Interleukin-13: central mediator of allergic asthma

Emerging Concepts in Cytokine Regulation of Airway Remodeling in Asthma

Asthma, a chronic respiratory condition that has seen a dramatic rise in prevalence over the past few decades, now affects more than 300 million people globally and imposes a significant burden on healthcare systems. The key pathological features of asthma include inflammation, airway hyperresponsiveness, mucus cell metaplasia, smooth muscle hypertrophy, and subepithelial fibrosis. Cytokines released by lung epithelial cells, stromal cells, and immune cells during asthma are critical to pathological tissue remodeling in asthma. Over the past few decades, researchers have made great strides in understanding key cells involved in asthma and the cytokines that they produce. Epithelial cells as well as many adaptive and innate immune cells are activated by environmental signals to produce cytokines, namely, type 2 cytokines (IL-4, IL-5, IL-13), IFN-γ, IL-17, TGF-β, and multiple IL-6 family members. However, the precise mechanisms through which these cytokines contribute to airway remodeling remain elusive. Additionally, multiple cell types can produce the same cytokines, making it challenging to decipher how specific cell types and cytokines uniquely contribute to asthma pathogenesis. This review highlights recent advances and provides a comprehensive overview of the key cells involved in the production of cytokines and how these cytokines modulate airway remodeling in asthma.

Innate Immunity and Asthma Exacerbations: Insights From Human Models

Asthma is a common chronic respiratory disease characterized by the presence of airway inflammation, airway hyperresponsiveness, and mucus hypersecretion. Repeated asthma exacerbations can lead to progressive airway remodeling and irreversible airflow obstruction. Thus, understanding and preventing asthma exacerbations are of paramount importance. Although multiple endotypes exist, asthma is most often driven by type 2 airway inflammation. New therapies that target specific type 2 mediators have been shown to reduce the frequency of asthma exacerbations but are incompletely effective in a significant number of asthmatics. Furthermore, it remains unknown whether current treatments lead to sustained changes in the airway or if targeting additional pathways may be necessary to achieve asthma remission. Activation of innate immunity is the initial event in the inflammatory sequence that occurs during an asthma exacerbation. However, there continue to be critical gaps in our understanding of the innate immune response to asthma exacerbating factors. In this review, we summarize the current understanding of the role of innate immunity in asthma exacerbations and the methods used to study them. We also identify potential novel therapeutic targets for asthma and future areas for investigation.

Xenotropic and polytropic retrovirus receptor 1 (XPR1) promotes progression of papillary thyroid carcinoma via the BRAF-ERK1/2-P53 signaling pathway

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Xenotropic and polytropic retrovirus receptor 1 (XPR1), identified as a cellular receptor, plays roles in many pathophysiological processes. However, the underlying function and molecular mechanisms of XPR1 in PTC remain unclear. Therefore, this study aimed to elucidate the role of XPR1 in the process of PTC and the potential mechanisms.

METHODS

RNA-sequencing was performed for gene differential expression analysis in PTC patients' tissues. Immunohistochemical assay, real-time PCR, and western blotting assay were used to determine the expression of XPR1, BRAF, and P53 in PTC tissues. The function of XPR1 on the progression of PTC was explored using in vitro and in vivo experiments. The molecular mechanism of XPR1 was investigated using gene silencing, ELISA, immunofluorescence, western blotting, and real-time PCR assays.

RESULTS

We found that XPR1 was markedly upregulated in PTC tissues compared to adjacent noncancerous tissues, suggesting that high expression of XPR1 could be correlated with poor patient disease-free survival in PTC. In addition, the expression of BRAF and P53 in PTC tissues was substantially higher than in adjacent noncancerous tissues. Silencing of XPR1 reduced the proliferation, migration, and invasion capacities of TPC-1 cells in vitro and effectively inhibited the tumorigenecity of PTC in vivo. More importantly, silencing of XPR1 in TPC-1 cells significantly decreased the expression of XPR1, BRAF, and P53 both in vitro and in vivo. Interestingly, we demonstrated that XPR1 may positively activate the BRAF-ERK-P53 signaling pathway, further promoting PTC progression.

CONCLUSION

The findings reveal a crucial role of XPR1 in PTC progression and prognosis via the BRAF-ERK1/2-P53 signaling pathway, providing potential therapeutic targets for treating PTC.

Leptin augments IL-13-induced airway eotaxins and submucosal eosinophilia in obesity-associated asthma

BACKGROUND

Airway tissue eosinophilia can be an observed feature of obesity-associated type 2 (T2) asthma, but the processes mediating this inflammation are unknown.

OBJECTIVE

To investigate a process whereby leptin, an adipokine elevated in obesity, potentiates pulmonary eosinophilia and eotaxin production by airway fibroblasts in T2 asthma.

METHODS

We assessed associations between body mass index and airway eosinophilia as well as leptin and eotaxin production in 82 participants with asthma, 37 of whom exhibited obesity. Cultured human airway fibroblasts and mouse models of chronic allergic airway disease were used to evaluate leptin's effect on eotaxin production and lung eosinophilia. The role of IL-13 receptor alpha 2 (IL-13Rα2) in mediating these processes was examined using specific neutralizing antibodies in vitro.

RESULTS

In participants with T2 asthma and obesity, we observed that airway tissue eosinophilia did not associate with traditional T2 inflammation metrics such as peripheral and/or bronchoalveolar lavage fluid eosinophil counts or with fractional exhaled nitric oxide. Alternatively, we observed elevated bronchoalveolar lavage fluid leptin and eotaxin-1 levels. In airway fibroblasts from participants with asthma, leptin augmented IL-13-induced eotaxin-1 and eotaxin-3 production and IL13RA2 expression. In mice, elevated leptin promoted airway IL-13Rα2 and eotaxin production by lung fibroblasts and lung tissue eosinophilia following chronic house dust mite allergen exposure. Inhibition of IL-13Rα2 reduced combined leptin and IL-13-stimulated eotaxin secretion by human airway fibroblasts.

CONCLUSIONS

We identified a potential association explaining airway tissue eosinophil retention in obesity-associated T2 asthma through leptin-mediated enhancement of IL-13-induced eosinophil chemokine production by airway fibroblasts, a process requiring IL-13Rα2.

Tissue-Resident Th2 Cells in Type 2 Immunity and Allergic Diseases

Type 2 immunity represents a unique immune module that provides host protection against macro-parasites and noxious agents such as venoms and toxins. In contrast, maladaptive type 2 immune responses cause allergic diseases. While multiple cell types play important roles in type 2 immunity, recent studies in humans and murine models of chronic allergic diseases have shown that a distinct population of tissue-resident, CD4+ T helper type 2 (Th2) cells play a critical role in chronic allergic inflammation. The rules regulating Th2 cell differentiation have remained less well defined than other T cell subsets, but recent studies have shed new light into the specific mechanisms controlling Th2 cell biology in vivo. Here, we review our current understanding of the checkpoints regulating the development and function of tissue-resident Th2 cells with a focus on chronic allergic diseases. We discuss evidence for a barrier tissue checkpoint in initial Th2 cell priming, including the role of neuropeptides, damage-associated molecular patterns, and dendritic cell macro-clusters. Furthermore, we review the evidence for a second barrier tissue checkpoint that instructs the development of multi-cytokine producing, tissue-resident Th2 cells that orchestrate allergic inflammation. Lastly, we discuss potential approaches to therapeutically target tissue-resident Th2 cells in chronic allergic diseases.

