRODUCTION

The second COPD Biennial organized by the COPD working group of the French Society of Respiratory Diseases took place in Paris (Cochin) on 13th December 2023.

STATE OF THE ART

Major trends in 2023 were discussed; they encompassed concepts, definitions, biologics, care pathways, pulmonary rehabilitation and complex situations entailed by respiratory infections, cardiovascular comorbidities and pulmonary hypertension, and modalities of oxygen therapy and ventilation.

PERSPECTIVES

The different talks underlined major changes in COPD including the concepts of pre-COPD, etiotypes, health trajectories and new definitions of exacerbation. Recent results in biologics for COPD open the door to new pharmacological options. Assessment of current care pathways in France highlighted some causes for concern. For example, pulmonary rehabilitation is a key but insufficiently practiced element. Respiratory infections require careful assessment and treatments. Diagnosis and treatment of cardiovascular comorbidities and pulmonary hypertension are of paramount importance. As of late, oxygen therapy and ventilation modalities have evolved, and are beginning to afford more personalized options.

CONCLUSIONS

As regards COPD, a personalized approach is crucial, placing the patient at the center of the care pathway and facilitating coordination between healthcare providers.

Interleukin-33/serum stimulation-2 pathway: Regulatory mechanisms and emerging implications in immune and inflammatory diseases

Interleukin (IL)- 33, a nuclear factor and pleiotropic cytokine of the IL-1 family, is gaining attention owing to its important role in chronic inflammatory and autoimmune diseases. This review extends our knowledge of the effects exerted by IL-33 on target cells by binding to its specific receptor serum stimulation-2 (ST2). Depending on the tissue context, IL-33 performs multiple functions encompassing host defence, immune response, initiation and amplification of inflammation, tissue repair, and homeostasis. The levels and activity of IL-33 in the body are controlled by complex IL-33-targeting regulatory pathways. The unique temporal and spatial expression patterns of IL-33 are associated with host homeostasis and the development of immune and inflammatory disorders. Therefore, understanding the origin, function, and processes of IL-33 under various conditions is crucial. This review summarises the regulatory mechanisms underlying the IL-33/ST2 signalling axis and its potential role and clinical significance in immune and inflammatory diseases, and discusses the current complex and conflicting findings related to IL-33 in host responses.

Thymic stromal lymphopoietin contributes to ozone-induced exacerbations of eosinophilic airway inflammation via granulocyte colony-stimulating factor in mice

BACKGROUND

Ozone is one of the triggers of asthma, but its impact on the pathophysiology of asthma, such as via airway inflammation and airway hyperresponsiveness (AHR), is not fully understood. Thymic stromal lymphopoietin (TSLP) is increasingly seen as a crucial molecule associated with asthma severity, such as corticosteroid resistance.

METHODS

Female BALB/c mice sensitized and challenged with house dust mite (HDM) were exposed to ozone at 2 ppm for 3 h. Airway inflammation was assessed by the presence of inflammatory cells in bronchoalveolar lavage fluid and concentrations of cytokines including TSLP in lung. Anti-TSLP antibody was administered to mice to block the signal. Survival and adhesion of bone marrow-derived eosinophils in response to granulocyte colony-stimulating factor (G-CSF) were evaluated.

RESULTS

Ozone exposure increased eosinophilic airway inflammation and AHR in mice sensitized and challenged with HDM. In addition, TSLP, but not IL-33 and IL-25, was increased in lung by ozone exposure. To confirm whether TSLP signaling is associated with airway responses to ozone, an anti-TSLP antibody was administered, and it significantly attenuated eosinophilic airway inflammation, but not AHR. Interestingly, G-CSF, but not type 2 cytokines such as IL-4, IL-5, and IL-13, was regulated by TSLP signaling associated with eosinophilic airway inflammation, and G-CSF prolonged survival and activated eosinophil adhesion.

CONCLUSIONS

The present data show that TSLP contributes to ozone-induced exacerbations of eosinophilic airway inflammation and provide greater understanding of ozone-induced severity mechanisms in the pathophysiology of asthma related to TSLP and G-CSF.

Chaenomeles sinensis Extract Ameliorates Ovalbumin-Induced Allergic Rhinitis by Inhibiting the IL-33/ST2 Axis and Regulating Epithelial Cell Dysfunction

