TSLP and IL-33 reciprocally promote each other's lung protein expression and ILC2 receptor expression to enhance innate type-2 airway inflammation

Preventing NLRP3 inflammasome activation: Therapeutic atrategy and challenges in atopic dermatitis

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder characterized by its chronic, persistent, and recurrent nature. The pathophysiology of this condition is complex, involving various factors including cell-mediated immune responses, compromised skin barrier function, and alterations in hypersensitivity reactions. These components synergistically contribute to the perpetuation of the bothersome "itch-scratch-itch" cycle. Recent research has highlighted the significant role of the NLRP3 inflammasome in the development of AD and other inflammatory conditions. Current research indicates that the NLRP3 inflammasome plays a pivotal role in both the acute and chronic phases of AD by modulating the Th2/Th1 immune deviation. Moreover, the pharmacological suppression of NLRP3 has shown promising results in mitigating the pathological aspects of AD. This review outlines potential drug development strategies that target the NLRP3 inflammasome as a therapeutic approach for AD and the challenges faced in this endeavor.

Hyperactivity of the IL-33-ILC2s-IL-13-M-MDSCs axis promotes cervical cancer progression

The interleukin-33(IL-33) - group 2 innate lymphoid cells (ILC2s) - interleukin-13(IL-13) - monocytic myeloid-derived suppressor cells (M-MDSCs) axis plays a critical role in promoting immune evasion in tumors; however, its specific function in cervical cancer remains poorly understood. In this study, we observed that the proportion of IL-33-ILC2s-IL-13-M-MDSCs were significantly elevated in both cervical cancer patients and the subcutaneous U14 cervical cancer mouse model, compared to normal controls. Our results suggest that IL-33 stimulates ILC2s to secrete IL-13, which, in turn, regulates M-MDSCs to enhance their immune evasion capabilities. Notably, in vitro blockade of IL-33 and IL-13 partially restored the levels and functions of both ILC2s and M-MDSCs. In conclusion, these findings imply that the overactivation of the IL-33-ILC2s-IL-13-M-MDSCs axis may contribute to cervical cancer progression. However, further in vivo blockade studies are required to fully elucidate the precise mechanisms underlying this interaction and to assess its potential therapeutic implications for cervical cancer.

Group 3 Innate Lymphoid Cells: A Potential Therapeutic Target for Steroid Resistant Asthma

Asthma is a chronic airway inflammatory disease that affects millions globally. Although glucocorticoids are a mainstay of asthma treatment, a subset of patients show resistance to these therapies, resulting in poor disease control and increased morbidity. The complex mechanisms underlying steroid-resistant asthma (SRA) involve Th1 and Th17 lymphocyte activity, neutrophil recruitment, and NLRP3 inflammasome activation. Recent studies provided evidence that innate lymphoid cells type 3 (ILC3s) might be potential therapeutic targets for non-eosinophilic asthma (NEA) and SRA. Like Th17 cells, ILC3s play crucial roles in immune responses, inflammation, and tissue homeostasis, contributing to disease severity and corticosteroid resistance in NEA. Biologics targeting ILC3-related pathways have shown promise in managing Th2-low asthma, suggesting new avenues for SRA treatment. This review aims to explore the risk factors for SRA, discuss the challenges and mechanisms underlying SRA, consolidate current findings on innate lymphoid cells, and elucidate their role in respiratory conditions. We present the latest findings on the involvement of ILC3s in human diseases and explore their potential mechanisms in SRA development. Furthermore, we review emerging therapeutic biologics targeting ILC3-related pathways in managing NEA and SRA. This review highlights current challenges, and emerging therapeutic strategies, and addresses a significant gap in asthma research, with implications for improving the management of steroid-resistant asthma.

IL-33-experienced group 2 innate lymphoid cells in the lung are poised to enhance type 2 inflammation selectively in adult female mice

While Th2 adaptive immunity has long been considered to orchestrate type 2 inflammation in the allergic lung, group 2 innate lymphoid cells (ILC2s), with the ability to produce a similar profile of type 2 cytokines, likely participate in lung inflammation in allergic asthma. ILC2s are also implicated in sex disparities in asthma, supported by data from murine models showing they are inhibited by male sex hormones. Moreover, larger numbers of ILC2s are present in the lungs of female mice and are correlated with greater type 2 inflammation. Lung ILC2s exhibit intriguing memory-like responses, though whether these differ in males and females does not appear to have been addressed. We have examined type 2 lung inflammation in adult male and female Balb/c mice following delivery of IL-33 to the lung. While the number of ILC2s was elevated equally in males and females four weeks after exposure to IL-33, ILC2s from female mice expressed higher levels of ST2, the IL-33 cognate receptor subunit, and a larger proportion of ILC2s from females expressed the IL-25 receptor (IL-25R), which has previously been linked to memory-like ILC2 responses in mice. Our data show that the subset of ILC2s expressing IL-25R, upon activation, was more likely to produce IL-5 and IL-13. Moreover, STAT6 was absolutely required for enhanced responsiveness in this model system. Altogether, our data show that enhanced type 2 inflammation in females is linked to durable changes in ILC2 subsets with the ability to respond more robustly, in a STAT6-dependent manner, upon secondary activation by innate epithelial-derived cytokines.

Endogenous Glucagon-Like Peptide-1 Receptor and Glucose-Dependent Insulinotropic Polypeptide Receptor Signaling Inhibits Aeroallergen-Induced Innate Airway Inflammation

BACKGROUND

Anti-inflammatory effects of incretin signaling through the glucagon-like peptide-1 receptor (GLP-1R) and the glucose-dependent insulinotropic polypeptide receptor (GIPR) in mice have been reported. Therefore, we hypothesized that signaling through the endogenous GLP-1R and the GIPR individually decreases allergic airway inflammation and that the combination of GLP-1R and GIPR signaling together additively inhibits allergen-induced lung and airway inflammation.

METHODS

WT (C57BL/6J), GLP-1R knockout (KO), GIPR KO, and GLP-1R/GIPR double KO (DKO) mice were challenged intranasally with Alternaria alternata extract (Alt-Ext) or vehicle to evaluate the impact of signaling through these receptors on the innate allergen-induced inflammatory response that is primarily driven by group 2 innate lymphoid cells (ILC2).

RESULTS

Alt-Ext-induced IL-33 release in the bronchoalveolar lavage fluid (BALF) was not different between the mouse strains, but thymic stromal lymphopoietin (TSLP) was significantly increased in GLP-1R/GIPR DKO mice challenged with Alt-Ext compared to the other strains. Furthermore, Alt-Ext-induced protein expression of IL-5, IL-13, CCL11, and CCL24 in the lung homogenates, the number of eosinophils, lymphocytes, and neutrophils in the BALF, and the number of lung GATA3+ ILC2 were significantly increased in GLP-1R/GIPR DKO mice compared to the other 3 strains. Furthermore, ICAM-1 expression on lung epithelial cells was increased in GLP-1R/GIPR DKO mice challenged with Alt-Ext compared to the other 3 strains.

CONCLUSIONS

Deficiency of both GLP-1R and GIPR signaling together increased TSLP release, ILC2 activation, and early type 2 innate immune responses to aeroallergen exposure. Combined GLP-1R and GIPR signaling should be explored for the treatment of asthma.

Bisphenol A triggers activation of ocular immune system and aggravates allergic airway inflammation

Bisphenol A (BPA) is widely used in manufacturing plastic products, and it has been reported that exposure through the airway or orally aggravates allergic airway inflammation. Because BPA is detected in the atmosphere and indoor environments, the eyes can also be exposed to BPA. After ocular exposure to BPA and antigen via eye drops, we observed enhanced antigen uptake of antigen-presenting cells (APCs) in tear duct-associated lymphoid tissue (TALT). Additionally, we observed the formation of germinal center (GC) B cells in TALT and induction of allergic airway inflammation in mice sensitized with BPA and antigen via eye drops, followed by airway antigen exposure. We also found that DNAX-activating protein of 12 kDa (DAP12)-deficient mice displayed impaired activation of APCs enhanced by ocular exposure to BPA. These results indicate that ocular sensitization to BPA and allergen triggers allergic inflammation via TALT activation, and that DAP12 might be a key molecule for modulating the ocular immune system.

Elevated circulating group-2 innate lymphoid cells expressing activation markers and correlated tryptase AB1 levels in active ascariasis

Introduction

Ascaris lumbricoides infection is one of the most common soil-transmitted helminthiasis and IgE response to this helminth may increase the risk of asthma, bronchial hyperreactivity and atopy. There is not enough evidence showing the role of group-2 innate lymphoid cells (ILC2) in the pathogenesis of helminth infections in humans. Here, we aimed to investigate and characterize the influence of Ascaris lumbricoides infection on circulating ILCs in endemically exposed subjects.