Selective JAK1 inhibitors and the therapeutic applications thereof: a patent review (2016-2023)

INTRODUCTION

The family of Janus kinases (JAKs) consists of four intracellular non-receptor tyrosine kinases: JAK1, JAK2, JAK3, and tyrosine kinase 2 (TYK2). Among these four subtypes, JAK1 is the only isoform that can form heterodimers with all three JAKs, and JAK1 dysfunction can lead to inflammation and severe autoimmune diseases. Interest in JAK1 inhibitors has grown tremendously, and the number of inhibitors targeting JAK1 continues to rise annually.

AREAS COVERED

This paper reviews JAK1 small molecule inhibitors that were reported in patent literature from January 2016 to December 2023. Web of Science, SciFinder, PubMed, WIPO, EPO, USPTO, and CNIPA databases were used for searching the literature and patents for JAK1 inhibitors.

EXPERT OPINION

JAK1 inhibitors show great promise in treating cytokine dysregulated disorders; nevertheless, nonselective JAK1 inhibitors have more severe side effects, which restricts the therapy's safety and use. Therefore, developing highly selective JAK1 inhibitors can mitigate potential risks and lead to next-generation therapies with improved efficacy and safety profiles.

Role of the TGF-β cytokine and its gene polymorphisms in asthma etiopathogenesis

Transforming growth factor beta (TGF-β) is a pluripotent cytokine expressed by all cells of the human body which plays important roles in maintaining homeostasis and allowing for proper individual development. Disturbances in TGF-β signaling contribute to the development of many diseases and disorders, including cancer and organ fibrosis. One of the diseases with the best-characterized correlation between TGF-β action and etiopathogenesis is asthma. Asthma is the most common chronic inflammatory disease of the lower and upper respiratory tract, characterized by bronchial hyperresponsiveness to a number of environmental factors, leading to bronchospasm and reversible limitation of expiratory flow. TGF-β, in particular TGF-β1, is a key factor in the etiopathogenesis of asthma. TGF-β1 concentration in bronchoalveolar lavage fluid samples is elevated in atopic asthma, and TGF-β expression is increased in asthmatic bronchial samples. The expression of all TGF-β isoforms is affected by a number of single nucleotide polymorphisms found in the genes encoding these cytokines. Some of the SNPs that alter the level of TGF-β expression may be associated with the occurrence and severity of symptoms of asthma and other diseases. The TGF-β gene polymorphisms, which are the subject of this paper, are potential diagnostic factors. If properly used, these polymorphisms can facilitate the early and precise diagnosis of asthma, allowing for the introduction of appropriate therapy and reduction of asthma exacerbation frequency.

Network Pharmacology and Molecular Docking Reveal Anti-Asthmatic Potential of Zephyranthes rosea Lindl. in an Ovalbumin-Induced Asthma Model

Background: This study aimed to evaluate the anti-inflammatory effects of a Zephyranthes rosea in an ovalbumin-induced asthma model. Methods: Allergic asthma was induced in mice via intraperitoneal injection, followed by intranasal ovalbumin challenge. Methanolic extract of Z. rosea bulb was orally administered to asthmatic mice for 14 days. Hematological parameters for bronchoalveolar lavage fluid (BALF) and blood were analyzed. The mRNA expression levels of interleukins and transforming growth factor beta (TGF-β1) in lung tissues were determined using reverse transcriptase-polymerase chain reaction (RT-PCR). Network pharmacology analysis was used to find possible Z. rosea targets. After building a protein-protein interaction network to find hub genes, GO and KEGG enrichment analyses were carried out to determine the potential mechanism. In silico analysis was performed by Molecular Operating Environment. Results: GC-MS analysis of Z. rosea extract detected major classes of phytochemicals. Hematological parameters in blood and BALF from Z. rosea extract-treated animals were significantly reduced in a dose-dependent fashion. Histopathology revealed that Z. rosea bulb had an ameliorative effect on lung tissues. Moreover, treatment with Z. rosea bulb extract significantly restored the normal levels of IL-4, IL-6, IL-1β, IL-10, IL-13, and TGF-β1 in allergic asthmatic mice compared to the diseased group. In silico analysis, particularly of the binding affinities of Z. rosea bulb phytoconstituents for IL6, AKT1, and Src, supported in vivo results. Conclusions: These findings indicated that Z. rosea bulb extract significantly ameliorates cellular and molecular biomarkers of bronchial inflammation and could be a potential candidate for treating allergic asthma.

Therapeutic potential of anticancer activity of nitrogen-containing heterocyclic scaffolds as Janus kinase (JAK) inhibitor: Biological activity, selectivity, and structure-activity relationship

The JAK-STAT signalling pathway is primarily involved in cytokine signalling and induces various factors namely, erythropoietin, thrombopoietin, interferons, interleukins, and granulocyte colony-stimulating factors. These factors tremendously influenced understanding human health and illness, specifically cancer. Inhibiting the JAK/STAT pathway offers enormous therapeutic promises against cancer. Many JAK inhibitors are now being studied due to their efficacy in various cancer treatments. Further, the Nitrogen-heterocyclic (N-heterocyclic) scaffold has always shown to be a powerful tool for designing and discovering synthetic compounds with diverse pharmacological characteristics. The review focuses on several FDA-approved JAK inhibitors and their systematic categorization. The medicinal chemistry perspective is highlighted and classified review on the basis of N-heterocyclic molecules. Several examples of designing strategies of N-heterocyclic rings including pyrrolo-azepine, purine, 1H-pyrazolo[3,4-d]pyrimidine, 1H-pyrrolo[2,3-b]pyridine, pyrazole, thieno[3,2-d] pyrimidine, and, pyrimidine-based derivatives and their structure-activity relationships (SAR) are discussed. Among the various N-heterocyclic-based JAK inhibitors pyrimidine-containing compound 1 exhibited excellent inhibition activity against JAK2WT and mutated-JAK2V617F with IC50 of 2.01 and 18.84 nM respectively. Amino pyrimidine-containing compound 6 and thiopheno[3,2-d]pyrimidine-containing compound 13 expressed admirable JAK3 inhibition activity with IC50 of 1.7 nM and 1.38 nM respectively. Our review will support the medicinal chemists in refining and directing the development of novel N-heterocyclic-based JAK inhibitors.

High-throughput Bronchus-on-a-Chip system for modeling the human bronchus

Airway inflammation, a protective response in the human body, can disrupt normal organ function when chronic, as seen in chronic obstructive pulmonary disease (COPD) and asthma. Chronic bronchitis induces goblet cell hyperplasia and metaplasia, obstructing airflow. Traditional animal testing is often replaced by in vitro three-dimensional cultures of human epithelial cells to assess chronic cell responses. However, these cells are cultured horizontally, differing from the tubular structure of the human airway and failing to accurately reproduce airway stenosis. To address this, we developed the Bronchus-on-a-Chip (BoC) system. The BoC uses a novel microfluidic design in a standard laboratory plate, embedding 62 chips in one plate. Human bronchial epithelial cells were cultured against a collagen extracellular matrix for up to 35 days. Characterization included barrier integrity assays, microscopy, and histological examination. Cells successfully cultured in a tubular structure, with the apical side air-lifted. Epithelial cells differentiated into basal, ciliated, and secretory cells, mimicking human bronchial epithelium. Upon exposure to inducers of goblet cell hyperplasia and metaplasia, the BoC system showed mucus hyperproduction, replicating chronic epithelial responses. This BoC system enhances in vitro testing for bronchial inflammation, providing a more human-relevant and high-throughput method.

