IL-13 induces mucin production by stimulating epidermal growth factor receptors and by activating neutrophils

Emerging cell and molecular targets for treating mucus hypersecretion in asthma

Mucus provides a protective barrier that is crucial for host defense in the lungs. However, excessive or abnormal mucus can have pathophysiological consequences in many pulmonary diseases, including asthma. Patients with asthma are treated with agents that relax airway smooth muscle and reduce airway inflammation, but responses are often inadequate. In part, this is due to the inability of existing therapeutic agents to directly target mucus. Accordingly, there is a critical need to better understand how mucus hypersecretion and airway plugging are affected by the epithelial cells that synthesize, secrete, and transport mucus components. This review highlights recent advances in the biology of mucin glycoproteins with a specific focus on MUC5AC and MUC5B, the chief macromolecular components of airway mucus. An improved mechanistic understanding of key steps in mucin production and secretion will help reveal novel potential therapeutic strategies.

Mucus Structure, Viscoelastic Properties, and Composition in Chronic Respiratory Diseases

The respiratory mucus, a viscoelastic gel, effectuates a primary line of the airway defense when operated by the mucociliary clearance. In chronic respiratory diseases (CRDs), such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF), the mucus is overproduced and its solid content augments, changing its structure and viscoelastic properties and determining a derangement of essential defense mechanisms against opportunistic microbial (virus and bacteria) pathogens. This ensues in damaging of the airways, leading to a vicious cycle of obstruction and infection responsible for the harsh clinical evolution of these CRDs. Here, we review the essential features of normal and pathological mucus (i.e., sputum in CF, COPD, and asthma), i.e., mucin content, structure (mesh size), micro/macro-rheology, pH, and osmotic pressure, ending with the awareness that sputum biomarkers (mucins, inflammatory proteins and peptides, and metabolites) might serve to indicate acute exacerbation and response to therapies. There are some indications that old and novel treatments may change the structure, viscoelastic properties, and biomarker content of sputum; however, a wealth of work is still needed to embrace these measures as correlates of disease severity in association with (or even as substitutes of) pulmonary functional tests.

Allergy in pathogenesis of Eustachian Tube Dysfunction

Eustachian tube dysfunction (ETD) is a condition where the Eustachian tube (ET) fails to function normally, resulting in symptoms such as aural fullness, tinnitus, autophony, and hearing loss. ETD can further lead to middle ear diseases such as otitis media effusion and adhesive otitis media, which is becoming more common in the field of otology. Although the pathogenesis of ETD remains unclear, recent animal studies and clinical experiments have found allergic reactions and allergic diseases are closely related to the occurrence of ETD. As the mucosa of the ET is continuous with that of the nasopharynx and tympanic cavity, it is reasonable to assume that the immunological basis of the ET itself is similar to that of respiratory allergic diseases. However, due to the special anatomical location and complex pathogenesis of the ET, there is still no unified diagnostic gold standard. Additionally, there is an ongoing debate regarding whether ETD can be classified as a distinct disease or even an allergic disease. Furthermore, the effectiveness of anti-allergic therapy in patients with ETD is yet to be fully understood. Therefore, this review elaborates on the possible mechanisms of allergic reactions in the occurrence and development of ETD, and explores the potential role of anti-allergic therapy in managing this condition, in order to provide new insights into the pathogenesis and prevention of ETD.

Solithromycin inhibits IL-13-induced goblet cell hyperplasia and MUC5AC, CLCA1, and ANO1 in human bronchial epithelial cells

Solithromycin is a novel fluoroketolide antibiotic belonging to the class of macrolide antibiotics. Activation of the interleukin (IL)-13 receptor leads to STAT6 activation and subsequent induction of SAM pointed domain containing ETS transcription factor (SPDEF), chloride channel accessory 1 (CLCA1), and anoctamin-1 (ANO1), all of which are associated with the induction of MUC5AC. We examined the effects of solithromycin on mucin production led by IL-13 signaling. Normal human bronchial epithelial cells were grown at the air-liquid interface with IL-13 with/without solithromycin for 14 days. Histochemical analysis was performed using hematoxylin and eosin staining and MUC5AC immunostaining. MUC5AC, SPDEF, CLCA1, and ANO1 mRNA expressions were examined using real-time polymerase chain reaction. Western blot analysis was performed to assess CLCA1 and ANO1 proteins, and phosphorylation of STAT6 and ERK. Solithromycin attenuated IL-13 induction of goblet cell hyperplasia and MUC5AC, CLCA1 and ANO1 mRNA and protein expression induced by IL-13, but had no effect on the phosphorylation of STAT6 and ERK. Our results indicate that solithromycin could attenuate goblet cell hyperplasia and MUC5AC induced by IL-13 through inhibition of CLCA1 and ANO1 mRNA and protein expression. However, much more information is required to clarify the molecular mechanisms underlying the inhibition of CLCA1 and ANO1 by solithromycin.

How an Immune-Factor-Based Formulation of Micro-Immunotherapy Could Interfere with the Physiological Processes Involved in the Atopic March

Allergic diseases consist of improper inflammatory reactions to antigens and are currently an important healthcare concern, especially considering their increasing worldwide development in recent decades. The "atopic march" defines the paradigm of allergic diseases occurring in chronological order and displaying specific spatial manifestations, as they usually start as atopic dermatitis (AD) and food allergies during infancy and progressively evolve into allergic asthma (AA) and allergic rhinitis (AR) or rhino-conjunctivitis in childhood. Many immune cell subtypes and inflammatory factors are involved in these hypersensitivity reactions. In particular, the T helpers 2 (Th2) subset, through its cytokine signatures made of interleukins (ILs), such as IL-4, IL-5, IL-10, and IL-13, as well as mast cells and their related histamine pathways, contribute greatly to the perpetuation and evolution of the atopic march. By providing low doses (LD) and ultra-low doses (ULD) of ILs and immune factors to the body, micro-immunotherapy (MI) constitutes an interesting therapeutic strategy for the management of the atopic march and its symptoms. One of the aims of this review is to shed light on the current concept of the atopic march and the underlying immune reactions occurring during the IgE-mediated responses. Moreover, the different classes of traditional and innovative treatments employed in allergic diseases will also be discussed, with a special emphasis on the potential benefits of the MI medicine 2LALERG^® formulation in this context.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

Nonylphenol exacerbates ovalbumin-induced allergic rhinitis via the TSLP-TSLPR/IL-7R pathway and JAK1/2-STAT3 signaling in a mouse model

Nonylphenol (NP) can be widely used as a plasticizer, surfactant, antioxidant, textile printing, dyeing additive, and pesticide emulsifier. Animal studies have shown that NP aggravates ovalbumin (OVA)-induced allergic rhinitis (AR); however, the exact mechanism underlying its action has not yet been detailed. This study aimed to explore the aggravation of the AR inflammatory response following NP exposure and its possible mechanism. The AR mouse model was constructed using OVA. Under NP exposure, allergic nasal symptoms were observed, eosinophil infiltration was assessed by Sirius red staining, and the levels of IL-4, IL-5, and IL-13 in nasal mucosa samples were detected using cytometric bead array. The mRNA levels of OX40/OX40L and GATA3 in nasal mucosa were detected by qPCR, and the expression levels of the TSLP and JAK1/2-STAT3 signaling pathway components were also identified. Our results suggest that NP exposure exacerbated allergic nasal symptoms and that eosinophils accumulated in nasal mucosa after OVA challenge. The levels of the typical T helper 2 cytokines, as well as the mRNA levels of OX40/OX40L and GATA3, were elevated in the nasal mucosa of OVA-challenged mice exposed to NP. In addition, NP exposure elevated the TSLP, TSLPR, IL-7R, p-JAK1, p-JAK2, and p-STAT3 levels in the nasal mucosa after OVA stimulation. Overall, the present study suggests NP can exacerbate OVA-induced AR inflammatory responses; furthermore, this aggravating effect of NP may be related to the TSLP-TSLPR/IL-7R and JAK1/2-STAT3 signaling pathways.