Methods

Non-infected (NI; n=16) and Ascaris-infected (AI; n=16) subjects from an endemic area were included. Two consecutive stool samples from each subject were examined by Kato-Katz to define parasite infection. Antibodies to the ABA-1 antigen of Ascaris and Ascaris extract were measured by ELISA. ILC subsets and their activation markers (CD25, CD69, thymic stromal lymphopoietin receptor (TSLPR) were evaluated in its PBMC by flow cytometry. Proximity extension assay (PEA) was performed to explore plasma proteins associated to infection.

Results

No significant differences in the relative or absolute frequencies of total ILCs, ILC1, ILC2 and ILC3 cells were observed regarding the infection status. However, within AI group, IgE-sensitized subjects to ABA-1 had higher frequencies and counts of ILC2 (p<0.05). Frequencies of CD25+, CD69+ and TSLPR+ ILC2 were higher in AI compared to the NI (p<0.01). Additionally, egg burden was positively correlated with CD69+ ILC2 frequencies (r=0.67; p=0.005). Tryptase alpha/beta 1 (TPSAB1), GP6 and several plasma proteins associated with cell growth and granulocyte chemotaxis were highly expressed in the AI group (p<0.05). Interestingly, TPSAB1 levels were positively correlated with ILC2 expressing activation markers frequencies, egg burden and IgE levels against Ascaris.

Discussion

Ascaris infection is associated with increased expression of ILC2 activation markers and TPSAB1, which may contribute to the type-2 response.

The role of fibroblast in chronic rhinosinusitis with nasal polyps: a key player in the inflammatory process

INTRODUCTION

Fibroblasts are the primary supporting cells in connective tissue and have long been thought to contribute to chronic rhinosinusitis with nasal polyps (CRSwNP) by producing extracellular matrix (ECM), leading to fibrosis and tissue remodeling. However, recent studies have highlighted the critical role of nasal polyp-derived fibroblasts (NPDFs) in triggering and intensifying the inflammatory response in CRSwNP.

AREAS COVERED

This review undertook a comprehensive literature search across the PubMed database, Web of Science since 2000, offering an in-depth summary of the pivotal role of NPDFs in tissue remodeling and inflammatory responses in CRSwNP. Additionally, single-cell RNA sequencing data provides a deeper exploration of the heterogeneity and functional mechanisms of fibroblasts in CRSwNP. Consequently, these insights point to fibroblasts as promising therapeutic targets for effectively treating CRSwNP.

EXPERT OPINION

Current data underscore the essential role of fibroblasts in the pathogenesis of CRSwNP. Fully elucidating the specific mechanisms by which fibroblasts contribute to the disease process is crucial for developing targeted therapies. Furthermore, advancements in single-cell RNA sequencing pave the way for selectively targeting and depleting pathological fibroblast subpopulations. Despite these advancements, the clinical development of fibroblast-targeted therapies in CRSwNP remains challenging.

Therapeutic relevance of eosinophilic inflammation and airway viral interactions in severe asthma

The role of eosinophils in airway inflammation and asthma pathogenesis is well established, with raised eosinophil counts in blood and sputum associated with increased disease severity and risk of asthma exacerbation. Conversely, there is also preliminary evidence suggesting antiviral properties of eosinophils in the airways. These dual roles for eosinophils are particularly pertinent as respiratory virus infections contribute to asthma exacerbations. Biologic therapies targeting key molecules implicated in eosinophil-associated pathologies have been approved in patients with severe asthma and, therefore, the effects of depleting eosinophils in a clinical setting are of considerable interest. This review discusses the pathological and antiviral roles of eosinophils in asthma and exacerbations. We also highlight the significant reduction in asthma exacerbations seen with biologic therapies, even at the height of the respiratory virus season. Furthermore, we discuss the implications of these findings in relation to the role of eosinophils in inflammation and antiviral responses to respiratory virus infection in asthma.

Human keratinocyte response to 4,4'-methylene diphenyl diisocyanate-glutathione conjugate exposure

Workplace exposure to diisocyanates like 4,4'-methylene diphenyl diisocyanate can cause occupational asthma (MDI-OA), and the underlying biological pathways are still being researched.Although uncertainty remains, evidence supports the hypothesis that dermal exposure to MDI plays an important role in the development of MDI-OA.Gene expression, proteomics, and informatics tools were utilised to characterise changes in expression of RNA and protein in cultured human HEKa keratinocyte cells following exposure to conjugates of MDI with glutathione (MDI-GSH).RT-qPCR analysis using a panel of 39 candidate primers demonstrated 9 candidate genes upregulated and 30 unchanged.HPLC-MS/MS analysis of HEKa cell lysate identified 18 540 proteins across all samples 60 proteins demonstrate statistically significant differential expression in exposed cells, some of which suggest activation of immune and inflammatory pathways.The results support the hypothesis that dermal exposures have the potential to play an important role in the development of MDI-OA. Furthermore, proteomic and gene expression data suggest multiple immune (adaptive and innate) and inflammatory pathways may be involved in the development of MDI-OA.

Pathogenesis, Diagnosis, and Treatment of Infectious Rhinosinusitis

Rhinosinusitis is a common inflammatory disease of the sinonasal mucosa and paranasal sinuses. The pathogenesis of rhinosinusitis involves a variety of factors, including genetics, nasal microbiota status, infection, and environmental influences. Pathogenic microorganisms, including viruses, bacteria, and fungi, have been proven to target the cilia and/or epithelial cells of ciliated airways, which results in the impairment of mucociliary clearance, leading to epithelial cell apoptosis and the loss of epithelial barrier integrity and immune dysregulation, thereby facilitating infection. However, the mechanisms employed by pathogenic microorganisms in rhinosinusitis remain unclear. Therefore, this review describes the types of common pathogenic microorganisms that cause rhinosinusitis, including human rhinovirus, respiratory syncytial virus, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus species, etc. The damage of mucosal cilium clearance and epithelial barrier caused by surface proteins or secreted virulence factors are summarized in detail. In addition, the specific inflammatory response, mainly Type 1 immune responses (Th1) and Type 2 immune responses (Th2), induced by the entry of pathogens into the body is discussed. The conventional treatment of infectious sinusitis and emerging treatment methods including nanotechnology are also discussed in order to improve the current understanding of the types of microorganisms that cause rhinosinusitis and to help effectively select surgical and/or therapeutic interventions for precise and personalized treatment.

Evaluation of bacteriophage ϕ11 host recognition protein and its host-binding peptides for diagnosing/targeting Staphylococcus aureus infections

BACKGROUND

Evaluating the potential of using both synthetic and biological products as targeting agents for the diagnosis, imaging, and treatment of infections due to particularly antibiotic-resistant pathogens is important for controlling infections. This study examined the interaction between Gp45, a receptor-binding protein of the ϕ11 lysogenic phage, and its host Staphylococcus aureus (S. aureus), a common cause of nosocomial infections.

METHODS

Using molecular dynamics and docking simulations, this study identified the peptides that bind to S. aureus wall teichoic acids via Gp45. It compared the binding affinity of Gp45 and the two highest-scoring peptide sequences (P1 and P3) and their scrambled forms using microscopy, spectroscopy, and ELISA.

RESULTS

It was found that rGp45 (recombinant Gp45) and chemically synthesised P1 had a higher binding affinity for S. aureus compared with all other peptides, except for Escherichia coli. Furthermore, rGp45 had a capture efficiency of > 86%; P1 had a capture efficiency of > 64%.

CONCLUSION

These findings suggest that receptor-binding proteins such as rGp45, which provide a critical initiation of the phage life cycle for host adsorption, might play an important role in the diagnosis, imaging, and targeting of bacterial infections. Studying such proteins could accordingly enable the development of effective strategies for controlling infections.