Oxidative Stress and Antioxidants in Pediatric Asthma's Evolution and Management

Within the pediatric population, bronchial asthma is one of the most prevalent chronic respiratory system diseases. The number of exacerbations, severity, and duration of symptoms all have a significant impact on children's life quality. In the last decades, the prevention and management strategies of this pathology have focused on maintaining or even increasing the pulmonary function to maximum levels in early childhood, as it has been demonstrated that functional deficits at this level occurring before school age cause pathological manifestations later, in adulthood. The epithelium of the airways and implicitly that of the lung is the first barrier against the lesions caused by pro-oxidative factors. Both oxidative and antioxidative factors can be of endogenous origin (produced by the body) or exogenous (from the environment or diet). Good functioning of antioxidant defense mechanisms from the molecular level to the tissue level, and a balance between pro-oxidative factors and anti- oxidative factors, influence the occurrence of compensatory mechanisms at the level of the respiratory epithelium, causing the delay of local responses to the stress induced by chronic inflammation (bronchial remodeling, thickening of airway smooth muscles, bronchoconstriction, bronchial hyper-reactivity). These mechanisms underlie the pathophysiological changes in asthma. Numerous studies carried out among the pediatric population inclusively have demonstrated the effectiveness of antioxidants in the prophylaxis, slowing down and preventing the progression of this pathology. This review complements the scientific articles, aiming at emphasizing the complexity of oxidative physio-pathological pathways and their importance in the occurrence, development, and therapeutic response in asthma, providing a good understanding of the relationship between oxidative and antioxidative factors, and being a source of future therapeutic strategies.

Cell line-based in vitro models of normal and chronic bronchitis-like airway mucosa to study the toxic potential of aerosolized palladium nanoparticles

Background

Physiologically relevant cell line-based models of human airway mucosa are needed to assess nanoparticle-mediated pulmonary toxicity for any xenbiotics expsoure study. Palladium nanoparticles (Pd-NP) originating from catalytic converters in vehicles pose health risks. We aimed to develop in vitro airway models to assess the toxic potential of Pd-NP in normal (Non-CB) and chronic bronchitis-like (CB-like) mucosa models.

Methods

Bronchial mucosa models were developed using Epithelial cells (16HBE: apical side) co-cultured with fibroblast (basal side) at an air-liquid interface. Furthermore, both Non-CB and CB-like (IL-13 treatment) models with increased numbers of goblet cells were used. The models were exposed to 3 different doses of aerosolized Pd-NP (0.2, 0.3, and 6 μg/cm2) using XposeALI® and clean air as a control. After 24 h of incubation, the expression of inflammatory (IL6, CXCL8, TNFα, and NFKB), oxidative stress (HMOX1, SOD3, GPx, and GSTA1), and tissue injury/repair (MMP9/TIMP1) markers was assessed using qRT-PCR. The secretion of CXCL-8 and the expression of a tissue injury/repair marker (MMP-9) were measured via ELISA.

Results

Significantly (p < 0.05) increased expressions of CXCL8, IL6, and NFKB were observed at the highest dose of Pd-NP in CB-like models. However, in Non-CB mucosa models, a maximum effect on TNFα and NFKB expression was observed at a medium Pd-NP dose. In Non-CB mucosa models, SOD3 showed a clear dose-dependent response to Pd-NP exposure, while GSTA1 expression was significantly increased (p < 0.05) only at the lowest dose of Pd-NP. The secretion of CXCL-8 increased in a dose-dependent manner in the Non-CB mucosa models following exposure to Pd-NP. In CB-like models, exposure to high concentrations of Pd-NP significantly increased the release of MMP-9 compared to that in other exposure groups.

Conclusion

The combination of our Non-CB and CB-like mucosa models with the XposeALI® system for aerosolized nanoparticle exposure closely mimics in vivo lung environments and cell-particle interactions. Results from these models, utilizing accessible cell lines, will maximize the reliability of in vitro findings in human health risk assessment.

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

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

A 12-week double-blind randomised controlled trial investigating the effect of dietary supplementation with 125 μg/d vitamin D in adults with asthma

Vitamin D deficiency has previously been linked to higher rates of exacerbation and reduced lung function in asthmatics. Previous randomised controlled trials investigating the effect of vitamin D supplementation have mainly focused on children with asthma. Trials involving adults have typically used bolus dosing regimens, and the main outcomes have been patient-focused without investigating underlying inflammation. The present study aimed to conduct a 12-week placebo-controlled randomised controlled trials administering a daily 125 µg vitamin D3 supplement to adults with mild to moderate asthma. A total of 32 participants were randomised to receive either the 125 μg vitamin D3 supplement or an identical matching placebo. The primary outcome of the study was lung function measured by the ratio of FEV1:FVC (effect size 2·5) with secondary outcomes including asthma symptoms and inflammatory biomarkers. There was a small but statistically significant higher increase in the mean (±sd) ratio of FEV1:FVC from baseline to post-intervention in the vitamin D group (+0·05 ± 0·06) compared with the placebo group (+0·006 ± 0·04, P = 0·04). There was no effect of the intervention on asthma control test scores, or the inflammatory biomarkers measured. There was a moderate, significant association between baseline plasma 25(OH)D concentration and baseline plasma IL-10 (r = 0·527, P = 0·005) and TNF-α (r = −0·498. P = 0·008) concentrations. A daily vitamin D3 supplement led to slightly improved lung function in adult asthmatics and may be a useful adjunct to existing asthma control strategies, particularly for individuals with suboptimal vitamin D status.

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

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

IL-13 induces loss of CFTR in ionocytes and reduces airway epithelial fluid absorption

The airway surface liquid (ASL) plays a crucial role in lung defense mechanisms, and its composition and volume are regulated by the airway epithelium. The cystic fibrosis transmembrane conductance regulator (CFTR) is abundantly expressed in a rare airway epithelial cell type called an ionocyte. Recently, we demonstrated that ionocytes can increase liquid absorption through apical CFTR and basolateral barttin/chloride channels, while airway secretory cells mediate liquid secretion through apical CFTR channels and basolateral NKCC1 transporters. Th2-driven (IL-4/IL-13) airway diseases, such as asthma, cause goblet cell metaplasia, accompanied by increased mucus production and airway secretions. In this study, we investigate the effect of IL-13 on chloride and liquid transport performed by ionocytes. IL-13 treatment of human airway epithelia was associated with reduced epithelial liquid absorption rates and increased ASL volume. Additionally, IL-13 treatment reduced the abundance of CFTR-positive ionocytes and increased the abundance of CFTR-positive secretory cells. Increasing ionocyte abundance attenuated liquid secretion caused by IL-13. Finally, CFTR-positive ionocytes were less common in asthma and chronic obstructive pulmonary disease and were associated with airflow obstruction. Our findings suggest that loss of CFTR in ionocytes contributes to the liquid secretion observed in IL-13-mediated airway diseases.