Pulmonary toxicity in driver gene positive non-small cell lung cancer therapy

Molecular targeted therapy significantly improved the therapeutic efficacy in non-small cell lung cancer (NSCLC) patients with driver gene mutations but also with new toxicity profiles. Although most patients treated with these drugs developed relatively controllable toxicity, significant pulmonary toxicity events, including interstitial lung disease, occurred in a small proportion of patients and can lead to discontinuation or even be life-threatening. Pulmonary toxicity associated with these anti-tumor drugs is a problem that cannot be ignored in clinical practice. The prompt diagnosis of drug-related lung injury and the consequent differential diagnosis with other forms of pulmonary disease are critical in the management of pulmonary toxicity. Current knowledge of the pathophysiology and management of pulmonary toxicity associated with these targeted drugs is limited, and participants should be able to identify and respond to the development of drug-induced pulmonary toxicity. This review offers information about the potential pathogenesis, risk factors and management for the development of these events based on the available literature. This review focused on pulmonary toxicities in driver gene-positive NSCLC therapy by describing the related adverse events to promote the awareness and management of this important toxicity related to antitumor-targeted therapy.

Bisphenol A attenuates the therapeutic effect of the selective G protein-coupled estrogen receptor agonist G-1 on allergic rhinitis inflammation in mice

BACKGROUND

Bisphenol A (BPA) is found in many plastics widely used in everyday life and affects the immune system. Previous studies found that the selective G protein coupled estrogen receptor (GPER) agonist G-1 can reduce the inflammation associated with asthma and allergic rhinitis (AR). BPA also interferes with the protective effect of estradiol against myocardial ischemia-reperfusion injury.

OBJECTIVE

We explored whether BPA attenuates the effect of G-1 on inflammation in a mouse AR model.

METHODS

The AR model was established by sensitizing and stimulating female BALB/c mice with ovalbumin (OVA) and G-1/BPA. Eosinophils, neutrophils, and lymphocyte subsets (including T and B cells) in nasal mucosa and Th2 and Treg cells in the spleen were detected by flow cytometry. Cytokines and transcription factors characteristic of Th2 and Treg cells in nasal mucosa were detected using cytometric bead arrays and quantitative PCR, respectively.

RESULTS

G-1 reduced OVA-induced nasal mucosal inflammation in mice. The proportions of eosinophils, neutrophils, Siglec-F⁺ neutrophils, lymphocytes, and T cell subsets were reduced by G-1, and this effect was attenuated by BPA. G-1 significantly decreased the Th2 population and levels of IL-4, IL-5, IL-13 and GATA-3; these effects were attenuated by BPA. The enhanced Treg response (as evidenced by an increased Treg population and higher IL-10 and Foxp3 levels) mediated by G-1 tended to be reduced by BPA.

DISCUSSION

We found that G-1 reduced OVA-induced nasal mucosal inflammation and significantly decreased the Th2 response, while increasing the Treg response. These effects were attenuated by BPA.

Chronic Inflammation as the Underlying Mechanism of the Development of Lung Diseases in Psoriasis: A Systematic Review

Psoriasis is a systemic inflammatory disease caused by dysfunctional interactions between the innate and adaptive immune responses. The systemic inflammation in psoriasis may be associated with the development of comorbidities, including lung diseases. In this review, we aimed to provide a summary of the evidence regarding the prevalence of lung diseases in patients with psoriasis and the potential underlying mechanisms. Twenty-three articles published between March 2010 and June 2021 were selected from 195 initially identified records. The findings are discussed in terms of the prevalence of asthma, chronic obstructive pulmonary disease, interstitial lung disease, obstructive sleep apnea, pulmonary hypertension, and sarcoidosis in psoriasis. A higher prevalence of lung diseases in psoriasis has been confirmed in asthma, chronic obstructive pulmonary disease, obstructive sleep apnea, and pulmonary hypertension. These conditions are important as they are previously unrecognized causes of morbidity and mortality in psoriasis. The development of lung diseases in patients with psoriasis can be explained by several mechanisms, including common risk factors, shared immune and molecular characteristics associated with chronic inflammation, as well as other mechanisms. Understanding the prevalence of lung diseases in psoriasis and their underlying mechanisms can help implement appropriate preventative and therapeutic strategies to address respiratory diseases in patients with psoriasis.

TGF-β1 Drives Inflammatory Th Cell But Not Treg Cell Compartment Upon Allergen Exposure

TGF-β1 is known to have a pro-inflammatory impact by inducing Th9 and Th17 cells, while it also induces anti-inflammatory Treg cells (Tregs). In the context of allergic airway inflammation (AAI) its dual role can be of critical importance in influencing the outcome of the disease. Here we demonstrate that TGF-β is a major player in AAI by driving effector T cells, while Tregs differentiate independently. Induction of experimental AAI and airway hyperreactivity in a mouse model with inducible genetic ablation of the gene encoding for TGFβ-receptor 2 (Tgfbr2) on CD4⁺T cells significantly reduced the disease phenotype. Further, it blocked the induction of pro-inflammatory T cell frequencies (Th2, Th9, Th17), but increased Treg cells. To translate these findings into a human clinically relevant context, Th2, Th9 and Treg cells were quantified both locally in induced sputum and systemically in blood of allergic rhinitis and asthma patients with or without allergen-specific immunotherapy (AIT). Natural allergen exposure induced local and systemic Th2, Th9, and reduced Tregs cells, while therapeutic allergen exposure by AIT suppressed Th2 and Th9 cell frequencies along with TGF-β and IL-9 secretion. Altogether, these findings support that neutralization of TGF-β represents a viable therapeutic option in allergy and asthma, not posing the risk of immune dysregulation by impacting Tregs cells.

Characterization of the Immune Response to Vibrio cholerae Infection in a Natural Host Model

The gram-negative bacterium Vibrio cholerae causes the life-threatening diarrheal disease cholera, which is spread through the ingestion of contaminated food or water. Cholera epidemics occur largely in developing countries that lack proper infrastructure to treat sewage and provide clean water. Numerous vertebrate fish species have been found to be natural V. cholerae hosts. Based on these findings, zebrafish (Danio rerio) have been developed as a natural host model for V. cholerae. Diarrheal symptoms similar to those seen in humans are seen in zebrafish as early as 6 hours after exposure. Our understanding of basic zebrafish immunology is currently rudimentary, and no research has been done to date exploring the immune response of zebrafish to V. cholerae infection. In the present study, zebrafish were infected with either pandemic El Tor or non-pandemic, environmental V. cholerae strains and select immunological markers were assessed to determine cellular immunity and humoral immunity. Significant increases in the gene expression of two transcription factors, T-bet and GATA3, were observed in response to infection with both V. cholerae strains, as were levels of mucosal related antibodies. Additionally, the cytokine IL-13 was shown to be significantly elevated and paralleled the mucin output in zebrafish excretions, strengthening our knowledge of IL-13 induced mucin production in cholera. The data presented here further solidify the relevancy of the zebrafish model in studying V. cholerae, as well as expanding its utility in the field of cholera immunology.

Changes in Eustachian Tube Mucosa in Mice After Short-Term Tobacco and E-cigarette Smoke Exposure

OBJECTIVES

To evaluate histologic changes in middle ear and eustachian tube (ET) mucosa of mice after exposure to tobacco or electronic cigarette (e-cigarette) smoke. To determine whether there were any mitigating effects of middle ear application of anti-IL-13 or the epidermal growth factor receptor antagonist AG1478 on noted changes within ET mucosa.

STUDY DESIGN

Controlled animal study.