Involvement of Janus kinase-dependent Bcl-xL overexpression in steroid resistance of group 2 innate lymphoid cells in asthma

The mechanisms underlying the development of steroid resistance in asthma remain unclear. To establish whether as well as the mechanisms by which the activation of Janus kinases (JAKs) is involved in the development of steroid resistance in asthma, murine steroid-resistant models of the proliferation of group 2 innate lymphoid cells (ILC2s) in vitro and asthmatic airway inflammation in vivo were analysed. ILC2s in the lungs of BALB/c mice were sorted and then incubated with IL-33, thymic stromal lymphopoietin (TSLP), and/or IL-7 with or without dexamethasone (10 nM), the pan-JAK inhibitor, delgocitinib (1-10 000 nM), and/or the Bcl-xL inhibitor, navitoclax (1-100 nM), followed by the detection of viable and apoptotic cells. The anti-apoptotic factor, Bcl-xL was detected in ILC2s by flow cytometry. As a steroid-resistant asthma model, ovalbumin (OVA)-sensitized BALB/c mice were intratracheally challenged with OVA at a high dose of 500 μg four times. Dexamethasone (1 mg/kg, i.p.), delgocitinib (3-30 mg/kg, p.o.), or navitoclax (30 mg/kg, p.o.) was administered during the challenges. Cellular infiltration into the lungs was analysed by flow cytometry. Airway remodelling was histologically evaluated. The following results were obtained. (1) Cell proliferation concomitant with a decrease in apoptotic cells was induced when ILC2s were cultured with TSLP and/or IL-7, and was potently inhibited by dexamethasone. In contrast, when the culture with TSLP and IL-7 was performed in the presence of IL-33, the proliferative response exhibited steroid resistance. Steroid-resistant ILC2 proliferation was suppressed by delgocitinib in a concentration-dependent manner. (2) The culture with IL-33, TSLP, and IL-7 induced the overexpression of Bcl-xL, which was clearly inhibited by delgocitinib, but not by dexamethasone. When ILC2s were treated with navitoclax, insensitivity to dexamethasone was significantly cancelled. (3) The development of airway remodelling and the infiltration of ILC2s into the lungs in the asthma model were not suppressed by dexamethasone, but were dose-dependently inhibited by delgocitinib. Combination treatment with dexamethasone and either delgocitinib or navitoclax synergistically suppressed these responses. Therefore, JAKs appear to play significant roles in the induction of steroid resistance by up-regulating Bcl-xL in ILC2s. The inhibition of JAKs and Bcl-xL has potential as pharmacotherapy for steroid-resistant asthma, particularly that mediated by ILC2s.

Type 2 severe asthma: pathophysiology and treatment with biologics

INTRODUCTION

The hallmark of most patients with severe asthma is type 2 inflammation, driven by innate and adaptive immune responses leading to either allergic or non-allergic eosinophilic infiltration of airways. The cellular and molecular pathways underlying severe type 2 asthma can be successfully targeted by specific monoclonal antibodies.

AREAS COVERED

This review article provides a concise overview of the pathophysiology of type 2 asthma, followed by an updated appraisal of the mechanisms of action and therapeutic efficacy of currently available biologic treatments used for management of severe type 2 asthma. Therefore, all reported information arises from a wide literature search performed on PubMed.

EXPERT OPINION

The main result of the recent advances in the field of anti-asthma biologic therapies is the implementation of a personalized medicine approach, aimed to achieve clinical remission of severe asthma. Today this accomplishment is made possible by the right choice of the most beneficial biologic drug for the pathologic traits characterizing each patient, including type 2 severe asthma and its comorbidities.

Upper Airway Alarmin Cytokine Expression in Asthma of Different Severities

Background: The secretion of alarmin cytokines by epithelial cells, including thymic stromal lymphopoietin (TSLP), interleukin (IL)-25, and IL-33, initiates inflammatory cascades in asthma. However, alarmin cytokine expression in the upper airways in asthma remains largely unknown. Methods: We recruited 40 participants with asthma into four groups as per the Global Initiative for Asthma (GINA) steps (10 in each group of GINA 1/2, 3, 4, and 5). Cells were derived from nasal, buccal, and throat brushings. Intracellular cytokine expression (TSLP, IL-25, and IL-33) was assessed by flow cytometry in cytokeratin 8+ (Ck8+) epithelial cells immediately following collection. Results: TSLP was significantly increased (p < 0.001) in GINA 5 patients across nasal, buccal, and throat Ck8+ epithelial cells, while IL-25 was elevated in nasal and throat samples (p < 0.003), and IL-33 levels were variable, compared with GINA 1-4 patients. Individual GINA subgroup comparison showed that TSLP levels in nasal samples from GINA 5 patients were significantly (p = 0.03) elevated but did not differ between patients with and without nasal comorbidities. IL-25 and IL-33 (obtained from nasal, buccal, and throat samples) were not significantly different in individual groups. Conclusions: Our study demonstrates for the first time that Ck8+ nasal epithelial cells from GINA 5 asthma patients express elevated levels of TSLP.

Alternaria Allergy and Immunotherapy

BACKGROUND

Allergen immunotherapy (AIT) is the only known causative treatment for Alternaria allergy, but the difficulty in standardizing Alternaria extracts hampers its effectiveness and safety.

SUMMARY

Alternaria, a potent airborne allergen, has a high sensitization rate and is known to trigger the onset and exacerbation of respiratory allergies, even inducing fungal food allergy syndrome in some cases. It can trigger a type 2 inflammatory response, leading to an increase in the secretion of type 2 inflammatory cytokines and eosinophils, which are the culprits behind allergic symptoms. Diagnosing Alternaria allergy is a multistep process, involving a careful examination of clinical symptoms, medical history, skin prick tests, serum-specific IgE detection, or provocation tests. Alt a1, the major component of Alternaria, is a vital player in diagnosing Alternaria allergy through component-resolved diagnosis. Interestingly, Alternaria can reduce the protein activity of other allergens like pollen and cat dander when mixed with them. In order to solve the problems of standardization, efficacy and safety of traditional Alternaria AIT, novel AIT methods targeting Alt a1 and innovative vaccines such as epitope, DNA, and mRNA vaccines seem promising in bypassing the standardization issue of Alternaria extracts. But these studies are in early stages, and most researches are still focused on animal models, calling for more evidence to validate their use in humans.

KEY MESSAGES

This review delves into the various aspects of Alternaria allergy, including characteristics, epidemiology, immune mechanisms, diagnosis, clinical manifestations, and the application and limitations of Alternaria AIT, aiming to provide a foundation for the management of patients with Alternaria allergy.

Tacrolimus alleviates pulmonary fibrosis progression through inhibiting the activation and interaction of ILC2 and monocytes

Idiopathic pulmonary fibrosis (IPF) is a heterogeneous group of lung diseases with different etiologies and characterized by progressive fibrosis. This disease usually causes pulmonary structural remodeling and decreased pulmonary function. The median survival of IPF patients is 2-5 years. Predominantly accumulation of type II innate immune cells accelerates fibrosis progression by secreting multiple pro-fibrotic cytokines. Group 2 innate lymphoid cells (ILC2) and monocytes/macrophages play key roles in innate immunity and aggravate the formation of pro-fibrotic environment. As a potent immunosuppressant, tacrolimus has shown efficacy in alleviating the progression of pulmonary fibrosis. In this study, we found that tacrolimus is capable of suppressing ILC2 activation, monocyte differentiation and the interaction of these two cells. This effect further reduced activation of monocyte-derived macrophages (Mo-M), thus resulting in a decline of myofibroblast activation and collagen deposition. The combination of tacrolimus and nintedanib was more effective than either drug alone. This study will reveal the specific process of tacrolimus alleviating pulmonary fibrosis by regulating type II immunity, and explore the potential feasibility of tacrolimus combined with nintedanib in the treatment of pulmonary fibrosis. This project will provide new ideas for clinical optimization of anti-pulmonary fibrosis drug strategies.

Exploring TSLP and IL-33 Serum Levels and Genetic Variants: Unveiling Their Limited Potential as Biomarkers for Mild Asthma in Children

As the burden of mild asthma is not well understood, the significance of expanding research in the group of patients with mild asthma is emphasized. Thymic stromal lymphopoietin (TSLP) and interleukin 33 (IL-33) are involved in the pathogenesis of atopy and the immune response to inhaled environmental insults, such as allergens, in asthmatic patients. Objectives: The objective of this study was to explore the correlation between specific polymorphisms within the genes encoding TSLP and IL-33, as well as the concentrations of TSLP and IL-33 in the serum, and the occurrence of pediatric mild asthma. Methods: The analysis encompassed 52 pediatric patients diagnosed with mild bronchial asthma, including both atopic and non-atopic cases, and a control group of 26 non-asthmatic children. Recruitment was conducted through a comprehensive questionnaire. Parameters such as allergic sensitization, serum levels of circulating TSLP and IL-33, and the identification of single-nucleotide polymorphisms in TSLP (rs11466750 and rs2289277) and IL-33 (rs992969 and rs1888909) were assessed for all participants. Results: Significantly lower mean serum TSLP concentrations were observed in asthmatic subjects compared to the control group, with atopic asthma patients showing even lower TSLP levels than non-atopic counterparts. No significant differences were found in mean serum IL-33 concentrations between the two groups. Considering the allele model, for both tested SNPs of IL-33, we observed that patients with asthma, atopic asthma, and atopy statistically less frequently possess the risk allele. Conclusions: Our study findings suggest that IL-33 and TSLP do not serve as ideal biomarkers for mild asthma in children. Their effectiveness as biomarkers might be more relevant for assessing disease severity rather than identifying asthma in pediatric patients. Further research focusing on the association between TSLP and IL-33 gene polymorphisms and asthma is expected to significantly advance disease management.