IL-13 and IL-17A activate β1 integrin through an NF-kB/Rho kinase/PIP5K1γ pathway to enhance force transmission in airway smooth muscle

Integrin activation resulting in enhanced adhesion to the extracellular matrix plays a key role in fundamental cellular processes. Although integrin activation has been extensively studied in circulating cells such as leukocytes and platelets, much less is known about the regulation and functional impact of integrin activation in adherent cells such as smooth muscle. Here, we show that two different asthmagenic cytokines, IL-13 and IL-17A, activate type I and IL-17 cytokine receptor families, respectively, to enhance adhesion of airway smooth muscle. These cytokines also induce activation of β1 integrins detected by the conformation-specific antibody HUTS-4. Moreover, HUTS-4 binding is increased in the smooth muscle of patients with asthma compared to nonsmokers without lung disease, suggesting a disease-relevant role for integrin activation in smooth muscle. Indeed, integrin activation induced by the β1-activating antibody TS2/16, the divalent cation manganese, or the synthetic peptide β1-CHAMP that forces an extended-open integrin conformation dramatically enhances force transmission in smooth muscle cells and airway rings even in the absence of cytokines. We demonstrate that cytokine-induced activation of β1 integrins is regulated by a common pathway of NF-κB-mediated induction of RhoA and its effector Rho kinase, which in turn stimulates PIP5K1γ-mediated synthesis of PIP2 at focal adhesions, resulting in β1 integrin activation. Taken together, these data identify a pathway by which type I and IL-17 cytokine receptor family stimulation induces functionally relevant β1 integrin activation in adherent smooth muscle and help to explain the exaggerated force transmission that characterizes chronic airway diseases such as asthma.

The role of IL-2 cytokine family in asthma

BACKGROUND

The interleukin-2 (IL-2) family of cytokines, including IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21, are pivotal regulators of the immune response, impacting both innate and adaptive immunity. Understanding their molecular characteristics, receptor interactions, and signalling pathways is essential for elucidating their roles in health and disease.

OBJECTIVES

This review provides a comprehensive overview of the IL-2 family of cytokines, highlighting their molecular biology, receptor interactions, and signalling mechanisms. Furthermore, it explores the involvement of IL-2 family cytokines in the pathogenesis of chronic respiratory diseases, with a specific focus on chronic obstructive pulmonary disease (COPD) and asthma.

METHODS

A thorough literature review was conducted to gather insights into the molecular biology, receptor interactions, and signalling pathways of IL-2 family cytokines. Additionally, studies investigating the roles of these cytokines in chronic respiratory diseases, particularly COPD and asthma, were analysed to discern their implications in wider pathophysiology of disease.

RESULTS

IL-2 family cytokines exert pleiotropic effects on immune cells, modulating cellular proliferation, differentiation, and survival. Dysregulation of IL-2 family cytokines has been implicated in the pathogenesis of chronic respiratory illnesses, including COPD and asthma. Elevated levels of IL-2 and IL-9 have been associated with disease severity in COPD, while IL-4 and IL-9 play crucial roles in asthma pathogenesis by promoting airway inflammation and remodelling.

CONCLUSION

Understanding the intricate roles of IL-2 family cytokines in chronic respiratory diseases provides valuable insights into potential therapeutic targets for these conditions. Targeting specific cytokines or their receptors may offer novel treatment modalities to attenuate disease progression and improve clinical outcomes in patients with COPD and asthma.

Dupilumab prevents nasal epithelial function alteration by IL-4 in vitro: Evidence for its efficacy

BACKGROUND

Chronic rhinosinusitis with nasal polyp (CRSwNP) is a typical type 2 inflammation involving interleukin (IL)-4 and IL-13. Dupilumab is a fully human monoclonal antibody targeting IL-4 receptor α subunit, thereby blocking signaling by both cytokines. Our hypothesis was that IL-4 and IL-13, by inducing a severe epithelial dysregulation, are involved in CRSwNP pathogenesis. This study aimed to evaluate the in vitro direct effect of IL-4, IL-13, and dupilumab on nasal epithelial functions.

METHODS

Nasal polyps and control mucosa from 28 patients, as well as human nasal epithelial cells (HNEC) from 35 patients with CRSwNP were used. Three major epithelial functions were investigated: the epithelial barrier function (characterized by transepithelial electrical resistance measurements and tight junction protein expression), the ciliary motion (characterized by the ciliary beating efficiency index), and wound healing (characterized by the wound repair rate) under various stimulations (IL-4, IL-13, and dupilumab). The main outcome was a significant change in epithelial functions following exposure to IL-4, IL-13, and dupilumab for 48 h in the basal media.

RESULTS

IL-4 (1, 10, and 100 ng/mL) but not IL-13 induced a significant decrease in occludin and zonula-occludens protein expression, ciliary beating efficiency, and wound repair rate in HNEC. Dupilumab (0.04 mg/mL) had no effect on HNEC and specifically restored all epithelial functions altered when cells were exposed to a 48-h IL-4 stimulation.

CONCLUSION

Dupilumab, in vitro, restored epithelial integrity by counteracting the effect of IL-4 on the epithelial barrier (increased epithelial permeability, decreased ciliary beating efficiency, and decreased wound repair rate).

Eosinophil-mucus interplay in severe asthma: Implications for treatment with biologicals

Airway mucus is a hydrogel with unique biophysical properties due to its primary water composition and a small proportion of large anionic glycoproteins or mucins. The predominant mucins in human mucus, MUC5AC and MUC5B, are secreted by specialized cells within the airway epithelium both in normal conditions and in response to various stimuli. Their relative proportions are correlated with specific inflammatory responses and disease mechanisms. The dysregulation of mucin expression is implicated in numerous respiratory diseases, including asthma, COPD, and cystic fibrosis, where the pathogenic role of mucus has been extensively described yet often overlooked. In airway diseases, excessive mucus production or impaired mucus clearance leads to mucus plugging, with secondary airway occlusion that contribute to airflow obstruction, asthma severity and poor control. Eosinophils and Charcot Leyden crystals in sputum contribute to the mucus burden and tenacity. Mucin may also contribute to eosinophil survival. Other mechanisms, including eosinophil-independent IL-13 release, mast-cell activation and non-type-2 (T2) cytokines, are also likely to participate in mucus pathobiology. An accurate assessment of mucus and its clinical and functional consequences require a thorough approach that includes evaluation of cellular predominance in sputum, airway cytokines and other inflammatory markers, mucus characteristics and composition and structural and functional impact measured by advanced lung imaging. This review, illustrated with clinical scenarios, provides an overview of current methods to assess mucus and its relevance to the choice of biologics to treat patients with severe asthma.

Gene editing in allergic diseases: Identification of novel pathways and impact of deleting allergen genes

Gene editing technology has emerged as a powerful tool in all aspects of health research and continues to advance our understanding of critical and essential elements in disease pathophysiology. The clustered regularly interspaced short palindromic repeats (CRISPR) gene editing technology has been used with precision to generate gene knockouts, alter genes, and identify genes that cause disease. The full spectrum of allergic/atopic diseases, in part because of shared pathophysiology, is ripe for studies with this technology. In this way, novel culprit genes are being identified and allow for manipulation of triggering allergens to reduce allergenicity and disease. Notwithstanding current limitations on precision and potential off-target effects, newer approaches are rapidly being introduced to more fully understand specific gene functions as well as the consequences of genetic manipulation. In this review, we examine the impact of editing technologies of novel genes relevant to peanut allergy and asthma as well as how gene modification of common allergens may lead to the deletion of allergenic proteins.

Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma

Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.