METHODS

Fifty BALB/cJ mice were randomly assigned to one of five groups: A control group with no smoke exposure, two groups exposed to tobacco smoke, and two groups exposed to e-cigarette vapor. Within the exposed groups after 4 weeks of exposure, one ear was infiltrated with a saline hydrogel and the other ear with hydrogel of either Anti-IL-13 or AG1478. After four more weeks of exposure, the animals were euthanized and the ETs were evaluated for mucosal changes.

RESULTS

Compared to control animals with no smoke exposure, there were significant decreases in the numbers of goblet cells within the ET mucosa of mice exposed to tobacco smoke and e-cigarette vapor. No significant differences in cilia, mucin, or squamous metaplasia were noted. Neither anti-IL-13 nor AG178 significantly altered goblet cell count in the ET mucosa of mice exposed to tobacco smoke; however, both agents significantly increased goblet cells within the ET mucosa of mice exposed to e-cigarette vapor.

CONCLUSION

Short-term tobacco smoke and e-cigarette vapor significantly decrease goblet cell count in mouse ET mucosa. Middle ear application of both anti-IL-13 and AG1478 resulted in an increase in goblet cell count among mice exposed to e-cigarette vapor, but not to tobacco smoke.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

Evaluating the Protective Properties of a Xyloglucan-Based Nasal Spray in a Mouse Model of Allergic Rhinitis

A breached nasal epithelial barrier plays an important role in driving allergic rhinitis (AR). Corticosteroids remain the standard of care (SoC) but come with side effects, thus alternative safe and effective treatments able to avoid inflammation and restore barrier integrity are needed. The aim of the present study is to evaluate the barrier-forming capacity of a xyloglucan-based nasal spray (XG) and compare its efficacy to several SoC treatments (corticosteroid spray, oral mast-cell stabilizer and oral antihistamine) in reducing allergic responses in addition to its effect when concomitantly administered with an antihistamine. An ovalbumin (OVA)-induced mouse AR model was used. XG shows a significant efficacy in reducing histological damage in AR mice; improves nasal rubbing and histamine-induced hyper-responsiveness. Total and OVA-specific IgE as well as pro-inflammatory cytokines are significantly reduced compared to OVA challenged-mice, with im-proved efficacy when used as an add-on treatment. However, XG reduces mucous secreting cells (PAS-positive) and mucin mRNA expression similar to the corticosteroid-treated mice. XG-spray maintains tight junction protein expression (ZO-1) and conversely decreases HDAC1 significantly; the latter being highly expressed in AR patients. Moreover, the concomitant treatment showed in all of the endpoints a similar efficacy to the corticosteroids. This innovative approach may represent a novel therapeutic strategy for nasal respiratory diseases like AR, reducing undesirable side effects and improving the quality of life in patients.

The Effects of Maternal Smoking on Pregnancy and Offspring: Possible Role for EGF?

Cigarette smoke exposure during pregnancy and lactation is associated with adverse pregnancy outcomes. Here, we investigated the effects of maternal smoke exposure on pregnancy and offspring immunity and explored whether, epidermal growth factor (EGF), an important growth-promoting factor in human colostrum and milk, might be a possible missing link in maternal smoke exposure and changes in infants’ immune responses. Pregnant BALB/c mice were exposed to either cigarette smoke or air during gestation and lactation, and effects on pulmonary inflammation in dams and immune responses in offspring were examined. Maternal smoke exposure increased airway hyperresponsiveness and accumulation of inflammatory cells in the lungs of pregnant dams compared to non-pregnant dams. The E-cadherin protein expression was reduced in mammary glands of cigarette smoke-exposed pregnant dams. EGF levels were higher in mammary glands and serum of smoke-exposed pregnant dams compared to air-exposed pregnant dams. Offspring from cigarette smoke-exposed dams exhibited elevated levels of IL-17A, MCP-1, IL-22, and IL-13 in anti-CD3 stimulated spleen cell culture supernatants. EGF levels were also increased in serum of offspring from smoke-exposed dams. A positive correlation was observed between serum EGF levels and neutrophil numbers in bronchoalveolar lavage fluid of the dams. Interestingly, IL-17A, MCP-1, IL-22, IL13, and IFN-γ levels in anti-CD3 stimulated spleen cell culture supernatants of male pups also showed a positive correlation with EGF serum levels. In summary, our results reveal that maternal smoke exposure predisposes dams to exacerbated airway inflammation and offspring to exacerbated immune responses and both phenomena are associated with elevated EGF concentrations.

Oxidant-induced epithelial alarmin pathway mediates lung inflammation and functional decline following ultrafine carbon and ozone inhalation co-exposure

Environmental inhalation exposures are inherently mixed (gases and particles), yet regulations are still based on single toxicant exposures. While the impacts of individual components of environmental pollution have received substantial attention, the impact of inhalation co-exposures is poorly understood. Here, we mechanistically investigated pulmonary inflammation and lung function decline after inhalation co-exposure and individual exposures to ozone (O₃) and ultrafine carbon black (CB). Environmentally/occupationally relevant lung deposition levels in mice were achieved after inhalation of stable aerosols with similar aerodynamic and mass median distributions. X-ray photoemission spectroscopy detected increased surface oxygen contents on particles in co-exposure aerosols. Compared with individual exposures, co-exposure aerosols produced greater acellular and cellular oxidants detected by electron paramagnetic resonance (EPR) spectroscopy, and in vivo immune-spin trapping (IST), as well as synergistically increased lavage neutrophils, lavage proteins and inflammation related gene/protein expression. Co-exposure induced a significantly greater respiratory function decline compared to individual exposure. A synthetic catalase-superoxide dismutase mimetic (EUK-134) significantly blunted lung inflammation and respiratory function decline confirming the role of oxidant imbalance. We identified a significant induction of epithelial alarmin (thymic stromal lymphopoietin-TSLP)-dependent interleukin-13 pathway after co-exposure, associated with increased mucin and interferon gene expression. We provided evidence of interactive outcomes after air pollution constituent co-exposure and identified a key mechanistic pathway that can potentially explain epidemiological observation of lung function decline after an acute peak of air pollution. Developing and studying the co-exposure scenario in a standardized and controlled fashion will enable a better mechanistic understanding of how environmental exposures result in adverse outcomes.

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Interaction with O₃ mediates free radical production on the surface of carbon black (CB) particles.

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Oxidants mediate co-exposure (CB + O₃)-induced lung function decline.

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EUK-134 (a synthetic superoxide-catalase mimetic) abrogates CB + O₃-induced lung inflammation.

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CB + O₃ co-exposure induces greater lung inflammation than individual exposures.

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Epithelial alarmin (TSLP) contributes significantly to the CB + O₃ toxicity.

Molecular and Clinical Features of EGFR-TKI-Associated Lung Injury

The tyrosine kinase activity of epidermal growth factor receptors (EGFRs) plays critical roles in cell proliferation, regeneration, tumorigenesis, and anticancer resistance. Non-small-cell lung cancer patients who responded to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) and obtained survival benefits had somatic EGFR mutations. EGFR-TKI-related adverse events (AEs) are usually tolerable and manageable, although serious AEs, including lung injury (specifically, interstitial lung disease (ILD), causing 58% of EGFR-TKI treatment-related deaths), occur infrequently. The etiopathogenesis of EGFR-TKI-induced ILD remains unknown. Risk factors, such as tobacco exposure, pre-existing lung fibrosis, chronic obstructive pulmonary disease, and poor performance status, indicate that lung inflammatory circumstances may worsen with EGFR-TKI treatment because of impaired epithelial healing of lung injuries. There is limited evidence from preclinical and clinical studies of the mechanisms underlying EGFR-TKI-induced ILD in the available literature. Herein, we evaluated the relationship between EGFR-TKIs and AEs, especially ILD. Recent reports on mechanisms inducing lung injury or resistance in cytokine-rich circumstances were reviewed. We discussed the relevance of cytotoxic agents or immunotherapeutic agents in combination with EGFR-TKIs as a potential mechanism of EGFR-TKI-related lung injury and reviewed recent developments in diagnostics and therapeutics that facilitate recovery from lung injury or overcoming resistance to anti-EGFR treatment.