Advances in co-pathogenesis of the united airway diseases

According to the concept of "united airway diseases", the airway is a single organ in which upper and lower airway diseases are commonly comorbid. A range of inflammatory factors have been found to play an important role in the chain reaction of upper and lower airway diseases. However, the amount of research on this concept remains limited. The underlying mechanism of the relationship between typical diseases of the united airway, such as asthma, allergic rhinitis, and chronic sinusitis, also needs to be further explored. This review highlights the interaction between upper and lower respiratory diseases gathered from epidemiological, histoembryology, neural mechanistic, microbiological, and clinical studies, revealing the relationship between the upper and lower respiratory tracts.

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.

Recruitment of PVT1 Enhances YTHDC1-Mediated m6A Modification of IL-33 in Hyperoxia-Induced Lung Injury During Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that specifically affects preterm infants. Oxygen therapy administered to treat BPD can lead to hyperoxia-induced lung injury, characterized by apoptosis of lung alveolar epithelial cells. Our epitranscriptomic microarray analysis of normal mice lungs and hyperoxia-stimulated mice lungs revealed elevated RNA expression levels of IL-33, as well as increased m6A RNA methylation levels of IL-33 and PVT1 in the hyperoxia-stimulated lungs. This study aimed to investigate the role of the PVT1/IL-33 axis in BPD. A mouse model of BPD was established through hyperoxia induction, and lung histological changes were assessed by hematoxylin-eosin staining. Parameters such as radial alveolar count and mean chord length were measured to assess lung function. Mouse and human lung alveolar epithelial cells (MLE12 and A549, respectively) were stimulated with hyperoxia to create an in vitro BPD model. Cell apoptosis was detected using Western blotting and flow cytometry analysis. Our results demonstrated that silencing PVT1 suppressed apoptosis in MLE12 and A549 cells and improved lung function in hyperoxia-stimulated lungs. Additionally, IL-33 reversed the effects of PVT1 both in vivo and in vitro. Through online bioinformatics analysis and RNA-binding protein immunoprecipitation assays, YTHDC1 was identified as a RNA-binding protein (RBP) for both PVT1 and IL-33. We found that PVT1 positively regulated IL-33 expression by recruiting YTHDC1 to mediate m6A modification of IL-33. In conclusion, silencing PVT1 demonstrated beneficial effects in alleviating BPD by facilitating YTHDC1-mediated m6A modification of IL-33. Inhibition of the PVT1/IL-33 axis to suppress apoptosis in lung alveolar epithelial cells may hold promise as a therapeutic approach for managing hyperoxia-induced lung injury in BPD.

Promyelocytic leukemia zinc finger controls type 2 immune responses in the lungs by regulating lineage commitment and the function of innate and adaptive immune cells

Type 2 immune responses are critical for host defense, mediate allergy and Th2-high asthma. The transcription factor, promyelocytic leukemia zinc finger (PLZF), has emerged as a significant regulator of type 2 inflammation in the lung; however, its exact mechanism remains unclear. In this review, we summarized recent findings regarding the ability of PLZF to control the development and function of innate lymphoid cells (ILCs), iNKT cells, memory T cells, basophils, and other immune cells that drive type 2 responses. We discussed the important role of PLZF in the pathogenesis of Th2-high asthma. Collectively, prior studies have revealed the critical role of PLZF in the regulation of innate and adaptive immune cells involved in type 2 inflammation in the lung. Therefore, targeting PLZF signaling represents a promising therapeutic approach to suppress Th2-high asthma.

UHPLC/MS-based metabolomics of asthmatic mice reveals metabolic changes in group 2 innate lymphoid cells

Helper Th2-type immune responses are essential in allergic airway diseases, including asthma and allergic rhinitis. Recent studies have indicated that group 2 innate lymphoid cells (ILC2s) play a crucial role in the occurrence and development of asthma. However, the metabolic profile of ILC2s and their regulatory mechanisms in asthma remain unclear. Therefore, we established two asthma mouse models: an ovalbumin (OVA)-induced asthma model and an IL-33-induced asthma model. We then used ultra-high-performance liquid chromatography/mass spectrometry (UHPLC/MS) to conduct high-throughput untargeted metabolic analysis of ILC2s in the lung tissues of the asthma models. The identified metabolites primarily consisted of lipids, lipid-like molecules, benzene, organic acids, derivatives, and organic oxidation compounds. Specifically, 34 differentially accumulated metabolites influenced the metabolic profiles of the control and OVA-induced asthma model groups. Moreover, the accumulation of 39 metabolites significantly differed between the Interleukin 33 (IL-33) and control groups. These differentially accumulated metabolites were mainly involved in pathways such as sphingolipid, oxidative phosphorylation, and fatty acid metabolism. This metabolomic study revealed, for the first time, the key metabolites and metabolic pathways of ILC2s, revealing new aspects of cellular metabolism in the context of airway inflammation. These findings not only contribute to unraveling the pathogenesis of asthma but also provide a crucial theoretical foundation for the future development of therapeutic strategies targeting ILC2s.

Multifactorial Causes and Consequences of TLSP Production, Function, and Release in the Asthmatic Airway

Disruption of the airway epithelium triggers a defensive immune response that begins with the production and release of alarmin cytokines. These epithelial-derived alarmin cytokines, including thymic stromal lymphopoietin (TSLP), are produced in response to aeroallergens, viruses, and toxic inhalants. An alarmin response disproportionate to the inhaled trigger can exacerbate airway diseases such as asthma. Allergens inhaled into previously sensitized airways are known to drive a T2 inflammatory response through the polarization of T cells by dendritic cells mediated by TSLP. Harmful compounds found within air pollution, microbes, and viruses are also triggers causing airway epithelial cell release of TSLP in asthmatic airways. The release of TSLP leads to the development of inflammation which, when unchecked, can result in asthma exacerbations. Genetic and inheritable factors can contribute to the variable expression of TSLP and the risk and severity of asthma. This paper will review the various triggers and consequences of TSLP release in asthmatic airways.

Edaravone alleviated allergic airway inflammation by inhibiting oxidative stress and endoplasmic reticulum stress

Oxidative stress and endoplasmic reticulum stress (ERS) was associated with the development of asthma. Edaravone (EDA) plays a classical role to prevent the occurrence and development of oxidative stress-related diseases. Herein, we investigated the involvement and signaling pathway of EDA in asthma, with particular emphasis on its impact on type 2 innate lymphoid cells (ILC2) and CD4+T cells, and then further elucidated whether EDA could inhibit house dust mite (HDM)-induced allergic asthma by affecting oxidative stress and ERS. Mice received intraperitoneally injection of EDA (10 mg/kg, 30 mg/kg), dexamethasone (DEX) and N-acetylcysteine (NAC), with the latter two used as positive control drugs. DEX and high dose of EDA showed better therapeutic effects in alleviating airway inflammation and mucus secretion in mice, along with decreasing eosinophils and neutrophils in bronchoalveolar lavage fluid (BALF) than NAC. Further, the protein levels of IL-33 in lung tissues were inhibited by EDA, leading to reduced activation of ILC2s in the lung. EDA treatment alleviated the activation of CD4+ T cells in lung tissues of HDM-induced asthmatic mice and reduced Th2 cytokine secretion in BALF. ERS-related markers (p-eIF2α, IRE1α, CHOP, GRP78) were decreased after treatment of EDA compared to HDM group. Malondialdehyde (MDA), glutathione (GSH), hydrogen peroxide (H2O2), and superoxide dismutase (SOD) were detected to evaluate the oxidant stress in lung tissues. EDA showed a protective effect against oxidant stress. In conclusion, our findings demonstrated that EDA could suppress allergic airway inflammation by inhibiting oxidative stress and ERS, suggesting to serve as an adjunct medication for asthma in the future.

Tezepelumab decreases airway epithelial IL-33 and T2-inflammation in response to viral stimulation in patients with asthma

BACKGROUND

Respiratory virus infections are main triggers of asthma exacerbations. Tezepelumab, an anti-TSLP mAb, reduces exacerbations in patients with asthma, but the effect of blocking TSLP on host epithelial resistance and tolerance to virus infection is not known.

AIM

To examine effects of blocking TSLP in patients with asthma on host resistance (IFNβ, IFNλ, and viral load) and on the airway epithelial inflammatory response to viral challenge.

METHODS

Bronchoalveolar lavage fluid (BALF, n = 39) and bronchial epithelial cells (BECs) were obtained from patients with uncontrolled asthma before and after 12 weeks of tezepelumab treatment (n = 13) or placebo (n = 13). BECs were cultured in vitro and exposed to the viral infection mimic poly(I:C) or infected by rhinovirus (RV). Alarmins, T2- and pro-inflammatory cytokines, IFNβ IFNλ, and viral load were analyzed by RT-qPCR and multiplex ELISA before and after stimulation.