Airway basal stem cells are necessary for the maintenance of functional intraepithelial airway macrophages

Adult stem cells play a crucial role in tissue homeostasis and repair through multiple mechanisms. In addition to being able to replace aged or damaged cells, stem cells provide signals that contribute to the maintenance and function of neighboring cells. In the lung, airway basal stem cells also produce cytokines and chemokines in response to inhaled irritants, allergens, and pathogens, which affect specific immune cell populations and shape the nature of the immune response. However, direct cell-to-cell signaling through contact between airway basal stem cells and immune cells has not been demonstrated. Recently, a unique population of intraepithelial airway macrophages (IAMs) has been identified in the murine trachea. Here, we demonstrate that IAMs require Notch signaling from airway basal stem cells for maintenance of their differentiated state and function. Furthermore, we demonstrate that Notch signaling between airway basal stem cells and IAMs is required for antigen-induced allergic inflammation only in the trachea where the basal stem cells are located whereas allergic responses in distal lung tissues are preserved consistent with a local circuit linking stem cells to proximate immune cells. Finally, we demonstrate that IAM-like cells are present in human conducting airways and that these cells display Notch activation, mirroring their murine counterparts. Since diverse lung stem cells have recently been identified and localized to specific anatomic niches along the proximodistal axis of the respiratory tree, we hypothesize that the direct functional coupling of local stem cell-mediated regeneration and immune responses permits a compartmentalized inflammatory response.

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

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

Defining and targeting mechanisms of eosinophilic inflammation in a new era of severe asthma treatment

Studies using mouse models of airway disease have advanced our understanding of the mechanisms driving eosinophilic airway inflammation and demonstrated potential therapeutic targets in asthma.

The mast cells - Cytokines axis in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disturbance, diagnosed in early childhood. It is associated with varying degrees of dysfunctional communication and social skills, repetitive and stereotypic behaviors. Regardless of the constant increase in the number of diagnosed patients, there are still no established treatment schemes in global practice. Many children with ASD have allergic symptoms, often in the absence of mast cell (MC) positive tests. Activation of MCs may release molecules related to inflammation and neurotoxicity, which contribute to the pathogenesis of ASD. The aim of the present paper is to enrich the current knowledge regarding the relationship between MCs and ASD by providing PPI network analysis-based data that reveal key molecules and immune pathways associated with MCs in the pathogenesis of autism. Network and enrichment analyzes were performed using receptor information and secreted molecules from activated MCs identified in ASD patients. Our analyses revealed cytokines and key marker molecules for MCs degranulation, molecular pathways of key mediators released during cell degranulation, as well as various receptors. Understanding the relationship between ASD and the activation of MCs, as well as the involved molecules and interactions, is important for elucidating the pathogenesis of ASD and developing effective future treatments for autistic patients by discovering new therapeutic target molecules.

Interleukin 13-Induced Inflammation Increases DPP4 Abundance but Does Not Enhance Middle East Respiratory Syndrome Coronavirus Replication in Airway Epithelia

BACKGROUND

Chronic pulmonary conditions such as asthma and chronic obstructive pulmonary disease increase the risk of morbidity and mortality during infection with the Middle East respiratory syndrome coronavirus (MERS-CoV). We hypothesized that individuals with such comorbidities are more susceptible to MERS-CoV infection due to increased expression of its receptor, dipeptidyl peptidase 4 (DPP4).

METHODS

We modeled chronic airway disease by treating primary human airway epithelia with the Th2 cytokine interleukin 13 (IL-13), examining how this affected DPP4 protein levels with MERS-CoV entry and replication.

RESULTS

IL-13 exposure for 3 days led to greater DPP4 protein abundance, while a 21-day treatment raised DPP4 levels and caused goblet cell metaplasia. Surprisingly, despite this increase in receptor availability, MERS-CoV entry and replication were not significantly affected by IL-13 treatment.

CONCLUSIONS

Our results suggest that greater DPP4 abundance is likely not the primary mechanism leading to increased MERS severity in the setting of Th2 inflammation. Transcriptional profiling analysis highlighted the complexity of IL-13-induced changes in airway epithelia, including altered expression of genes involved in innate immunity, antiviral responses, and maintenance of the extracellular mucus barrier. These data suggest that additional factors likely interact with DPP4 abundance to determine MERS-CoV infection outcomes.

The Possible Roles of IL-4/IL-13 in the Development of Eosinophil-Predominant Severe Asthma

Bronchial asthma is characterized by airway inflammation, airway hyperresponsiveness, and reversible airway obstruction. Eosinophils contribute to the pathogenesis of airway disease mainly by releasing eosinophil-specific granules, lipid mediators, superoxide anions, and their DNA. Type-2 cytokines such as interleukin (IL)-4 and IL-13 also play roles in the development of bronchial asthma. Among these cytokines, IL-4 is involved in T-cell differentiation, B-cell activation, B-cell differentiation into plasma cells, and the production of immunoglobulin E. Although IL-13 has similar effects to IL-4, IL-13 mainly affects structural cells, such as epithelial cells, smooth muscle cells, and fibroblasts. IL-13 induces the differentiation of goblet cells that produce mucus and induces the airway remodeling, including smooth muscle hypertrophy. IL-4 and IL-13 do not directly activate the effector functions of eosinophils; however, they can induce eosinophilic airway inflammation by upregulating the expression of vascular cell adhesion molecule-1 (for adhesion) and CC chemokine receptor 3 ligands (for migration). Dupilumab, a human anti-IL-4 receptor α monoclonal antibody that inhibits IL-4 and IL-13 signaling, decreases asthma exacerbations and mucus plugs and increases lung function in moderate to severe asthma. In addition, dupilumab is effective for chronic rhinosinusitis with nasal polyps and for atopic dermatitis, and IL-4/IL-13 blocking is expected to suppress allergen sensitization, including transcutaneous sensitization and atopic march.

IL-13 and IL-17A Activate β1 Integrin through an NF-kB/Rho kinase/PIP5K1γ pathway to Enhance Force Transmission in Airway Smooth Muscle

Integrin activation resulting in enhanced adhesion to the extracellular matrix plays a key role in fundamental cellular processes. Although G-protein coupled receptor-mediated integrin activation has been extensively studied in non-adherent migratory cells such as leukocytes and platelets, much less is known about the regulation and functional impact of integrin activation in adherent stationary cells such as airway smooth muscle. Here we show that two different asthmagenic cytokines, IL-13 and IL-17A, activate type I and IL-17 cytokine receptor families respectively, to enhance adhesion of muscle to the matrix. These cytokines also induce activation of β1 integrins as detected by the conformation-specific antibody HUTS-4. Moreover, HUTS-4 binding is significantly increased in the smooth muscle of patients with asthma compared to healthy controls, suggesting a disease-relevant role for aberrant integrin activation. Indeed, we find integrin activation induced by a β1 activating antibody, the divalent cation manganese, or the synthetic peptide β1-CHAMP, dramatically enhances force transmission in collagen gels, mouse tracheal rings, and human bronchial rings even in the absence of cytokines. We further demonstrate that cytokine-induced activation of β1 integrins is regulated by a common pathway of NF-κB-mediated induction of RhoA and its effector Rho kinase, which in turn stimulates PIP5K1γ-mediated synthesis of PIP2 resulting in β1 integrin activation. Taken together, these data identify a previously unknown pathway by which type I and IL-17 cytokine receptor family stimulation induces functionally relevant β1 integrin activation in adherent smooth muscle and help explain the exaggerated force transmission that characterizes chronic airways diseases such as asthma.