Chaenomeles sinensis has traditionally been used as an herbal medicine due to its characteristics that protect against inflammation, hypertension, and mutagenesis. However, the effect of Chaenomeles sinensis extract (CSE) on allergic rhinitis (AR) and its underlying mechanisms have yet to be thoroughly investigated. The current study explored the likely effect of CSE on AR in an ovalbumin (OVA)-induced AR mouse model. To this end, OVA-specific immunoglobulins, nasal symptoms, cytokine production, the infiltration of inflammatory cells, and nasal histopathology were assessed to determine the role of CSE against AR. The supplementation of CSE was found to suppress OVA-specific IgE, while OVA-specific IgG2a was increased in the serum. Further, CSE ameliorated the production of T helper type 2 (Th2) cytokines whereas it increased Th1 cytokine levels in nasal lavage fluid. Moreover, the CSE treatment group exhibited significant inhibition of IL-33/ST2 signaling. Subsequently, CES reversed the OVA-induced enhancement of epithelial permeability and upregulated E-cadherin, thus indicating that CES plays a protective role on epithelial barrier integrity. Altogether, the oral administration of CSE effectively controlled allergic response by restricting the buildup of inflammatory cells, enhancing nasal and lung histopathological traits, and regulating cytokines associated with inflammation. Collectively, the results show that the supplementation of CSE at different doses effectively regulated AR, thus suggesting the therapeutic efficiency of CSE in suppressing airway diseases.

P2X7 Receptor-Induced Human Mast Cell Degranulation Is Enhanced by Interleukin 33

MCs are tissue-resident immune cells that strategically reside in barrier organs and respond effectively to a wide range of stimuli, such as IL-33, a mediator released upon epithelial damage. Adenosine triphosphate (ATP) accumulates at sites of tissue injury and is known to modulate MC activities. This study investigated how an inflammatory tissue environment rich in IL-33 modulates the ATP-mediated activation of MCs. Human primary MCs primed with IL-33 displayed a strongly increased response to ATP but not ADP. This resulted in increased degranulation, IL-8 release, and pERK1/2 signalling. Such effects are unique to IL-33 stimulation and not shared by the epithelial alarmin, TSLP. MC exposure to IL-33 also increased membrane expression of purinergic and ATP-binding P2X receptors. The use of selective P2X receptor inhibitors identified P2X7 receptor as the key mediator of the enhanced ATP-induced ERK1/2 signalling and degranulation in IL-33-primed MCs. Whilst the inhibition of P2X1 and P2X4 receptors had no effect on MC degranulation, inhibiting these receptors together with P2X7 resulted in further decreased MC-mediated degranulation. These data therefore point toward the potential mechanisms by which IL-33 contributes to the modulation of ATP-mediated activation in human MCs.

Daqing formula ameliorated allergic asthma and airway dysbacteriosis in mice challenged with ovalbumin and ampicillin

ETHNOPHARMACOLOGICAL RELEVANCE

Asthma is a chronic airway inflammatory disease that can lead to several complications caused by bacterial infections. However, recurrent attacks of the disease require long-term use of antibiotics, resulting in lung dysbiosis and poor outcomes. Daqing Formula (DQF) is a well-known herbal medicine in Pharmacopoeia of China, which is widely used for various stimuli-induced lower respiratory diseases, including asthma, bronchitis, and pneumonia. Thus, it has been demonstrated to be a plant-derived broad-spectrum antibiotic for treating and preventing various acute and chronic respiratory diseases.

AIM OF THE STUDY

This study evaluated the efficacy and possible mechanism of DQF on allergic asthma and airway dysbiosis.

METHODS AND MATERIALS

The mice were co-challenged with ovalbumin and ampicillin to induce allergic asthma combined with airway dysbacteriosis. The populations of lung microbiota were detected by using 16s DNA sequencing. The levels of asthmatic markers in BALF were detected by ELISA. The levels of Th1/Th2 cytokines in splenic CD4+ cells of mice were analyzed by flow cytometry. The expressions of the GSK-3β signaling pathway in the lung tissues of asthmatic mice and eosinophils were detected by western blotting assay. The inhibition of DQF on the production of pro-inflammatory cytokines in eosinophils of asthmatic mice.

RESULTS

The results showed that treatment with DQF at 200-800 mg/kg doses significantly reduced the frequency of nasal rubbing and lung inflammation as well as the number of total cells, eosinophils, and macrophages in bronchoalveolar lavage fluid. It decreased the relative abundances of Streptococcus, Cuoriavidus, and Moraxella, increased Akkermansia and Prevotella_6 in lung tissues of asthmatic mice, and inhibited the growth of Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae and their resistant strains in vitro. Furthermore, DQF reduced the levels of eotaxin, TSLP, IL-4, IL-5, IL-25, and IL-33, but enhanced IFN-γ and IL-12 in BALF. It elevated the population of Th1 cells, inhibited eosinophil activation, and downregulated the expressions of p-GSK-3β, p-p65, nuclear β-catenin, and p-STAT3 in the lung tissues of asthmatic mice.

CONCLUSIONS

The results revealed that DQF reduced airway inflammation, ameliorated lung dysbiosis, shifted the Th1/Th2 balance, and inhibited eosinophil activation in asthmatic mice, indicating its potential for severe asthma treatment.