RESULTS

IL-33 expression in unstimulated BECs and IL-33 protein levels in BALF were reduced after 12 weeks of tezepelumab. Further, IL-33 gene and protein levels decreased in BECs challenged with poly(I:C) after tezepelumab whereas TSLP gene expression remained unaffected. Poly(I:C)-induced IL-4, IL-13, and IL-17A release from BECs was also reduced with tezepelumab whereas IFNβ and IFNλ expression and viral load were unchanged.

CONCLUSION

Blocking TSLP with tezepelumab in vivo in asthma reduced the airway epithelial inflammatory response including IL-33 and T2 cytokines to viral challenge without affecting anti-viral host resistance. Our results suggest that blocking TSLP stabilizes the bronchial epithelial immune response to respiratory viruses.

Early-life pulmonary viral infection leads to long-term functional and lower airway structural changes in the lungs

Early-life respiratory virus infections have been correlated with enhanced development of childhood asthma. In particular, significant numbers of respiratory syncytial virus (RSV)-hospitalized infants go on to develop lung disease. It has been suggested that early-life viral infections may lead to altered lung development or repair that negatively impacts lung function later in life. Our data demonstrate that early-life RSV infection modifies lung structure, leading to decreased lung function. At 5 wk postneonatal RSV infection, significant defects are observed in baseline pulmonary function test (PFT) parameters consistent with decreased lung function as well as enlarged alveolar spaces. Lung function changes in the early-life RSV-infected group continue at 3 mo of age. The altered PFT and structural changes induced by early-life RSV were mitigated in TSLPR-/- mice that have previously been shown to have reduced immune cell accumulation associated with a persistent Th2 environment. Importantly, long-term effects were demonstrated using a secondary RSV infection 3 mo following the initial early-life RSV infection and led to significant additional defects in lung function, with severe mucus deposition within the airways, and consolidation of the alveolar spaces. These studies suggest that early-life respiratory viral infection leads to alterations in lung structure/repair that predispose to diminished lung function later in life.NEW & NOTEWORTHY These studies outline a novel finding that early-life respiratory virus infection can alter lung structure and function long-term. Importantly, the data also indicate that there are critical links between inflammatory responses and subsequent events that produce a more severe pathogenic response later in life. The findings provide additional data to support that early-life infections during lung development can alter the trajectory of airway function.

Identification of Hit Compounds Using Artificial Intelligence for the Management of Allergic Diseases

This study aimed to identify and evaluate drug candidates targeting the kinase inhibitory region of suppressor of cytokine signaling (SOCS) 3 for the treatment of allergic rhinitis (AR). Utilizing an artificial intelligence (AI)-based new drug development platform, virtual screening was conducted to identify compounds inhibiting the SH2 domain binding of SOCS3. Luminescence assays assessed the ability of these compounds to restore JAK-2 activity diminished by SOCS3. Jurkat T and BEAS-2B cells were utilized to investigate changes in SOCS3 and STAT3 expression, along with STAT3 phosphorylation in response to the identified compounds. In an OVA-induced allergic rhinitis mouse model, we measured serum levels of total IgE and OVA-specific IgE, performed real-time PCR on nasal mucosa samples to quantify Th2 cytokines and IFN-γ expression, and conducted immunohistochemistry to analyze eosinophil levels. Screening identified 20 hit compounds with robust binding affinities. As the concentration of SOCS3 increased, a corresponding decrease in JAK2 activity was observed. Compounds 5 and 8 exhibited significant efficacy in restoring JAK2 activity without toxicity. Treatment with these compounds resulted in reduced SOCS3 expression and the reinstatement of STAT3 phosphorylation in Jurkat T and BEAS-2B cells. In the OVA-induced allergic rhinitis mouse model, compounds 5 and 8 effectively alleviated nasal symptoms and demonstrated lower levels of immune markers compared to the allergy group. This study underscores the promising nonclinical efficacy of compounds identified through the AI-based drug development platform. These findings introduce innovative strategies for the treatment of AR and highlight the potential therapeutic value of targeting SOCS3 in managing AR.

Bovine Serum Albumin Elicits IL-33-Dependent Adipose Tissue Eosinophilia: Potential Relevance to Ovalbumin-induced Models of Allergic Disease

All cells of the immune system reside in adipose tissue (AT), and increasing type 2 immune cells may be a therapeutic strategy to improve metabolic health. In our previous study using i.p. IL-5 injections to increase eosinophils, we observed that a standard vehicle control of 0.1% BSA also elicited profound AT eosinophilia. In this study, we aimed to determine whether BSA-induced AT eosinophilia results in metabolic benefits in murine models of diet-induced obesity. I.p. 0.1% BSA injections increased AT eosinophils after 4 wk. Despite elevating eosinophils to >50% of immune cells in the AT, body weight and glucose tolerance were not different between groups. Interestingly, BSA elicited epithelial IL-33 production, as well as gene expression for type 2 cytokines and IgE production that were dependent on IL-33. Moreover, multiple models of OVA sensitization also drove AT eosinophilia. Following transplantation of a donor fat pad with BSA-induced eosinophilia, OVA-sensitized recipient mice had higher numbers of bronchoalveolar lavage eosinophils that were recipient derived. Interestingly, lungs of recipient mice contained eosinophils, macrophages, and CD8 T cells from the donor AT. These trafficked similarly from BSA- and non-BSA-treated AT, suggesting even otherwise healthy AT serves as a reservoir of immune cells capable of migrating to the lungs. In conclusion, our studies suggest that i.p. injections of BSA and OVA induce an allergic response in the AT that elicits eosinophil recruitment, which may be an important consideration for those using OVA in animal models of allergic disease.

Neferine Attenuates HDM-Induced Allergic Inflammation by Inhibiting the Activation of Dendritic Cell

House dust mite (HDM) acts as an environmental antigen that might cause chronic allergic diseases. Neferine (NEF) shows anti-inflammation therapeutic effects. This study is to explore the protection role of NEF against HDM-induced allergic inflammation. HDM-induced allergic asthmatic C57BL/6J mice models were established. Differential histological staining was used to analyze lung tissue pathological scores. Flow cytometry was used to analyze subtypes and biomarker expression of immune cells. RT-PCR and ELISA were used to test cytokines-related gene and/or protein expression levels. Western blot was performed to investigate the signaling pathway that mediates allergic inflammation from mice lung tissue and bone marrow-derived dendritic cells (BMDCs). H&E and PAS staining results indicate NEF significantly attenuated inflammatory index and the percentage of goblet cells in the lung tissue induced by HDM. The HDM-elevated TH2 and TH17 cells were significantly decreased by NEF; inflammatory cytokines Il-4, Il-13 and Il-17 were dramatically downregulated in the NEF plus HDM group compared with HDM alone. CD40+ and CD86+ DCs, eosinophils and mast cells, and ILC2 cells were decreased by NEF which was elevated under HDM stimulation. In vivo and ex vivo investigations indicated NEF can attenuate the activated NF-κB signaling induced by HDM is involved in allergic inflammatory immune response and regulates cytokines-related gene expression. HDM-activated DCs promoted differentiation of TH2 and TH17 cells but were attenuated by NEF. This study suggests NEF interrupts the overexpression of some cytokines released by DCs, TH2, and TH17 cells; NEF attenuates HDM-induced allergic inflammation via inhibiting NF-κB signaling of DCs.

The evaluation of biotechnological potential of Gp144, the key molecule of natural predator bacteriophage K in Staphylococcus aureus hunting mechanism

Bacteriophages, which selectively infect bacteria, and phage-derived structures are considered promising agents for the diagnosis and treatment of bacterial infections due to the increasing antibiotic resistance. The binding of phages to their specific receptors on host bacteria is highly specific and irreversible, and therefore, the characterization of receptor-binding proteins(RBPs), which are key determinants of phage specificity, is crucial for the development of new diagnostic and therapeutic products. This study highlights the biotechnological potential of Gp144, an RBP located in the tail baseplate of bacteriophage K and responsible for adsorption of phageK to S. aureus. Once it was established that recombinant Gp144 (rGp144)is biocompatible and does not exhibit lytic effects on bacteria, its interaction with the host, the binding efficiency and performance were assessed in vitro using microscopic and serological methods. Results showed that rGp144 has a capture efficiency (CE) of over 87% and the best CE score is %96 which captured 9 CFU mL-1 out of 10 CFU mL-1 bacteria, indicating that very low number of bacteria could be detected. Additionally, it was shown for the first time in the literature that rGp144 binds to both S. aureus and methicillin-resistant S. aureus (MRSA) cells in vitro, while its affinity to different Gram-positive bacteria (E. faecalis and B. cereus) was not observed. The findings suggest that rGp144 can be effectively used for the diagnosis of S. aureus and MRSA, and that the use of RBPs in host-phage interaction can be a novel and effective strategy for imaging and diagnosing the site of infection.