FDA-Approved Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) Inhibitors for Managing Rheumatoid Arthritis: A Narrative Review of the Literature

Rheumatoid arthritis (RA) is a complex autoimmune disease causing chronic joint inflammation and, in more serious cases, organ involvement. RA typically affects people between the ages of 35 and 60; however, it can also afflict children younger than the age of 16 years and can also demonstrate a pattern of remission later in the disease course. Non-steroidal anti-inflammatory drugs, glucocorticoids, exercise, and patient education are all used in the management of RA, which is divided into symptomatic management and disease-modifying management (disease-modifying antirheumatic drugs) to reduce pain and inflammation, thereby preserving joint function. Janus kinase inhibitors (JAKis) have led to a substantial improvement in the management of RA. By specifically targeting the JAK-signal transducer and activator of transcription pathway, which is essential for immunological modulation, these inhibitors also demonstrate promise in treating various autoimmune illnesses, including inflammatory bowel diseases, giant cell arteritis, ankylosing spondylitis, and psoriatic arthritis. Tofacitinib, baricitinib, upadacitinib, peficitinib, delgocitinib, and filgotinib are examples of FDA-approved JAKis that have distinct properties and indications for treating a range of autoimmune illnesses. JAKis demonstrate a promising treatment approach for managing RA and other autoimmune diseases while enhancing patient outcomes and quality of life. However, due to major safety concerns and the need for long-term success, meticulous patient monitoring is essential.

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

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

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

Designing inhaled small molecule drugs for severe respiratory diseases: an overview of the challenges and opportunities

INTRODUCTION

Inhaled drugs offer advantages for the treatment of respiratory diseases over oral drugs by delivering the drug directly to the lung, thus improving the therapeutic index. There is an unmet medical need for novel therapies for lung diseases, exacerbated by a multitude of challenges for the design of inhaled small molecule drugs.

AREAS COVERED

The authors review the challenges and opportunities for the design of inhaled drugs for respiratory diseases with a focus on new target discovery, medicinal chemistry, and pharmacokinetic, pharmacodynamic, and toxicological evaluation of drug candidates.

EXPERT OPINION

Inhaled drug discovery is facing multiple unique challenges. Novel biological targets are scarce, as is the guidance for medicinal chemistry teams to design compounds with inhalation-compatible features. It is exceedingly difficult to establish a PK/PD relationship given the complexity of pulmonary PK and the impact of physical properties of the drug substance on PK. PK, PD and toxicology studies are technically challenging and require large amounts of drug substance. Despite the current challenges, the authors foresee that the design of inhaled drugs will be facilitated in the future by our increasing understanding of pathobiology, emerging medicinal chemistry guidelines, advances in drug formulation, PBPK models, and in vitro toxicology assays.

Early Atf4 activity drives airway club and goblet cell differentiation

Activating transcription factor 4 (Atf4), which is modulated by the protein kinase RNA-like ER kinase (PERK), is a stress-induced transcription factor responsible for controlling the expression of a wide range of adaptive genes, enabling cells to withstand stressful conditions. However, the impact of the Atf4 signaling pathway on airway regeneration remains poorly understood. In this study, we used mouse airway epithelial cell culture models to investigate the role of PERK/Atf4 in respiratory tract differentiation. Through pharmacological inhibition and silencing of ATF4, we uncovered the crucial involvement of PERK/Atf4 in the differentiation of basal stem cells, leading to a reduction in the number of secretory cells. ChIP-seq analysis revealed direct binding of ATF4 to regulatory elements of genes associated with osteoblast differentiation and secretory cell function. Our findings provide valuable insights into the role of ATF4 in airway epithelial differentiation and its potential involvement in innate immune responses and cellular adaptation to stress.

mTOR signaling regulates aberrant epithelial cell proliferative and migratory behaviors characteristic of airway mucous metaplasia in asthma

In asthma, the airway epithelium is hyperplastic, hypertrophied, and lined with numerous large MUC5AC-containing goblet cells (GC). Furthermore, the normal epithelial architecture is disorganized with numerous, what we here describe as, ectopic goblet cells (eGC) deep within the thickened epithelial layer disconnected from the lumenal surface. mTOR is a highly conserved pathway that regulates cell size and proliferation. We hypothesized that the balance between mTOR and autophagy signaling regulates key features of the asthma epithelial layer. Airway histological sections from subjects with asthma had increased frequency of eGC and increased levels of mTOR phosphorylation target-Ribosomal S6. Using human airway epithelial cells (hAECs) with IL-13 stimulation and timed withdrawal to stimulate resolution, we found that multiple key downstream phosphorylation targets downstream from the mTOR complex were increased during early IL-13-mediated mucous metaplasia, and then significantly declined during resolution. The IL-13-mediated changes in mTOR signaling were paralleled by morphologic changes with airway epithelial hypertrophy, hyperplasia, and frequency of eGC. We then examined the relationship between mTOR and autophagy using mice deficient in autophagy protein Atg16L1. Despite having increased cytoplasmic mucins, mouse AECs from Atg16L1 deficient mice had no significant difference in mTOR downstream signaling. mTOR inhibition with rapamycin led to a loss of IL-13-mediated epithelial hypertrophy, hyperplasia, ectopic GC distribution, and reduction in cytoplasmic MUC5AC levels. mTOR inhibition was also associated with a reduction in aberrant IL-13-mediated hAEC proliferation and migration. Our findings demonstrate that mTOR signaling is associated with mucous metaplasia and is crucial to the disorganized airway epithelial structure and function characteristic of muco-obstructive airway diseases such as asthma.

Graphical Abstract Key Concepts

The airway epithelium in asthma is disorganized and characterized by cellular proliferation, aberrant migration, and goblet cell mucous metaplasia.mTOR signaling is a dynamic process during IL-13-mediated mucous metaplasia, increasing with IL-13 stimulation and declining during resolution.mTOR signaling is strongly increased in the asthmatic airway epithelium.mTOR signaling is associated with the development of key features of the metaplastic airway epithelium including cell proliferation and ectopic distribution of goblet cells and aberrant cellular migration.Inhibition of mTOR leads to decreased epithelial hypertrophy, reduced ectopic goblet cells, and cellular migration.

The Importance of Th2 Immune Responses in Mediating the Progression of Gastritis-Associated Metaplasia to Gastric Cancer

Gastric cancer is one of the leading causes of cancer deaths worldwide, with chronic gastritis representing the main predisposing factor initiating the cascade of events leading to metaplasia and eventually progressing to cancer. A widely accepted classification distinguishes between autoimmune and environmental atrophic gastritis, mediated, respectively, by T cells promoting the destruction of the oxyntic mucosa, and chronic H. pylori infection, which has also been identified as the major risk factor for gastric cancer. The original dogma posits Th1 immunity as a main causal factor for developing gastritis and metaplasia. Recently, however, it has become evident that Th2 immune responses play a major role in the events causing chronic inflammation leading to tumorigenesis, and in this context, many different cell types and cytokines are involved. In particular, the activity of cytokines, such as IL-33 and IL-13, and cell types, such as mast cells, M2 macrophages and eosinophils, are intertwined in the process, promoting chronic gastritis-dependent and more diffuse metaplasia. Herein, we provide an overview of the critical events driving the pathology of this disease, focusing on the most recent findings regarding the importance of Th2 immunity in gastritis and gastric metaplasia.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN AND METHODS

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

RESULTS AND DISCUSSION

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

CONCLUSION

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

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

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

Interleukin 31 receptor α promotes smooth muscle cell contraction and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Multiple cytokines, including IFNγ, IL-4, and IL-13 are associated with asthma; however, the mechanisms underlying the effects of these cytokines remain unclear. Here, we report a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31, in mouse models of allergic asthma. In support of this, IFNγ, IL-4, and IL-13 upregulated IL-31RA but not IL-31 in both human and mice primary airway smooth muscle cells (ASMC) isolated from the airways of murine and human lungs. Importantly, the loss of IL-31RA attenuated AHR but had no effect on inflammation and goblet cell hyperplasia in mice challenged with allergens or treated with IL-13 or IFNγ. We show that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression, augmenting calcium levels and myosin light chain phosphorylation in human and murine ASMC. These findings identify a role for IL-31RA in AHR that is distinct from airway inflammation and goblet cell hyperplasia in asthma.