Mucin mutations and aberrant expression are associated with the pathogenesis of immune thrombocytopenia

PURPOSE

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease of unknown aetiology. In this study, we aimed to identify the mutations and aberrant expression of mucins associated with ITP pathogenesis.

METHODS

First, we investigated the DNA mutation profile of bone marrow samples from patients with ITP (n = 20) by using next-generation sequencing (NGS). In addition, MUC3A, MUC5B and MUC6 were mutated in all patients with ITP. ELISA (enzyme-linked immunoassay) was used to measure MUC3A, MUC5B and MUC6 levels in the plasma of bone marrow fluid mononuclear cells (BMMCs) and peripheral blood mononuclear cells (PBMCs). Real-time quantitative PCR was used to study the mRNA expression levels of MUC3A, MUC5B and MUC6 in BMMCs and PBMCs.

RESULTS

The results indicated that there were 3998 missense mutations involving 2269 genes in more than 10 individuals. MUC3A levels were not significantly different among the three groups, whereas MUC5B and MUC6 expression were significantly down-regulated in patients with ITP compared with healthy controls. In addition, serum MUC5B and MUC6 levels were significantly higher in patients with ITP in clinical remission than in patients with active ITP.

CONCLUSIONS

Taken together, these results suggest that genetic alterations and the aberrant serum expression of mucins might be involved in the pathogenesis of ITP.

Bisphenol A Exacerbates Allergic Inflammation in an Ovalbumin-Induced Mouse Model of Allergic Rhinitis

Purpose

Bisphenol A (BPA) is found in many plastic products and is thus a common environmental endocrine disruptor. Plastic-related health problems, including allergic diseases, are attracting increasing attention. However, few experimental studies have explored the effect of BPA on allergic rhinitis (AR). We explore whether BPA was directly related to the allergic inflammation induced by ovalbumin (OVA) in AR mice.

Methods

We first constructed OVA-induced mouse model, and after BPA administration, we evaluated nasal symptoms and measured the serum OVA-specific IgE levels by ELISA. Th2 and Treg-related cytokines of nasal mucosa were measured by cytometric bead array. Th2 and Treg-specific transcription factor levels were assayed by PCR. The proportions of CD3⁺CD4⁺IL-4⁺Th2 and CD4⁺Helios⁺Foxp3⁺ T cells (Tregs) in spleen tissue were determined by flow cytometry.

Results

Compared to OVA-only-induced mice, BPA addition increased nasal symptoms and serum OVA-specific IgE levels. OVA and BPA coexposure significantly increased IL-4 and IL-13 protein levels compared to those after OVA exposure alone. BPA plus OVA tended to decrease the IL-10 protein levels compared to those after OVA alone. Coexposure to OVA and BPA significantly increased the GATA-3-encoding mRNA level, and decreased the levels of mRNAs encoding Foxp3 and Helios, compared to those after OVA exposure alone. BPA increased the Th2 cell proportion, and decreased that of Tregs, compared to the levels with OVA alone.

Conclusion

BPA exerted negative effects by exacerbating AR allergic symptoms, increasing serum OVA-specific IgE levels, and compromising Th2 and Treg responses.

Are We Meeting the Promise of Endotypes and Precision Medicine in Asthma?

While the term asthma has long been known to describe heterogeneous groupings of patients, only recently have data evolved which enable a molecular understanding of the clinical differences. The evolution of transcriptomics (and other 'omics platforms) and improved statistical analyses in combination with large clinical cohorts opened the door for molecular characterization of pathobiologic processes associated with a range of asthma patients. When linked with data from animal models and clinical trials of targeted biologic therapies, emerging distinctions arose between patients with and without elevations in type 2 immune and inflammatory pathways, leading to the confirmation of a broad categorization of type 2-Hi asthma. Differences in the ratios, sources, and location of type 2 cytokines and their relation to additional immune pathway activation appear to distinguish several different (sub)molecular phenotypes, and perhaps endotypes of type 2-Hi asthma, which respond differently to broad and targeted anti-inflammatory therapies. Asthma in the absence of type 2 inflammation is much less well defined, without clear biomarkers, but is generally linked with poor responses to corticosteroids. Integration of "big data" from large cohorts, over time, using machine learning approaches, combined with validation and iterative learning in animal (and human) model systems is needed to identify the biomarkers and tightly defined molecular phenotypes/endotypes required to fulfill the promise of precision medicine.

The Relation of Allergy to Eustachian Tube Dysfunction and the Subsequent Need for Insertion of Pressure Equalization Tubes

INTRODUCTION

The most basic question to be answered in each case in which the choice of using a pressure equalization tube (PET) is being considered is: "what is the underlying pathophysiology of the middle ear disease being addressed?"

METHODS

We will evaluate the hypothesis that the Eustachian Tube (ET) may become "dysfunctional" due to allergic mucosal edema and obstruction. We review the literature that evaluates the role of ET, the proposed affect that allergy may contribute to ET dysfunction (ETD), and the relation of allergic rhinitis to otitis.

RESULTS

Proof that allergy affects the middle ear was supported by (1) over a dozen investigators using objective immunotherapy demonstrating over the past 70 years that 72% to 100% of the children with otitis media with effusion (OME) are atopic, (2) an association of allergic Th2 immune-mediated histochemical reactivity within the target organ itself, (3) establishment that inflammation within the middle ear is truly allergic in nature, and (4) direct evidence of a dose-response curve and consistency of results, which confirm that OME resolves on allergy immunotherapy.

CONCLUSION

Current medical evidence should heighten the awareness of physicians of the physiology that underlies ETD. The evidence supports the link between allergy and OME. The middle ear behaves like the rest of the respiratory tract, and what has been learned about the atopic response in the sinuses and lungs may be applied to the study of the immunologic mechanisms within the middle ear that lead to ETD requiring the use of PET.

SMAD Signaling Restricts Mucous Cell Differentiation in Human Airway Epithelium

Mucin-secreting goblet cell metaplasia and hyperplasia (GCMH) is a common pathological phenotype in many human respiratory diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, primary ciliary dyskinesia, and infections. A better understanding of how goblet cell quantities or proportions in the airway epithelium are regulated may provide novel therapeutic targets to mitigate GCMH in these devastating diseases. We identify canonical SMAD signaling as the principal pathway restricting goblet cell differentiation in human airway epithelium. Differentiated goblet cells express low levels of phosphorylated SMAD. Accordingly, inhibition of SMAD signaling markedly amplifies GCMH induced by mucous mediators. In contrast, SMAD signaling activation impedes goblet cell generation and accelerates the resolution of preexisting GCMH. SMAD signaling inhibition can override the suppressive effects imposed by a GABAergic receptor inhibitor, suggesting the GABAergic pathway likely operates through inhibition of SMAD signaling in regulating mucous differentiation. Collectively, our data demonstrate that SMAD signaling plays a determining role in mucous cell differentiation, and thus raise the possibility that dysregulation of this pathway contributes to respiratory pathophysiology during airway inflammation and pulmonary diseases. In addition, our study also highlights the potential for SMAD modulation as a therapeutic target in mitigating GCMH.