RORα overexpression reduced interleukin-33 expression and prevented mast cell degranulation and inflammation by inducing autophagy in allergic rhinitis

BACKGROUND

Retinoid acid receptor related orphan receptor α (RORα) is a nuclear receptor that along with other bioactive factors regulates cell proliferation, differentiation, and immunomodulation in vivo.

AIMS

The objective of this study was to explore the function and mechanism of RORα in allergic rhinitis (AR).

MATERIALS AND METHODS

Derp1 was used to construct an AR cell model in HNEpC cells, and RORα was overexpressed or silenced in the AR HNEpC cells. Next, LAD2 cells were co-cultured with the Derp1-treated HNEpC cells. Additionally, an AR mouse model was established using by OVA, and a RORα Adenovirus was delivered by nebulizing. Pathological tissue structures were evaluated by hematoxylin-eosin staining, and the levels of RORα, interleukin-33 (IL-33), and other proteins were analyzed immunohistochemistry, western blotting, and immunofluorescence staining. IL-33, IL-4, IL-5, and IL-13 levels were detected using enzyme-linked immunosorbent assay kits and cell migration was assessed by Transwell assays.

RESULTS

Our data showed that RORα was downregulated in the nasal mucosa tissues of AR patients. Derp1 treatment could cause a downregulation of RORα, upregulation of IL-33, the induction of NLRP3 inflammasomes, and cell migration in HNEpC cells. Furthermore, RORα overexpression dramatically attenuated IL-33 levels, NLRP3 inflammasome activity, and the migration of AR HNEpC cells induced with Derp1. Moreover, RORα in AR HNEpC cells could prevent mast cell (MC) degranulation and inflammation by accelerating autophagy, RORα overexpression inhibited MC degranulation and NLRP3-induced inflammation in the AR model mice. RORα overexpression reduced IL-33 expression in nasal epithelial cells, and also suppressed MC degranulation and inflammation by promoting autophagy.

CONCLUSION

RORα inhibits NLRP3 inflammasome in HNEpC, and attenuated mast cells degranulation and inflammation through autophagy in AR.

Serum biomarkers of remodeling in severe asthma with fixed airway obstruction and the potential role of KL-6

Over 3% of asthmatic patients are affected by a particularly severe form of the disease ("severe asthma", SA) which is often refractory to standard treatment. Airway remodeling (AR), which can be considered a critical characteristic of approximately half of all patients with SA and currently thought to be the main mechanism triggering fixed airway obstruction (FAO), seems to be a key factor affecting a patient's outcome. Despite the collective efforts of internationally renowned experts, to date only a few biomarkers indicative of AR and no recognizable biomarkers of lung parenchymal remodeling have been identified. This work examines the pathogenesis of airway and lung parenchymal remodeling and the serum biomarkers that may be able to identify the severe asthmatic patients who may develop FAO. The study also aims to examine if Krebs von den Lungen-6 (KL-6) could be considered a diagnostic biomarker of lung structural damage in SA.

Type 2 innate lymphoid cell-derived amphiregulin regulates type II alveolar epithelial cell transdifferentiation in a mouse model of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants characterized by alveolar growth arrest. Interleukin (IL)-33 and type 2 innate lymphoid cell (ILC2) affect type II alveolar epithelial cell (AECII) differentiation in BPD mice and may cause increased lung epithelial-mesenchymal transition (EMT). Amphiregulin (AREG) can be produced by ILC2 and is associated with tissue repair. However, the action mechanism of AREG produced by ILC2 to alveolar development in BPD is unclear. In this study, we aimed to demonstrate the role and mechanism of AREG in influencing AECII transdifferentiation in the lung tissue of BPD mice. The effects of ILC2-derived AREG on AECII transdifferentiation were verified in vivo and in vitro, and the role of IL-33 on ILC2-derived AREG in AECII transdifferentiation in BPD mice and a preliminary investigation of the role of AREG's receptor-epidermal growth factor receptor (EGFR) on AECII transdifferentiation. The results showed that neonatal mice developed severe lung injury after hyperoxia, and IL-33 induced AREG production via ILC2 affected normal AECII differentiation and promoted EMT. In addition, the blockade of EGFR was found to alleviate the impaired AECII differentiation under hyperoxia in an in vitro study. In summary, our study demonstrates that AREG secreted by ILC2 affects AECII transdifferentiation in BPD mice, which provides a new idea for the clinical treatment of BPD.

Novel mechanistic insights underlying fungal allergic inflammation

The worldwide prevalence of asthma and allergic disorders (allergic rhinitis, atopic dermatitis, food allergy) has been steadily rising in recent decades. It is now estimated that up to 20% of the global population is afflicted by an allergic disease, with increasing incidence rates in both high- and low-income countries. The World Allergy Organization estimates that the total economic burden of asthma and allergic rhinitis alone is approximately $21 billion per year. While allergic stimuli are a complex and heterogenous class of inputs including parasites, pollens, food antigens, drugs, and metals, it has become clear that fungi are major drivers of allergic disease, with estimates that fungal sensitization occurs in 20-30% of atopic individuals and up to 80% of asthma patients. Fungi are eukaryotic microorganisms that can be found throughout the world in high abundance in both indoor and outdoor environments. Understanding how and why fungi act as triggers of allergic type 2 inflammation will be crucial for combating this important health problem. In recent years, there have been significant advances in our understanding of fungi-induced type 2 immunity, however there is still much we don't understand, including why fungi have a tendency to induce allergic reactions in the first place. Here, we will discuss how fungi trigger type 2 immune responses and posit why this response has been evolutionarily selected for induction during fungal encounter.

Type 2 chronic inflammatory diseases: targets, therapies and unmet needs

Over the past two decades, significant progress in understanding of the pathogenesis of type 2 chronic inflammatory diseases has enabled the identification of compounds for more than 20 novel targets, which are approved or at various stages of development, finally facilitating a more targeted approach for the treatment of these disorders. Most of these newly identified pathogenic drivers of type 2 inflammation and their corresponding treatments are related to mast cells, eosinophils, T cells, B cells, epithelial cells and sensory nerves. Epithelial barrier defects and dysbiotic microbiomes represent exciting future drug targets for chronic type 2 inflammatory conditions. Here, we review common targets, current treatments and emerging therapies for the treatment of five major type 2 chronic inflammatory diseases - atopic dermatitis, chronic prurigo, chronic urticaria, asthma and chronic rhinosinusitis with nasal polyps - with a high need for targeted therapies. Unmet needs and future directions in the field are discussed.

Advancing Treatment Strategies: A Comprehensive Review of Drug Delivery Innovations for Chronic Inflammatory Respiratory Diseases

Chronic inflammatory respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, present ongoing challenges in terms of effective treatment and management. These diseases are characterized by persistent inflammation in the airways, leading to structural changes and compromised lung function. There are several treatments available for them, such as bronchodilators, immunomodulators, and oxygen therapy. However, there are still some shortcomings in the effectiveness and side effects of drugs. To achieve optimal therapeutic outcomes while minimizing systemic side effects, targeted therapies and precise drug delivery systems are crucial to the management of these diseases. This comprehensive review focuses on the role of drug delivery systems in chronic inflammatory respiratory diseases, particularly nanoparticle-based drug delivery systems, inhaled corticosteroids (ICSs), novel biologicals, gene therapy, and personalized medicine. By examining the latest advancements and strategies in these areas, we aim to provide a thorough understanding of the current landscape and future prospects for improving treatment outcomes in these challenging conditions.

Interferons as negative regulators of ILC2s in allergic lung inflammation and respiratory viral infections

Group 2 innate lymphoid cells (ILC2s), characterized by a lack of antigen receptors, have been regarded as an important component of type 2 pulmonary immunity. Analogous to Th2 cells, ILC2s are capable of releasing type 2 cytokines and amphiregulin, thus playing an essential role in a variety of diseases, such as allergic diseases and virus-induced respiratory diseases. Interferons (IFNs), an important family of cytokines with potent antiviral effects, can be triggered by microbial products, microbial exposure, and pathogen infections. Interestingly, the past few years have witnessed encouraging progress in revealing the important role of IFNs and IFN-producing cells in modulating ILC2 responses in allergic lung inflammation and respiratory viral infections. This review underscores recent progress in understanding the role of IFNs and IFN-producing cells in shaping ILC2 responses and discusses disease phenotypes, mechanisms, and therapeutic targets in the context of allergic lung inflammation and infections with viruses, including influenza virus, rhinovirus (RV), respiratory syncytial virus (RSV), and severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2).

NFκB1 inhibits memory formation and supports effector function of ILC2s in memory-driven asthma

Background

ILC2s are capable of generating memory. The mechanism of memory induction and memory-driven effector function (trained immunity) in ILC2s is unknown.