Therapeutic Targets and Precision Medicine in COPD: Inflammation, Ion Channels, Both, or Neither?

The development of a wider range of therapeutic options is a key objective in drug discovery for chronic obstructive pulmonary disease (COPD). Fundamental advances in lung biology have the potential to greatly expand the number of therapeutic targets in COPD. The recently reported successful Phase 3 clinical trial of the first biologic agent for COPD, the monoclonal antibody dupilumab, adds additional support to the importance of targeting inflammatory pathways in COPD. However, numerous other cellular mechanisms are important targets in COPD therapeutics, including airway remodeling, the CFTR ion channel, and mucociliary function. Some of these emerging targets can be exploited by the expanded use of existing COPD drugs, such as roflumilast, while targeting others will require the development of novel molecular entities. The identification of additional therapeutic targets and agents has the potential to greatly expand the value of using clinical and biomarker data to classify COPD into specific subsets, each of which can be predictive of an enhanced response to specific subset(s) of targeted therapies. The author reviews established and emerging drug targets in COPD and uses this as a framework to define a novel classification of COPD based on therapeutic targets. This novel classification has the potential to enhance precision medicine in COPD patient care and to accelerate clinical trials and pre-clinical drug discovery efforts.

GPR120/FFAR4 stimulation attenuates airway remodeling and suppresses IL-4- and IL-13-induced airway epithelial injury via inhibition of STAT6 and Akt

BACKGROUND

Airway remodeling is associated with severity and treatment insensitivity in asthma. This study aimed to investigate the effects of G protein-coupled receptor 120 (GPR120) stimulation on alleviating allergic inflammation and remodeling of airway epithelium.

RESEARCH DESIGN AND METHODS

Ovalbumin (OVA)-challenged BALB/c mice and type-2-cytokine (IL-4 and IL-13)-exposed 16HBE human bronchial epithelial cells were treated with GSK137647A, a selective GPR120 agonist. Markers of allergic inflammation and airway remodeling were determined.

RESULTS

GSK137647A attenuated inflammation and mucus secretion in airway epithelium of OVA-challenged mice. Stimulation of GPR120 in 16HBE suppressed expression of asthma-associated cytokines and cytokine-induced expression of pathogenic mucin-MUC5AC. These effects were abolished by co-treatment with AH7614, a GPR120 antagonist. Moreover, GPR120 stimulation in 16HBE cells reduced expression of fibrotic markers including fibronectin protein and ACTA2 mRNA and inhibited epithelial barrier leakage induced by type-2 inflammation via rescuing expression of zonula occludens-1 protein. Furthermore, GPR120 stimulation prevented the cytokine-induced airway epithelial remodeling via suppression of STAT6 and Akt phosphorylation.

CONCLUSIONS

Our findings suggest that GPR120 activation alleviates allergic inflammation and remodeling of airway epithelium partly through inhibition of STAT6 and Akt. GPR120 may represent a novel therapeutic target for diseases associated with remodeling of airway epithelium, including asthma.

A unique role for IL-13 in inducing esophageal eosinophilia through MID-1 and STAT6

Introduction

Eosinophilic esophagitis (EoE) is associated with allergen-driven inflammation of the esophagus and an upregulated Th2 cytokine signature. Recombinant interleukin (IL)-13 (rIL-13) administration to mice induces some of the hallmark features of EoE, including increased eotaxin expression and eosinophil recruitment. Inflammation in EoE has previously been shown to depend on the expression of TRAIL and MID-1, which reduced protein phosphatase 2A (PP2A) activity. The relationship between IL-13 and TRAIL signalling in esophageal eosinophilia is currently unknown.

Objective

To investigate the interaction between IL-13-driven eosinophil infiltration and TRAIL or MID-1 in the esophagus.

Method

We administered rIL-13 to wild type (WT), TRAIL-deficient (Tnsf10-/-) or STAT6-deficient (STAT6-/-) mice and targeted MID-1 with small interfering RNA.

Results

rIL-13 administration to mice increased TRAIL and MID-1 expression in the esophagus while reducing PP2A activity. TRAIL deficient, but not STAT6 deficient mice demonstrated increased MID-1 expression and PP2A reduction upon IL-13 challenge which correlated with eosinophil infiltration into the esophagus. Silencing MID-1 expression with siRNA completely ablated IL-13 induced eosinophil infiltration of the esophagus, restored PP2A activity, and reduced eotaxin-1 expression.

Conclusion

IL-13-driven eosinophil infiltration of the esophagus induced eosinophilia and eotaxin-1 expression in a STAT6-dependent and MID-1-dependent manner. This study highlights a novel mechanism employed by IL-13 to perpetuate eosinophil infiltration.

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

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

Eosinophil trafficking in allergen-mediated pulmonary inflammation relies on IL-13-driven CCL-11 and CCL-24 production by tissue fibroblasts and myeloid cells

Background

The immunologic mechanisms underlying pulmonary type 2 inflammation, including the dynamics of eosinophil recruitment to the lungs, still need to be elucidated.

Objective

We sought to investigate how IL-13-producing TH2 effector cells trigger eosinophil migration in house dust mite (HDM)-driven allergic pulmonary inflammation.

Methods

Multiparameter and molecular profiling of murine lungs with HDM-induced allergy was investigated in the absence of IL-13 signaling by using IL-13Rα1-deficient mice and separately through adoptive transfer of CD4+ T cells from IL-5-deficient mice into TCRα-/- mice before allergic inflammation.

Results

We demonstrated through single-cell techniques that HDM-driven pulmonary inflammation displays a profile characterized by TH2 effector cell-induced IL-13-dominated eosinophilic inflammation. Using HDM-sensitized IL-13Rα1-/- mice, we found a marked reduction in the influx of eosinophils into the lungs along with a significant downregulation of both CCL-11 and CCL-24. We further found that eosinophil trafficking to the lung relies on production of IL-13-driven CCL-11 and CCL-24 by fibroblasts and Ly6C+ (so-called classical) monocytes. Moreover, this IL-13-mediated eotaxin-dependent eosinophil influx to the lung tissue required IL-5-induced eosinophilia. Finally, we demonstrated that this IL-13-driven eosinophil-dominated pulmonary inflammation was critical for limiting bystander lung transiting Ascaris parasites in a model of allergy and helminth interaction.

Conclusion

Our data suggest that IL-5-dependent allergen-specific TH2 effector cell response and subsequent signaling through the IL-13/IL-13Rα1 axis in fibroblasts and myeloid cells regulate the eotaxin-dependent recruitment of eosinophils to the lungs, with multiple downstream consequences, including bystander control of lung transiting parasitic helminths.