Epidermal growth factor receptor (EGFR) involvement in epithelial-derived cancers and its current antibody-based immunotherapies

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein that is part of the family of tyrosine kinase receptors. The binding of EGFR to its cognate ligands leads to its autophosphorylation and subsequent activation of the signal transduction pathways involved in regulating cellular proliferation, differentiation, and survival. Accordingly, this receptor carries out both redundant and restricted functions in the germline development of mammals and in the maintenance of various adult tissues. Correspondingly, the loss of EGFR regulation results in many human diseases, with the most notable cancer. This receptor is overexpressed and/or mutated in multiple epithelial-derived tumors, and associated with poor prognosis and survival in cancer patients. Here, we discuss in detail the role of EGFR in specific epithelial-derived cancer pathologies; these include lung cancer, colorectal cancer, and squamous cell carcinomas. The development of multiple anticancer agents against EGFR diminished the progression and metastasis of tumors. Some of the most versatile therapeutic anti-EGFR agents include the monoclonal antibodies (mAbs), demonstrating success in clinical settings when used in combination with cytotoxic treatments, such as chemotherapy and/or radiation. We thus discuss the development and application of two of the most notable therapeutic mAbs, cetuximab, and panitumumab, currently utilized in various EGFR-related epithelial cancers.

Involvement of the epidermal growth factor receptor in IL-13-mediated corticosteroid-resistant airway inflammation

BACKGROUND

Effective treatment for severe asthma is a significant unmet need. While eosinophilic inflammation caused by type 2 cytokines is responsive to corticosteroid and biologic therapies, many severe asthmatics exhibit corticosteroid-unresponsive mixed granulocytic inflammation.

OBJECTIVE

Here, we tested the hypothesis that the pro-allergic cytokine, IL-13, can drive both corticosteroid-sensitive and corticosteroid-resistant responses.

RESULTS

By integration of in vivo and in vitro models of IL-13-driven inflammation, we identify a role for the epidermal growth factor receptor (EGFR/ERBB1) as a mediator of corticosteroid-unresponsive inflammation and bronchial hyperresponsiveness driven by IL-13. Topological data analysis using human epithelial transcriptomic data from the U-BIOPRED cohort identified severe asthma groups with features consistent with the presence of IL-13 and EGFR/ERBB activation, with involvement of distinct EGFR ligands. Our data suggest that IL-13 may play a dual role in severe asthma: on the one hand driving pathologic corticosteroid-refractory mixed granulocytic inflammation, but on the other hand underpinning beneficial epithelial repair responses, which may confound responses in clinical trials.

CONCLUSION AND CLINICAL RELEVANCE

Detailed dissection of those molecular pathways that are downstream of IL-13 and utilize the ERBB receptor and ligand family to drive corticosteroid-refractory inflammation should enhance the development of new treatments that target this sub-phenotype(s) of severe asthma, where there is an unmet need.

Protein crystallization promotes type 2 immunity and is reversible by antibody treatment

Although spontaneous protein crystallization is a rare event in vivo, Charcot-Leyden crystals (CLCs) consisting of galectin-10 (Gal10) protein are frequently observed in eosinophilic diseases, such as asthma. We found that CLCs derived from patients showed crystal packing and Gal10 structure identical to those of Gal10 crystals grown in vitro. When administered to the airways, crystalline Gal10 stimulated innate and adaptive immunity and acted as a type 2 adjuvant. By contrast, a soluble Gal10 mutein was inert. Antibodies directed against key epitopes of the CLC crystallization interface dissolved preexisting CLCs in patient-derived mucus within hours and reversed crystal-driven inflammation, goblet-cell metaplasia, immunoglobulin E (IgE) synthesis, and bronchial hyperreactivity (BHR) in a humanized mouse model of asthma. Thus, protein crystals may promote hallmark features of asthma and are targetable by crystal-dissolving antibodies.

Efficacy of an Inhaled IL-13 Antibody Fragment in a Model of Chronic Asthma

RATIONALE

IL-13 is an important cytokine implicated in the pathogenesis of allergic asthma and is an attractive target for an inhaled therapeutic.

OBJECTIVE

To investigate the efficacy of CDP7766, a nebulized inhaled anti-IL-13 monoclonal antibody Fab fragment, in a model of allergic asthma in cynomolgus macaques naturally sensitized to Ascaris suum.

METHODS

CDP7766 was nebulized using a vibrating-membrane nebulizer on the basis of eFlow technology. The aerosol generated was analyzed to determine the particle size profile and the biophysical and functional properties of CDP7766. Nebulized CDP7766 (0.1-60 mg/animal, once daily for 5 d) was delivered via the inhaled route.

MEASUREMENTS AND MAIN RESULTS

The investigational eFlow nebulizer used in this study generated a respirable aerosol of CDP7766 with no evidence of degradation, loss of potency, aggregation, or formation of particulates. Inhaled CDP7766 was well tolerated in the model (no adverse effects related to local irritation) and significantly inhibited BAL allergen-induced cytokine and chemokine upregulation (60 mg vs. vehicle: eotaxin-3, P < 0.0008; MIP [macrophage inflammatory protein]-1β, IL-8, IFN-γ, P ≤ 0.01). CDP7766 significantly inhibited the increase in pulmonary resistance stimulated by inhaled allergen, measured 15 minutes and 24 hours after allergen challenge.

CONCLUSION

Inhaled CDP7766 potently inhibited the function of IL-13 generated during the airway response to inhaled allergen in cynomolgus macaques, demonstrating the potential of inhaled anti-IL-13 therapeutics for the treatment of allergic asthma.

Blockade of EGFR Activation Promotes TNF-Induced Lung Epithelial Cell Apoptosis and Pulmonary Injury

Pneumonitis is the leading cause of death associated with the use of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) against non-small cell lung cancer (NSCLC). However, the risk factors and the mechanism underlying this toxicity have not been elucidated. Tumor necrosis factor (TNF) has been reported to transactivate EGFR in pulmonary epithelial cells. Hence, we aimed to test the hypothesis that EGFR tyrosine kinase activity regulates TNF-mediated bronchial epithelial cell survival, and that inhibition of EGFR activity increases TNF-induced lung epithelial cell apoptosis. We used surfactant protein C (SPC)-TNF transgenic (tg) mice which overexpress TNF in the lungs. In this model, gefitinib, an EGFR-TKI, enhanced lung epithelial cell apoptosis and lymphocytic inflammation, indicating that EGFR tyrosine kinase prevents TNF-induced lung injury. Furthermore, IL-17A was significantly upregulated by gefitinib in SPC-TNF tg mice and p38MAPK activation was observed, indicative of a pathway involved in lung epithelial cell apoptosis. Moreover, in lung epithelial cells, BEAS-2B, TNF stimulated EGFR transactivation via the TNF-α-converting enzyme in a manner that requires heparin binding (HB)-EGF and transforming growth factor (TGF)-α. These novel findings have significant implications in understanding the role of EGFR in maintaining human bronchial epithelial cell homeostasis and in NSCLC treatment.

Srolo Bzhtang, a traditional Tibetan medicine formula, inhibits cigarette smoke induced airway inflammation and muc5ac hypersecretion via suppressing IL-13/STAT6 signaling pathway in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Srolo Bzhtang (SBT), a traditional Tibetan medicine formula, was composed of three herbs, Solms-Laubachia eurycarpa, Bergenia purpurascens, Glycyrrhiza uralensis, and one lac, and was first documented in the ancient Tibetan medical work Four Medical Tantras (rGyud-bzhi) in the eighth century AD. It has been widely used to treat lung "phlegm-heat" syndromes such as chronic bronchitis and chronic obstructive pulmonary disease (COPD).

OBJECTIVE

The aim of this study was to evaluate the potential influences of aqueous extract of SBT on airway inflammation and mucus secretion and to reveal the underlying mechanism in a rat model of cigarette smoke (CS)-induced chronic bronchitis (CB).