A conversation on allergy: recognizing the past and looking to the future

Allergy is an ever-evolving group of disorders, which includes asthma, atopic dermatitis, rhinitis and food allergies and that currently affects over 1 billion people worldwide. This group of disorders has exploded in incidence since around the start of the 20th century, implying that genetics is not solely responsible for its development but that environmental factors have an important role. Here, Fabio Luciani and Jonathan Coquet, in their role as editors at Immunology & Cell Biology, asked nine prominent researchers in the field of allergy to define the term 'allergy', discuss the role of genetics and the environment, nominate the most important discoveries of the past decade and describe the best strategies to combat allergy at the population level going forward.

Epidemiology and Immunopathogenesis of Virus Associated Asthma Exacerbations

Asthma is a common airway disease, affecting millions of people worldwide. Although most asthma patients experience mild symptoms, it is characterized by variable airflow limitation, which can occasionally become life threatening in the case of a severe exacerbation. The commonest triggers of asthma exacerbations in both children and adults are viral infections. In this review article, we will try to investigate the most common viruses triggering asthma exacerbations and their role in asthma immunopathogenesis, since viral infections in young adults are thought to trigger the development of asthma either right away after the infection or at a later stage of their life. The commonest viral pathogens associated with asthma include the respiratory syncytial virus, rhinoviruses, influenza and parainfluenza virus, metapneumovirus and coronaviruses. All these viruses exploit different molecular pathways to infiltrate the host. Asthmatics are more prone to severe viral infections due to their unique inflammatory response, which is mostly characterized by T2 cytokines. Unlike the normal T1 high response to viral infection, asthmatics with T2 high inflammation are less potent in containing a viral infection. Inhaled and/or systematic corticosteroids and bronchodilators remain the cornerstone of asthma exacerbation treatment, and although many targeted therapies which block molecules that viruses use to infect the host have been used in a laboratory level, none has been yet approved for clinical use. Nevertheless, further understanding of the unique pathway that each virus follows to infect an individual may be crucial in the development of targeted therapies for the commonest viral pathogens to effectively prevent asthma exacerbations. Finally, biologic therapies resulted in a complete change of scenery in the treatment of severe asthma, especially with a T2 high phenotype. All available data suggest that monoclonal antibodies are safe and able to drastically reduce the rate of viral asthma exacerbations.

Contributions of the early-life microbiome to childhood atopy and asthma development

The rapid rise in atopy and asthma in industrialized nations has led to the identification of early life environmental factors that promote these conditions and spurred research into how such exposures may mediate the trajectory to childhood disease development. Over the past decade, the human microbiome has emerged as a key determinant of human health. This is largely due to the increasing appreciation for the myriad of non-mutually exclusive mechanisms by which microbes tune and train host immunity. Microbiomes, particularly those in early life, are shaped by extrinsic and intrinsic factors, including many of the exposures known to influence allergy and asthma risk. This has led to the over-arching hypothesis that such exposures mediate their effect on childhood atopy and asthma by altering the functions and metabolic productivity of microbiomes that shape immune function during this critical developmental period. The capacity to study microbiomes at the genetic and molecular level in humans from the pre-natal period into childhood with well-defined clinical outcomes, offers an unprecedented opportunity to identify early-life and inter-generational determinants of atopy and asthma outcomes. Moreover, such studies provide an integrative microbiome research framework that can be applied to other chronic inflammatory conditions. This review attempts to capture key studies in the field that offer insights into the developmental origins of childhood atopy and asthma, providing novel insights into microbial mediators of maladaptive immunity and chronic inflammatory disease in childhood.

Epithelial alarmins: a new target to treat chronic respiratory diseases

INTRODUCTION

In response to injury, epithelial cells release alarmins including thymic stromal lymphopoietin (TSLP), high mobility group-box-1 (HMGB1), interleukin (IL)-33 and -25 that can initiate innate immune responses. These alarmins are recognized as activators of T2-immune responses characteristic for asthma, but recent evidence highlighted their role in non-T2 inflammation, airway remodeling, and pulmonary fibrosis making them an attractive therapeutic target for chronic respiratory diseases (CRD).

AREAS COVERED

In this review, firstly we discuss the role of TSLP, IL-33, IL-25, and HMGB1 in the pathogenesis of asthma, COPD, idiopathic pulmonary fibrosis, and cystic fibrosis according to the published data. In the second part, we summarize the current evidence concerning the efficacy of the antialarmin therapies in CRD. Recent clinical trials showed that anti-TSLP and IL-33/R antibodies can improve severe asthma outcomes. Blocking the IL-33-mediated pathway decreased the exacerbation rate in COPD patients with more important benefit for former-smokers.

EXPERT OPINION

Despite progress in the understanding of the alarmins' role in the pathogenesis of CRD, all their mechanisms of action are not yet identified. Blocking IL-33 and TSLP pathways offers an interesting option to treat severe asthma and COPD, but future investigations are needed to establish their place in the treatment strategies.