Objective

NFκB1 is preferentially expressed at a high level in ILC2s. We examined the role of NFkB1 in memory induction and memory-driven effector function in a mouse model of asthma.

Methods

Intranasal administration of Alternaria, flexivent, ELISA, histology, real-time PCR, western blot, flow cytometry and immunofluorescence staining.

Results

NFκB1 was essential for the effector phase of memory-driven asthma. NFκB1 was critical for IL33 production, ILC2 generation, and production of type-2 cytokines, which resulted in eosinophilic inflammation and other features of asthma. NFκB1 induction of type-2 cytokines in ILC2s was independent of GATA3. NFκB1 was important for allergen induction of ILC3s and FoxP3+ Tregs. NFκB1 did not affect Th2 cells or their cytokine production. In contrast to its protagonistic role in the effector phase, NFκB1 had an antagonistic role in the memory phase. NFκB1 inhibited allergen-induced upregulation of memory-associated repressor and preparedness genes in ILC2s. NFκB1 upregulated RUNX1. NFκB1 formed a heterodimer with RUNX1 in ILC2s.

Conclusions

NFκB1 positively regulated the effector phase but inhibited the induction phase of memory. The foregoing pointed to an interdependent antagonism between the memory induction and the memory effector processes. The NFκB1-RUNX1 heterodimer represented a non-canonical transcriptional activator of type-2 cytokines in ILC2s.

Extended characterization of IL-33/ST2 as a predictor for wound age determination in skin wound tissue samples of humans and mice

Interleukin (IL)-33, an important inflammatory cytokine, is highly expressed in skin wound tissue and serum of humans and mice, and plays an essential role in the process of skin wound healing (SWH) dependent on the IL-33/suppression of tumorigenicity 2 (ST2) pathway. However, whether IL-33 and ST2 themselves, as well as their interaction, can be applied for skin wound age determination in forensic practice remains incompletely characterized. Human skin samples with injured intervals of a few minutes to 24 hours (hs) and mouse skin samples with injured intervals of 1 h to 14 days (ds) were collected. Herein, the results demonstrated that IL-33 and ST2 are increased in the human skin wounds, and that in mice skin wounds, there is an increase over time, with IL-33 expression peaking at 24 hs and 10 ds, and ST2 expression peaking at 12 hs and 7 ds. Notably, the relative quantity of IL-33 and ST2 proteins < 0.35 suggested a wound age of 3 hs; their relative quantity > 1.0 suggested a wound age of 24 hs post-mouse skin wounds. In addition, immunofluorescent staining results showed that IL-33 and ST2 were consistently expressed in the cytoplasm of F4/80-positive macrophages and CD31-positive vascular endothelial cells with or without skin wounds, whereas nuclear localization of IL-33 was absent in α-SMA-positive myofibroblasts with skin wounds. Interestingly, IL-33 administration facilitated the wound area closure by increasing the proliferation of cytokeratin (K) 14 -positive keratinocytes and vimentin-positive fibroblasts. In contrast, treating with its antagonist (i.e., anti-IL-33) or receptor antagonist (e.g., anti-ST2) exacerbated the aforementioned pathological changes. Moreover, treatment with IL-33 combined with anti-IL-33 or anti-ST2 reversed the effect of IL-33 on facilitating skin wound closure, suggesting that IL-33 administration facilitated skin wound closure through the IL-33/ST2 signaling pathway. Collectively, these findings indicate that the detection of IL-33/ST2 might be a reliable biomarker for the determination of skin wound age in forensic practice.

Increased expression of CSF1 in patients with eosinophilic asthma

BACKGROUND

The link between colony-stimulating factor 1 (CSF1) and asthma was reported recently. However, the role and mechanism of CSF1 in asthma remain poorly understood. In this study, we aimed to explore the expression and its potential mechanism of CSF1 in asthma.

METHODS

CSF1 expression in the airway samples from asthmatics and healthy controls were examined, then the correlations between CSF1 and eosinophilic indicators were analyzed. Subsequently, bronchial epithelial cells (BEAS-2B) with CSF1 overexpression and knockdown were constructed to investigate the potential molecular mechanism of CSF1. Finally, the effect of CSF1R inhibitor on STAT1 was investigated.

RESULTS

The expression of CSF1 was significantly increased in patients with asthma compared to healthy controls, especially in patients with severe and eosinophilic asthma. Upregulated CSF1 positively correlated with airway-increased eosinophil inflammation. In vitro, cytokines interleukin 13 (IL-13) and IL-33 can stimulate the upregulation of CSF1 expression. CSF1 overexpression enhanced p-CSF1R/CSF1R and p-STAT1/STAT1 expression, while knockdown CSF1 using anti-CSF1 siRNAs decreased p-CSF1R/CSF1R and p-STAT1/STAT1 expression. Furthermore, the inhibitor of CSF1R significantly decreased p-STAT1/STAT1 expression.

CONCLUSIONS

Sputum CSF1 may be involved in asthmatic airway eosinophil inflammation by interacting with CSF1R and further activating the STAT1 signaling. Interfering this potential pathway could serve as an anti-inflammatory therapy for asthma.

New Concepts in Barrier Dysfunction in CRSwNP and Emerging Roles of Tezepelumab and Dupilumab

BACKGROUND

Epithelial barrier disturbances in CRSwNP patients play an important role in both the innate and adaptive immune responses, contributing to chronic inflammation, olfactory dysfunction, and impairments in quality of life.

OBJECTIVE

To evaluate the role of the sinonasal epithelium in disease and health, review the pathophysiology of epithelial barrier dysfunction in CRSwNP, and the immunologic targets for treatment.

METHODS

Literature review.

RESULTS

Blockade of cytokines such as thymic stromal lymphopoietin (TSLP), IL-4, and IL-13 have shown promise in barrier restoration and IL-13, specifically may be central to olfactory dysfunction.

CONCLUSION

The sinonasal epithelium plays a crucial role in the health and function of the mucosa and immune response. Increased understanding of the local immunologic dysfunction has led to several therapeutics that can potentially restore epithelial barrier function and olfaction. Real world and comparative effectiveness studies are needed.

Development of an inhaled anti-TSLP therapy for asthma

Thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine, acts as a key mediator in airway inflammation and modulates the function of multiple cell types, including dendritic cells and group 2 innate lymphoid cells. TSLP plays a role in asthma pathogenesis as an upstream cytokine, and data suggest that TSLP blockade with the anti-TSLP monoclonal antibody, tezepelumab, could be efficacious in a broad asthma population. Currently approved asthma biologic therapies target allergic or eosinophilic disease and require phenotyping; therefore, an unmet need exists for a therapy that can address Type 2 (T2)-high and T2-low inflammation in asthma. All currently approved biologic treatments are delivered intravenously or subcutaneously; an inhaled therapy route that allows direct targeting of the lung with reduced systemic impact may offer advantages. Currently in development, ecleralimab (CSJ117) represents the first inhaled anti-TSLP antibody fragment that binds soluble TSLP and prevents TSLP receptor activation, thereby inhibiting further inflammatory signalling cascades. This anti-TSLP antibody fragment is being developed for patients with severe uncontrolled asthma despite standard of care inhaled therapy. A Phase IIa proof of concept study, using allergen bronchoprovocation as a model for asthma exacerbations, found that ecleralimab was well-tolerated and reduced allergen-induced bronchoconstriction in adult patients with mild asthma. These results suggest ecleralimab may be a promising, new therapeutic class for asthma treatment.

Sounding the alarmins-The role of alarmin cytokines in asthma

The alarmin cytokines thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 are epithelial cell-derived mediators that contribute to the pathobiology and pathophysiology of asthma. Released from airway epithelial cells exposed to environmental triggers, the alarmins drive airway inflammation through the release of predominantly T2 cytokines from multiple effector cells. The upstream positioning of the alarmins is an attractive pharmacological target to block multiple T2 pathways important in asthma. Blocking the function of TSLP inhibits allergen-induced responses including bronchoconstriction, airway hyperresponsiveness, and inflammation, and subsequent clinical trials of an anti-TSLP monoclonal antibody, tezepelumab, in asthma patients demonstrated improvements in lung function, airway responsiveness, inflammation, and importantly, a reduction in the rate of exacerbations. Notably, these improvements were observed in patients with T2-high and with T2-low asthma. Clinical trials blocking IL-33 and its receptor ST2 have also shown improvements in lung function and exacerbation rates; however, the impact of blocking the IL-33/ST2 axis in T2-high versus T2-low asthma is unclear. To date, there is no evidence that IL-25 blockade is beneficial in asthma. Despite the considerable overlap in the cellular functions of IL-25, IL-33, and TSLP, they appear to have distinct roles in the immunopathology of asthma.