MATERIALS AND METHODS

Sixty male Sprague-Dawley rats were randomly divided to six groups: control (room air exposure), model (CS exposure), DEX (CS exposure and 0.2 mg/kg/day dexamethasone), and three SBT (CS exposure and 1.67, 2.50, and 3.34 g/kg/day SBT) groups. DEX and the three doses of SBT were administered by oral gavage every day for eight weeks. Pathological changes and mucus expression in the lung tissue were determined by hematoxylin and eosin (H&E), Alcian blue-periodic acid-Schiff (AB-PAS) and immunohistochemical staining. The levels of cytokines in bronchoalveolar lavage fluid (BALF) were assessed by ELISA. Western blot analysis and qRT-PCR were performed to explore the effects of SBT on the expression of IL-13, STAT6 and MUC5AC.

RESULTS

Pretreatment with SBT attenuated the TNF-α, IL-8, IL-13 expression levels in BALF and the inflammatory cell infiltration in bronchial walls and peribronchial lung tissue. SBT exhibited a dose-dependent downregulation of MUC5AC expression as assessed by AB-PAS and immunohistochemical staining. The protein and mRNA levels of IL-13, STAT6/p-STAT6 and MUC5AC were also downregulated by SBT preconditioning.

CONCLUSION

These results for the first time demonstrated that SBT exhibited protective effects on CS-induced airway inflammation and MUC5AC hypersecretion, which might be related to the downregulation of the IL-13/STAT6 signaling pathway.

Emerging therapeutic potential of group 2 innate lymphoid cells in acute kidney injury

Acute kidney injury (AKI) remains a global challenge and, despite the availability of dialysis and transplantation, can be fatal. Those that survive an AKI are at increased risk of developing chronic kidney disease and end stage renal failure. Understanding the fundamental mechanisms underpinning the pathophysiology of AKI is critical for developing novel strategies for diagnosis and treatment. A growing body of evidence indicates that amplifying type 2 immunity may have therapeutic potential in kidney injury and disease. Of particular interest are the recently described subset of innate immune cells, termed group 2 innate lymphoid cells (ILCs). Group 2 ILCs are crucial tissue-resident immune cells that maintain homeostasis and regulate tissue repair at multiple organ sites, including the kidney. They are critical mediators of type 2 immune responses following infection and injury. The existing literature suggests that activation of group 2 ILCs and production of a local type 2 immune milieu is protective against renal injury and associated pathology. In this review, we describe the emerging role for group 2 ILCs in renal homeostasis and repair. We provide an in-depth discussion of the most recent literature that use preclinical models of AKI and assess the therapeutic effect of modulating group 2 ILC function. We debate the potential for targeting these cells as novel cellular therapies in AKI and discuss the implications for future studies and translation. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Human lung tissue provides highly relevant data about efficacy of new anti-asthmatic drugs

Subgroups of patients with severe asthma are insensitive to inhaled corticosteroids and require novel therapies on top of standard medical care. IL-13 is considered one of the key cytokines in the asthma pathogenesis, however, the effect of IL-13 was mostly studied in rodents. This study aimed to assess IL-13 effect in human lung tissue for the development of targeted therapy approaches such as inhibition of soluble IL-13 or its receptor IL-4Rα subunit. Precision-cut lung slices (PCLS) were prepared from lungs of rodents, non-human primates (NHP) and humans. Direct effect of IL-13 on human lung tissue was observed on inflammation, induction of mucin5AC, and airway constriction induced by methacholine and visualized by videomicroscopy. Anti-inflammatory treatment was evaluated by co-incubation of IL-13 with increasing concentrations of IL-13/IL-13 receptor inhibitors. IL-13 induced a two-fold increase in mucin5AC secretion in human bronchial tissue. Additionally, IL-13 induced release of proinflammatory cytokines eotaxin-3 and TARC in human PCLS. Anti-inflammatory treatment with four different inhibitors acting either on the IL-13 ligand itself (anti-IL-13 antibody, similar to Lebrikizumab) or the IL-4Rα chain of the IL-13/IL-4 receptor complex (anti-IL-4Rα #1, similar to AMG 317, and #2, similar to REGN668) and #3 PRS-060 (a novel anticalin directed against this receptor) could significantly attenuate IL-13 induced inflammation. Contrary to this, IL-13 did not induce airway hyperresponsiveness (AHR) in human and NHP PCLS, although it was effective in rodent PCLS. Overall, this study demonstrates that IL-13 stimulation induces production of mucus and biomarkers of allergic inflammation in human lung tissue ex-vivo but no airway hyperresponsiveness. The results of this study show a more distinct efficacy than known from animals models and a clear discrepancy in AHR induction. Moreover, it allows a translational approach in inhibitor profiling in human lung tissue.

Intranasal curcumin protects against LPS-induced airway remodeling by modulating toll-like receptor-4 (TLR-4) and matrixmetalloproteinase-9 (MMP-9) expression via affecting MAP kinases in mouse model

OBJECTIVE

Bacterial infections can exacerbate asthmatic inflammation depending on lipopolysaccharide (LPS) composition, the outermost component of cell wall, its exposure timings as well as host's immune status. In present study, Balb/c mice were exposed to antigen (ovalbumin) and LPS simultaneously to establish an asthmatic model. Curcumin (diferuloylmethane), well known for its anti-inflammatory potential, was administered through intranasal route 1 h before LPS and OVA (ovalbumin) exposure to evaluate its efficacy against airway structural changes.

METHODS

Inflammatory cell infiltration in lungs was measured by flow cytometry and further eosinophils were especially measured by immunofluorescence detection of major basic protein (MBP) as marker of eosinophilc granule protein. We also measured reactive oxygen species (ROS) in BALF by spectrofluorometry. MMP-9 activity was evaluated by gelatin zymography and mRNA expressions of MMP-9, TIMP-1, TGF-β1, IL-13, Collagen-1 and TLR-4 were measured in lungs. Protein expression of MAP kinases (P-ERK, P-JNK, P-p38), TLR-4, Cox-2, Lox-5 and Eotaxin was measured by western blotting. Hydroxyproline level and masson's trichrome staining were used to evaluate collagen deposition in lung.

RESULTS

Exposure to LPS (0.1 µg) exacerbates airway inflammation and induces structural changes in lungs by enhanced ROS production, collagen deposition, expression of genes involved in airway remodeling and activation of MAP kinases pathway enzymes. Intranasal curcumin pretreatment had significantly suppressed inflammatory mediators and airway remodeling proteins.

CONCLUSION

Our results strongly suggest that intranasal curcumin effectively protects LPS-induced airway inflammation and structural changes by modulating genes involved in airway remodeling in safer way; hence, it can be considered as supplementary alternative towards asthma treatments.

Clarithromycin suppresses IL-13-induced goblet cell metaplasia via the TMEM16A-dependent pathway in guinea pig airway epithelial cells

BACKGROUND

Transmembrane protein 16A (TMEM16A) is associated with mucus secretion and ion transport in asthma. Clarithromycin (CAM) is reported to inhibit IL-13-induced goblet cell metaplasia. However, the effect of CAM on TMEM16A function and expression remains unclear.

METHODS

Tracheal epithelial cells from guinea pigs were cultured for ~14 days at an air-liquid interface in medium containing IL-13 (10 ng/ml) in the absence or presence of CAM (20 µg/ml) or a TMEM16A inhibitor, T16Ainh-A01 (10 µg/ml). Electrophysiological studies were performed by Ussing׳s short-circuit technique. The cells were used for immunofluorescence staining with antibodies against TMEM16A, MUC5AC, and α-tubulin. The cells were also examined by transmission electron microscopy. TMEM16A protein levels in the cell lysates were determined by ELISA. For the in vivo study, guinea pigs were treated intratracheally with IL-13 in the absence or presence of CAM or T16Ainh-A01.