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

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

Gene-Smoking Interaction Analysis for the Identification of Novel Asthma-Associated Genetic Factors

Asthma is a complex heterogeneous disease caused by gene-environment interactions. Although numerous genome-wide association studies have been conducted, these interactions have not been systemically investigated. We sought to identify genetic factors associated with the asthma phenotype in 66,857 subjects from the Health Examination Study, Cardiovascular Disease Association Study, and Korea Association Resource Study cohorts. We investigated asthma-associated gene-environment (smoking status) interactions at the level of single nucleotide polymorphisms, genes, and gene sets. We identified two potentially novel (SETDB1 and ZNF8) and five previously reported (DM4C, DOCK8, MMP20, MYL7, and ADCY9) genes associated with increased asthma risk. Numerous gene ontology processes, including regulation of T cell differentiation in the thymus (GO:0033081), were significantly enriched for asthma risk. Functional annotation analysis confirmed the causal relationship between five genes (two potentially novel and three previously reported genes) and asthma through genome-wide functional prediction scores (combined annotation-dependent depletion, deleterious annotation of genetic variants using neural networks, and RegulomeDB). Our findings elucidate the genetic architecture of asthma and improve the understanding of its biological mechanisms. However, further studies are necessary for developing preventive treatments based on environmental factors and understanding the immune system mechanisms that contribute to the etiology of asthma.

Protective effects of aloin on asthmatic mice by activating Nrf2/HO-1 pathway and inhibiting TGF-β/Smad2/3 pathway

BACKGROUND

Asthma is a severe chronic respiratory disease affecting all age groups with increasing prevalence. Anti-inflammatory strategies are promising options for the treatment of asthma. Although the inhibitory effect of aloin on inflammation has been demonstrated in various diseases, its effect on asthma remains unknown.

METHODS

A mice asthma model was established by treating with ovalbumin (OVA). The effects and mechanism of aloin on the OVA-treated mice were determined by enzyme-linked--immunosorbent serologic assay, biochemical examination, hematoxylin and eosin and Masson's staining, and Western blot assay.

RESULTS

OVA treatment in mice significantly increased the number of total cells, neutrophils, eosinophils, and macrophages and the concentration of interleukin (IL)-4, IL-5, and IL-13, which were attenuated with the administration of aloin. The content of malondialdehyde was enhanced in OVA-treated mice, with the decreased levels of superoxide dismutase and glutathione, which were reversed with aloin treatment. Aloin treatment reduced the airway resistance of OVA-induced mice. The inflammatory cell infiltration around small airways was accompanied by the thickening and contraction of bronchial walls and pulmonary collagen deposition in OVA-treated mice; however, these conditions were ameliorated with aloin treatment. Mechanically, aloin upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase 1 (HO-1) pathway but inhibited the level of transforming growth factor beta-SMAD2/3 genes (TGF-β/Smad2/3) axis in OVA-induced mice.

CONCLUSION

Aloin treatment lessened airway hyperresponsiveness, airway remodeling, inflammation, and oxidative stress in OVA-treated mice, and was closely related to the activation of Nrf2/HO-1 pathway and the weakening of TGF-β/Smad2/3 pathway.

TMT-based quantitative proteomics revealed protective efficacy of Icariside II against airway inflammation and remodeling via inhibiting LAMP2, CTSD and CTSS expression in OVA-induced chronic asthma mice

BACKGROUND

Asthma is a chronic inflammatory disorder in airways with typical pathologic features of airflow limitation, airway inflammation and remodeling. Icariside II (IS), derived from herbal medicine Herba Epimedii, exerts an anti-inflammatory property. However, underlying mechanisms with specifically targeted molecular expression by IS in asthma have not been fully understood, and whether IS could inhibit remodeling and EMT still remains unclear.

PURPOSE

The study aimed to clarify therapeutic efficacy of IS for attenuating airway inflammation and remodeling in asthma, and illustrate IS-regulated specific pathway and target proteins through TMT-based quantitative proteomics.

STUDY DESIGN AND METHODS

Murine model of chronic asthma was constructed with ovalbumin (OVA) sensitization and then challenge for 8 weeks. Pulmonary function, leukocyte count in bronchoalveolar lavage fluid (BALF), lung histopathology, inflammatory and fibrotic cytokines, and markers of epithelial-mesenchymal transition (EMT) were evaluated. TMT-based quantitative proteomics were performed on lung tissues to explore IS-regulated proteins.

RESULTS

IS contributed to alleviative airway hyperresponsiveness (AHR) evidenced by declined R_L and increased Cdyn. After IS treatment, we observed a remarked down-regulation of leukocyte count, inflammatory cytokines in BALF, and peribronchial inflammation infiltration. Goblet cell hyperplasia, mucus secretion and peribronchial collagen deposition were attenuated, with the level of TGF-β and MMP-9 in BALF declined. Furthermore, IS induced a rise of Occludin and E-cadherin and a decline of N-cadherin and α-SMA in lung tissues. These results proved the protective property of IS against airway inflammation, remodeling and EMT. To further investigate underlying mechanisms of IS in asthma treatment, TMT-based quantitative proteomics were performed and 102 overlapped DEPs regulated by IS were identified. KEGG enrichment exhibited these DEPs were enriched in lysosome, phagosome and autophagy, in which LAMP2, CTSD and CTSS were common DEPs. WB, q-PCR and IHC results proofed expressional alteration of these proteins. Besides, IS could decrease Beclin-1 and LC3B expression with increasing p62 expression thus inhibiting autophagy.

CONCLUSIONS

The study demonstrated IS could ameliorate AHR, airway inflammation, remodeling and EMT in OVA-induced chronic asthma mice. Our research was the first to reveal that inhibition of LAMP2, CTSD and CTSS expression in autophagy contributed to the therapeutic efficacy of IS to asthma.

Chronic airway epithelial hypoxia exacerbates injury in muco-obstructive lung disease through mucus hyperconcentration

Unlike solid organs, human airway epithelia derive their oxygen from inspired air rather than the vasculature. Many pulmonary diseases are associated with intraluminal airway obstruction caused by aspirated foreign bodies, virus infection, tumors, or mucus plugs intrinsic to airway disease, including cystic fibrosis (CF). Consistent with requirements for luminal O2, airway epithelia surrounding mucus plugs in chronic obstructive pulmonary disease (COPD) lungs are hypoxic. Despite these observations, the effects of chronic hypoxia (CH) on airway epithelial host defense functions relevant to pulmonary disease have not been investigated. Molecular characterization of resected human lungs from individuals with a spectrum of muco-obstructive lung diseases (MOLDs) or COVID-19 identified molecular features of chronic hypoxia, including increased EGLN3 expression, in epithelia lining mucus-obstructed airways. In vitro experiments using cultured chronically hypoxic airway epithelia revealed conversion to a glycolytic metabolic state with maintenance of cellular architecture. Chronically hypoxic airway epithelia unexpectedly exhibited increased MUC5B mucin production and increased transepithelial Na+ and fluid absorption mediated by HIF1α/HIF2α-dependent up-regulation of β and γENaC (epithelial Na+ channel) subunit expression. The combination of increased Na+ absorption and MUC5B production generated hyperconcentrated mucus predicted to perpetuate obstruction. Single-cell and bulk RNA sequencing analyses of chronically hypoxic cultured airway epithelia revealed transcriptional changes involved in airway wall remodeling, destruction, and angiogenesis. These results were confirmed by RNA-in situ hybridization studies of lungs from individuals with MOLD. Our data suggest that chronic airway epithelial hypoxia may be central to the pathogenesis of persistent mucus accumulation in MOLDs and associated airway wall damage.