IL-33's role in the gut immune system: A comprehensive review of its crosstalk and regulation

The intestinal tract is the largest immune organ in the human body, comprising a complex network of immune cells and epithelial cells that perform a variety of functions such as nutrient absorption, digestion, and waste excretion. Maintenance of homeostasis and effective responses to injury in the colonic epithelium are crucial for maintaining homeostasis between these two cell types. The onset and perpetuation of gut inflammation, characterizing inflammatory bowel diseases (IBD), are triggered by constitutive dysregulation of cytokine production. IL-33 is a newly characterized cytokine that has emerged as a critical modulator of inflammatory disorders. IL-33 is constitutively expressed in the nuclei of different cell types such as endothelial, epithelial, and fibroblast-like cells. Upon tissue damage or pathogen encounter, IL-33 is released as an alarmin and signals through a heterodimer receptor that consists of serum Stimulation-2 (ST2) and IL-1 receptor accessory protein (IL-1RAcP). IL-33 has the ability to induce Th2 cytokine production and enhance both Th1 and Th2, as well as Th17 immune responses. Exogenous administration of IL-33 in mice caused pathological changes in most mucosal tissues such as the lung and the gastrointestinal (GI) tract associated with increased production of type 2 cytokines and chemokines. In vivo and in vitro, primary studies have exhibited that IL-33 can activate Th2 cells, mast cells, or basophils to produce type 2 cytokines such as IL-4, IL-5, and IL-13. Moreover, several novel cell populations, collectively referred to as "type 2 innate lymphoid cells," were identified as being IL-33 responsive and are thought to be important for initiating type 2 immunity. Nevertheless, the underlying mechanisms by which IL-33 promotes type 2 immunity in the GI tract remain to be fully understood. Recently, it has been discovered that IL-33 plays important roles in regulatory immune responses. Highly suppressive ST2 + FoxP3+ Tregs subsets regulated by IL-33 were identified in several tissues, including lymphoid organs, gut, lung, and adipose tissues. This review aims to comprehensively summarize the current knowledge on IL-33's role in the gut immune system, its crosstalk, and regulation. The article will provide insights into the potential applications of IL-33-based therapies in the treatment of gut inflammatory disorders.

The IL-33/IL-31 Axis in Allergic and Immune-Mediated Diseases

Interleukin 31 (IL-31) belongs to the IL-6 superfamily [...].

The Role of IL-33/ST2 in COPD and Its Future as an Antibody Therapy

COPD is a leading cause of mortality and morbidity worldwide and is associated with a high socioeconomic burden. Current treatment includes the use of inhaled corticosteroids and bronchodilators, which can help to improve symptoms and reduce exacerbations; however, there is no solution for restoring lung function and the emphysema caused by loss of the alveolar tissue. Moreover, exacerbations accelerate progression and challenge even more the management of COPD. Mechanisms of inflammation in COPD have been investigated over the past years, thus opening new avenues to develop novel targeted-directed therapies. Special attention has been paid to IL-33 and its receptor ST2, as they have been found to mediate immune responses and alveolar damage, and their expression is upregulated in COPD patients, which correlates with disease progression. Here we summarize the current knowledge on the IL-33/ST2 pathway and its involvement in COPD, with a special focus on developed antibodies and the ongoing clinical trials using anti-IL-33 and anti-ST2 strategies in COPD patients.

Ferroptosis triggers airway inflammation in asthma

Ferroptosis is a regulatory cell death characterized by intracellular iron accumulation and lipid peroxidation that leads to oxidative stress. Many signaling pathways such as iron metabolism, lipid metabolism, and amino acid metabolism precisely regulate the process of ferroptosis. Ferroptosis is involved in a variety of lung diseases, such as acute lung injury, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Increasing studies suggest that ferroptosis is involved in the development of asthma. Ferroptosis plays an important role in asthma. Iron metabolism disorders, lipid peroxidation, amino acid metabolism disorders lead to the occurrence of ferroptosis in airway epithelial cells, and then aggravate clinical symptoms in asthmatic patients. Moreover, several regulators of ferroptosis are involved in the pathogenesis of asthma, such as Nrf2, heme oxygenase-1, mevalonate pathway, and ferroptosis inhibitor protein 1. Importantly, ferroptosis inhibitors improve asthma. Thus, the pathogenesis of ferroptosis and its contribution to the pathogenesis of asthma help us better understand the occurrence and development of asthma, and provide new directions in asthma treatment. This article aimed to review the role and mechanism of ferroptosis in asthma, describing the relationship between ferroptosis and asthma based on signaling pathways and related regulatory factors. At the same time, we summarized current observations of ferroptosis in eosinophils, airway epithelial cells, and airway smooth muscle cells in asthmatic patients.