RESULTS

CAM decreased the MUC5AC-positive cells and reduced TMEM16A expression in them and increased the α-tubulin-positive cells. CAM inhibited TMEM16A protein levels in a dose-dependent manner, and decreased UTP-induced Cl ion transport. In cells treated with IL-13 for 24 h, TMEM16A appeared prior to MUC5AC protein expression, and was inhibited by CAM. In the in vivo study, CAM inhibited IL-13-induced goblet cell metaplasia and TMEM16A expression. The inhibitory effects of CAM were similar to those of T16Ainh-A01.

CONCLUSIONS

CAM inhibited IL-13-induced TMEM16A expression, Cl ion transport and goblet cell metaplasia both in vitro and in vivo. CAM may thus improve airway mucociliary differentiation by attenuating TMEM16A expression in IL-13-related asthma.

Gene expression analysis of Atlantic salmon gills reveals mucin 5 and interleukin 4/13 as key molecules during amoebic gill disease

Amoebic gill disease (AGD) is one of the main diseases affecting Atlantic salmon (Salmo salar L.) mariculture. Hallmarks of AGD are hyperplasia of the lamellar epithelium and increased production of gill mucus. This study investigated the expression of genes involved in mucus secretion, cell cycle regulation, immunity and oxidative stress in gills using a targeted 21-gene PCR array. Gill samples were obtained from experimental and natural Neoparamoeba perurans infections, and sampling points included progressive infection stages and post-freshwater treatment. Up-regulation of genes related to mucin secretion and cell proliferation, and down-regulation of pro-inflammatory and pro-apoptotic genes were associated with AGD severity, while partial restoration of the gill homeostasis was detected post-treatment. Mucins and Th2 cytokines accoun ted for most of the variability observed between groups highlighting their key role in AGD. Two mucins (muc5, muc18) showed differential regulation upon disease. Substantial up-regulation of the secreted muc5 was detected in clinical AGD, and the membrane bound muc18 showed an opposite pattern. Th2 cytokines, il4/13a and il4/13b2, were significantly up-regulated from 2 days post-infection onwards, and changes were lesion-specific. Despite the differences between experimental and natural infections, both yielded comparable results that underline the importance of the studied genes in the respiratory organs of fish, and during AGD progression.

Anti-inflammatory effect of wogonin on allergic responses in ovalbumin-induced allergic rhinitis in the mouse

Background

Wogonin is commonly used for the treatment of allergic diseases. However, neither its precise effect in preventing allergic rhinitis (AR) nor its mechanism of action are known.

Objectives

In this study, the effect of wogonin on allergic responses in ovalbumin (OVA) induced AR was investigated in mice.

Methods

BALB/c mice were sensitized with intraperitoneal (i.p.) OVA and then challenged intranasally with OVA. Wogonin (10 and 30 mg/kg) was given to the treatment groups, and the effect of wogonin on the release of allergic inflammatory mediators, specifically OVA-specific immunoglobulin E (IgE) and inflammatory cytokines, was explored. Eosinophil infiltration and the levels of interleukin (IL) 5 and IL-13 were measured by immunohistochemistry.

Results

In mice with AR, wogonin decreased OVA-specific IgE levels in serum, and the levels of the cytokines IL-4, IL-5, IL-13, eotaxin, and RANTES in nasal lavage fluid. Serum levels of IL-4, IL-5, and IL-13 were lower in both groups of wogonin-pretreated mice than in the OVA group. A reduction in eosinophil infiltration of the nasal mucosa and inhibition of the expression of IL-5 and IL-13 were also noted in the treated groups.

Conclusion

Wogonin induced antiallergic effects in a murine model of AR by decreasing the infiltration of eosinophils and levels of T-helper type 2 cytokines. Thus, wogonin merits consideration as a therapeutic agent for treating AR.

Regulatory effects of IL-15 on allergen-induced airway obstruction

BACKGROUND

Airway obstruction is a physiologic feature of asthma, and IL-15 might have an important role in asthma pathogenesis.

OBJECTIVE

We tested the hypothesis that regulation of IL-15 is critical for preservation of allergen-induced airway hyperresponsiveness (AHR), airway resistance, and compliance in response to methacholine.

METHODS

Airway inflammation, AHR, resistance, and compliance were assessed in Il15 gene-deficient mice and IL-15-overexpressing mice in an allergen-induced murine model of asthma. We assessed eosinophil numbers by using anti-major basic protein immunostaining, goblet cell hyperplasia by using periodic acid-Schiff staining, and cytokine and chemokine levels by performing quantitative PCR and ELISA.

RESULTS

We made a novel observation that IL-15 deficiency promotes baseline airway resistance in naive mice. Moreover, rIL-15 delivery to the lung downregulates expression of proinflammatory cytokines and improves allergen-induced AHR, airway resistance, and compliance. These observations were further validated in doxycycline-inducible CC10-IL-15 bitransgenic mice. Doxycycline-exposed, Aspergillus species extract-challenged CC10-IL-15 bitransgenic mice exhibited significantly reduced levels of proinflammatory cytokines (IL-4, IL-5, and IL-13) and decreased goblet cell hyperplasia. Airway obstruction, including AHR and airway resistance, was diminished in allergen-challenged doxycycline-exposed compared with non-doxycycline-exposed CC10-IL-15 bitransgenic mice. Mechanistically, we observed that IL-15-mediated protection of airway obstruction is associated with induced IFN-γ- and IL-10-producing regulatory CD4+CD25+ forkhead box p3 (Foxp3)+ T cells. Additionally, we found that a human IL-15 agonist (ALT-803) improved airway resistance and compliance in an experimental asthma model.

CONCLUSION

We report our novel finding that IL-15 has a potent inhibitory effect on the airway obstruction that occurs in response to environmental allergens.

IL-13 in LPS-Induced Inflammation Causes Bcl-2 Expression to Sustain Hyperplastic Mucous cells

Exposure to lipopolysaccharides (LPS) causes extensive neutrophilic inflammation in the airways followed by mucous cell hyperplasia (MCH) that is sustained by the anti-apoptotic protein, Bcl-2. To identify inflammatory factor(s) that are responsible for Bcl-2 expression, we established an organ culture system consisting of airway epithelial tissue from the rat nasal midseptum. The highest Muc5AC and Bcl-2 expression was observed when organ cultures were treated with brochoalveolar lavage (BAL) fluid harvested from rats 10 h post LPS instillation. Further, because BAL harvested from rats depleted of polymorphonuclear cells compared to controls showed increased Bcl-2 expression, analyses of cytokine levels in lavages identified IL-13 as an inducer of Bcl-2 expression. Ectopic IL-13 treatment of differentiated airway epithelial cells increased Bcl-2 and MUC5AC expression in the basal and apical regions of the cells, respectively. When Bcl-2 was blocked using shRNA or a small molecule inhibitor, ABT-263, mucous cell numbers were reduced due to increased apoptosis that disrupted the interaction of Bcl-2 with the pro-apoptotic protein, Bik. Furthermore, intranasal instillation of ABT-263 reduced the LPS-induced MCH in bik +/+ but not bik -/- mice, suggesting that Bik mediated apoptosis in hyperplastic mucous cells. Therefore, blocking Bcl-2 function could be useful in reducing IL-13 induced mucous hypersecretion.

Persistent induction of goblet cell differentiation in the airways: Therapeutic approaches

Dysregulated induction of goblet cell differentiation results in excessive production and retention of mucus and is a common feature of several chronic airways diseases. To date, therapeutic strategies to reduce mucus accumulation have focused primarily on altering the properties of the mucus itself, or have aimed to limit the production of mucus-stimulating cytokines. Here we review the current knowledge of key molecular pathways that are dysregulated during persistent goblet cell differentiation and highlights both pre-existing and novel therapeutic strategies to combat this pathology.