The Role of TSLP in Atopic Dermatitis: From Pathogenetic Molecule to Therapeutical Target

Atopic dermatitis (AD) is a kind of chronic skin disease with inflammatory infiltration, characterized by skin barrier dysfunction, immune response dysregulation, and skin dysbiosis. Thymic stromal lymphopoietin (TSLP) acts as a regulator of immune response, positively associated with AD deterioration. Mainly secreted by keratinocytes, TSLP interacts with multiple immune cells (including dendritic cells, T cells, and mast cells), following induction of Th2-oriented immune response during the pathogenesis of AD. This article primarily focuses on the TSLP biological function, the relationship between TSLP and different cell populations, and the AD treatments targeting TSLP.

Multiscale 3D genome organization underlies ILC2 ontogenesis and allergic airway inflammation

Innate lymphoid cells (ILCs) are well-characterized immune cells that play key roles in host defense and tissue homeostasis. Yet, how the three-dimensional (3D) genome organization underlies the development and functions of ILCs is unknown. Herein, we carried out an integrative analysis of the 3D genome structure, chromatin accessibility and gene expression in mature ILCs. Our results revealed that the local 3D configuration of the genome is rewired specifically at loci associated with ILC biology to promote their development and functional differentiation. Importantly, we demonstrated that the ontogenesis of ILC2s and the progression of allergic airway inflammation are determined by a unique local 3D configuration of the region containing the ILC-lineage-defining factor Id2, which is characterized by multiple interactions between the Id2 promoter and distal regulatory elements bound by the transcription factors GATA-3 and RORα, unveiling the mechanism whereby the Id2 expression is specifically controlled in group 2 ILCs.

Recent Advancement and Novel Application of Natural Polyphenols for the Treatment of Allergy Asthma: From Phytochemistry to Biological Implications

Allergic diseases, primarily IgE-mediated, exert a substantial global health burden. A pivotal role in allergic reactions is played by mast cells, with histamine serving as a central mediator. Within this context, plant-based polyphenols, abundantly present in vegetables and fruits, show promising potential for allergy prevention. These natural compounds, particularly flavonoids, possess anti-inflammatory and anti-allergic properties, influencing dendritic cells, modulating macrophages, and fostering the proliferation of B cells and T cells. The potent anti-allergic effects of flavonoids are attributed to their ability to reduce the production of signaling factors, suppress cytokine production, and regulate signal transduction and gene expression in mast cells, basophils, and T cells. Notably, their benefits extend beyond allergy prevention, as they hold promise in the prevention and treatment of autoimmune illnesses such as diabetes, rheumatoid arthritis, and multiple sclerosis. In the context of allergic reactions and autoimmune diseases, polyphenols exhibit immunomodulatory effects by inhibiting autoimmune T cell proliferation and downregulating pro-inflammatory cytokines. In recent times, flavonoids, being the most prevalent polyphenols in food, have garnered significant attention from researchers due to their potential health advantages. This review compiles the latest scientific research to highlight the impact of flavonoids on allergic illnesses and their potential as a beneficial dietary component.

Nasal TSLP and periostin in infants with severe bronchiolitis and risk of asthma at 4 years of age

BACKGROUND

Severe bronchiolitis is often associated with subsequent respiratory morbidity, mainly recurrent wheezing and asthma. However, the underlying immune mechanisms remain unclear. The main goal of this study was to investigate the association of nasal detection of periostin and thymic stromal lymphopoietin (TSLP) during severe bronchiolitis with the development of asthma at 4 years of age.

METHODS

Observational, longitudinal, post-bronchiolitis, hospital-based, follow-up study. Children hospitalized for bronchiolitis between October/2013 and July/2017, currently aged 4 years, included in a previous study to investigate the nasal airway secretion of TSLP and periostin during bronchiolitis, were included. Parents were contacted by telephone, and were invited to a clinical interview based on a structured questionnaire to obtain information on the respiratory evolution. The ISAAC questionnaire for asthma symptoms for 6-7-year-old children, was also employed.

RESULTS

A total of 248 children were included (median age 4.4 years). The mean age at admission for bronchiolitis was 3.1 (IQR: 1.5-6.5) months. Overall, 21% had ever been diagnosed with asthma and 37% had wheezed in the last 12 months. Measurable nasal TSLP was detected at admission in 27(11%) cases and periostin in 157(63%). The detection of nasal TSLP was associated with the subsequent prescription of maintenance asthma treatment (p = 0.04), montelukast (p = 0.01), and the combination montelukast/inhaled glucocorticosteroids (p = 0.03). Admissions for asthma tended to be more frequent in children with TSLP detection (p = 0.07). In the multivariate analysis, adjusting for potential confounders, the detection of TSLP remained independently associated with chronic asthma treatment prescription (aOR:2.724; CI 1.051-7.063, p:0.04) and with current asthma (aOR:3.41; CI 1.20-9.66, p:0.02). Nasal detection of periostin was associated with lower frequency of ever use of short-acting beta2-agonists (SABA) (p = 0.04), lower prevalence of current asthma (p = 0.02), less prescription of maintenance asthma treatment in the past 12 months (p = 0.02, respectively). In the multivariate analysis, periostin was associated with lower risk of asthma at 4 years, independently of the atopic status (aOR:0.511 CI 95% 0.284-0.918, p:0.025).

CONCLUSIONS

Our results show a positive correlation between nasal TSLP detection in severe bronchiolitis and the presence of current asthma, prescription of asthma maintenance treatment and respiratory admissions up to the age of 4 years. By contrast, we found a protective association between nasal periostin detection and current asthma at 4 years, ever diagnosis of asthma, maintenance asthma treatment prescription, and respiratory admissions.

Selective induction of thymic stromal lymphopoietin expression by novel nitrogen-containing steroid compounds in PAM-212 cells

Background

Thymic stromal lymphopoietin (TSLP) has been shown to be able to amplify Tregs. Thus, TSLP induction has the potential to induce endogenous Tregs and control autoimmunity. In the previous research, we found that a new compound named 02F04 can induce TSLP production while simultaneously activating the liver X receptor (LXR). Because LXR activation leads to a decrease in Treg, we attempted to find a 02F04-derivative, druggable lead compound with a basic skeleton that induces TSLP production without activating LXR. As the results, we found HA-7 and HA-19 and, in this study, examined the molecular mechanisms in TSLP production.

Methods

A murine keratinocyte cell line PAM 212 was stimulated with HA-7 and HA-19, and then the expressions of cytokines were examined via ELISA and real-time fluorescence quantitative PCR.

Results

HA-7 and HA-19 induced TSLP production but almost not the expression of TNF-α, IL-13, IL-25, and IL-33 in PAM212 cells. These compounds inhibited LXR activities. The TSLP expression induced by HA-7 and HA-19 was inhibited by the Gq/11 inhibitor YM-254890, ROCK inhibitor Y-27632, and ERK inhibitor U0126. HA-7 and HA-19 also induced the formation of stress fiber and ERK phosphorylation, which were inhibited by YM-254890 and Y-27632.

Conclusions

Our findings indicated that HA-7 and HA-19 selectively induced TSLP production in PAM212 via Gq/11, Rho/ROCK and ERK pathways. Our findings also indicated that TSLP expression was differentially regulated from other cytokines, and the selective expression could be induced with low-molecular-weight compounds such as HA-7 and HA-19.

Role of Chemokines and Inflammatory Cells in Respiratory Allergy

The idea of "one airway, one disease" has been gaining importance in the last decade. In the upper and lower airways, allergic mechanisms interact with each other. In the initial stage of respiratory allergic inflammation, allergens contact the respiratory epithelium, which produces chemokines and inflammatory factors, which cause allergic reactions by binding to the corresponding receptors and chemotactic various inflammatory cells to reach the epithelium and tissues. It also drives inflammatory cells to activate and produce more inflammatory factors, thus producing a cascade amplification effect. Inflammatory cell aggregation and activation are very complex and interact with each other in a lattice structure. By blocking the action of various chemokines, inflammatory cell aggregation is reduced, and ultimately the symptoms of respiratory allergy are alleviated. Chemokines can serve as cues for coordinated recruitment of immune cells into and out of tissues, as well as directing the spatial organization of immune cells within tissues and cellular interactions. Chemokines are critical in directing immune cell migration and thus have an important role in the direction of respiratory allergy: however, chemokines are also involved in the production and recruitment of immune cells that contribute to respiratory allergy. In this article, linking the upper and lower respiratory tracts. We review the role of the chemokine system in the respiratory immune response and discuss how respiratory disease modulates overall chemokines to shape the type and outcome of the immune response to the treatment of respiratory allergic disease so that we can further deepen our knowledge of chemokines in the direction of respiratory allergy. In the future, we can do drug research and development based on this network structure and explore new research directions.