Sirtuin 3 Deregulation Promotes Pulmonary Fibrosis

Oxidative stress leads to alveolar epithelial cell injury and fibroblast-myofibroblast differentiation (FMD), key events in the pathobiology of pulmonary fibrosis (PF). Sirtuin 3 (SIRT3) is a mitochondrial protein deacetylase regulator of antioxidant response and mitochondrial homeostasis. Here, we demonstrate reduced SIRT3 expression in the lungs of old mice compared to young mice, as well as in two murine models of PF. The analysis of the pattern of SIRT3 expression in the lungs of patients with PF revealed low SIRT3 staining within the fibrotic regions. We also demonstrated, using murine models of PF and human lung fibroblasts, that reduced SIRT3 expression in response to transforming growth factor beta 1 (TGFβ1) promotes acetylation (inactivation) of major oxidative stress response regulators, such as SOD2 and isocitrate dehydrogenase 2. Reduction of SIRT3 in human lung fibroblasts promoted FMD. By contrast, overexpression of SIRT3 attenuated TGFβ1-mediated FMD and significantly reduced the levels of SMAD family member 3 (SMAD3). Resveratrol induced SIRT3 expression and ameliorated acetylation changes induced by TGFβ1. We demonstrated that SIRT3-deficient mice are more susceptible to PF compared to control mice, and concomitantly exhibit enhanced SMAD3 expression. Collectively, these data define a SIRT3/TGFβ1 interaction during aging that may play a significant role in the pathobiology of PF.

MUC18 regulates IL-13-mediated airway inflammatory response

OBJECTIVE

To evaluate the effects of MUC18 on IL-13-mediated airway inflammatory responses in human airway epithelial cells and in mice.

MATERIALS

Primary normal human tracheobronchial epithelial (HTBE) cells, wild-type (WT) and Muc18 knockout (KO) mice, and mouse tracheal epithelial cells (mTECs) were utilized.

TREATMENT

Cultured HTBE cells treated with MUC18 siRNA or MUC18 expressing lentivirus were incubated with IL-13 (10 ng/mL) for 24 h. Mice were intranasally instilled with 500 ng of IL-13 for 3 days. mTECs were treated with IL-13 (10 ng/mL) for 3 days.

METHODS

PCR was used to measure mRNA expression. Western Blot and ELISAs were used to quantify protein expression. Cytospins of bronchoalveolar lavage (BAL) cells were used to obtain leukocyte differentials.

RESULTS

MUC18 siRNA reduced IL-13-mediated eotaxin-3 (183 ± 44 vs. 380 ± 59 pg/mL, p < 0.05), while MUC18 overexpression increased IL-13-mediated eotaxin-3 (95 ± 3 vs. 58 ± 3 pg/mL, p < 0.05) in HTBE cells. IL-13-treated Muc18 KO mice had a lower percentage of neutrophils in BAL than WT mice (25 ± 3 vs. 35 ± 3%, p = 0.0565).

CONCLUSIONS

These results implicate MUC18 as a potential enhancer of airway inflammation in a type 2 cytokine (e.g., IL-13) milieu.

Viruses and bacteria in Th2-biased allergic airway disease

Allergic airway diseases are typically characterized by a type 2-biased inflammation. Multiple distinct viruses and bacteria have been detected in the airways. Recently, it has been confirmed that the microbiome of allergic individuals differs from that of healthy subjects, showing a close relationship with the type 2 response in allergic airway disease. In this review, we summarize the recent findings on the prevalence of viruses and bacteria in type 2-biased airway diseases and on the mechanisms employed by viruses and bacteria in propagating type 2 responses. The understanding of the microbial composition and postinfectious immune programming is critical for the reconstruction of the normal microflora and immune status in allergic airway diseases.

Antiallergic Effects of Trichostatin A in a Murine Model of Allergic Rhinitis

Objectives

Trichostatin A (TSA), an inhibitor of histone deacetylase, has been shown to play an important role in attenuating asthmatic inflammation. However, the effect of TSA in allergic rhinitis is not known. The aims of this study were to investigate the effect of TSA on allergic nasal inflammation and on the induction of regulatory T cells in a murine model of allergic rhinitis.

Methods

BALB/c mice were sensitized intraperitoneally with ovalbumin (OVA) and then challenged intranasally with OVA. TSA (1 mg/kg) was given to the treatment group, and multiple parameters of allergic responses were evaluated to determine the effects of TSA on allergic rhinitis. Allergic nasal symptom scores, including frequency of rubbing and sneezing, were checked. Eosinophil infiltrations were stained with Chromotrope 2R, and the expression levels of OVA-specific IgE, T-helper 1 (Th1) cytokine (interferon-gamma [IFN-γ]), Th2 cytokines (interleukin [IL] 4 and IL-5) and Treg (Foxp3, IL-10, and transforming growth factor-beta [TGF-β]) were measured by quantitative reverse transcription-polymerase chain reaction or enzyme-linked immunosorbent assay.

Results

TSA reduced the scores of allergic nasal symptoms and the amount of eosinophil infiltration into the nasal mucosa. TSA suppressed OVA-specific IgE levels and reduced expression of the IL-4 and IL-5. However, the expression of IFN-γ was unchanged in the treatment group. The levels of Foxp3, IL-10, and TGF-β were increased in pretreatment with TSA as compared to control group.

Conclusion

This study shows that TSA induced antiallergic effects by decreasing eosinophilic infiltration and Th2 cytokines in a murine model of allergic rhinitis via regulation of Tregs. Thus, TSA may be considered a potentially therapeutic agent in treating allergic rhinitis.

Asthma therapy and its effect on airway remodelling

Asthma remains a major health problem with significant morbidity, mortality and economic costs. In asthma, airway remodelling, which refers to all the microscopic structural changes seen in the airway tissue, has been recognised for many decades and remains one of the defining characteristics of the disease; however, it is still poorly understood. The detrimental pathophysiological consequences of some features of remodelling, like increased airway smooth muscle mass and subepithelial fibrosis, are well documented. However, whether targeting these by therapy would be beneficial is unknown. Although the prevailing thinking is that remodelling is an abnormal response to persistent airway inflammation, recent evidence, especially from studies of remodelling in asthmatic children, suggests that the two processes occur in parallel. The effects of asthma therapy on airway remodelling have not been studied extensively due to the challenges of obtaining airway tissue in the context of clinical trials. Corticosteroids remain the cornerstone of asthma therapy, and their effects on remodelling have been better studied than other drugs. Bronchial thermoplasty is the only asthma therapy to primarily target remodelling, although how it results in the apparent clinical benefits seen is not exactly clear. In this article we discuss the mechanisms of airway remodelling in asthma and review the effects of conventional and novel asthma therapies on the process.

Subtypes of asthma defined by epithelial cell expression of messenger RNA and microRNA

Human asthma can be subcategorized in several ways, but one powerful approach is to subtype asthma on the basis of underlying cellular and molecular mechanisms. Groups of patients with a disease that share a common underlying biology are termed an "endotype." Endotypes of asthma have been studied at both the cellular level (by cytological examination of induced sputum) and, increasingly, at the molecular level. Genome-wide analyses of mRNA expression within the lung have been useful in the identification of molecular endotypes of asthma and point to protein biomarkers of those endotypes that can be measured in the blood. More recently, studies of microRNA expression in airway epithelial cells in asthma have identified additional candidate biomarkers of asthma endotypes. One potentially valuable property of microRNAs is that they can also be measured in extracellular fluids and therefore have the potential to serve directly as noninvasively measured biomarkers.

The impact of viral genotype on pathogenesis and disease severity: respiratory syncytial virus and human rhinoviruses

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection (LRI) and viral death in infants. RSV disease in infants is characterized by epithelial desquamation, neutrophilic bronchiolitis and pneumonia and obstructive pulmonary mucus. Human rhinoviruses (HRVs) are by far the most common cause of symptomatic upper respiratory tract infection (URI) in people and are more recently appreciated as a significant cause of LRI. RSV and HRV are also implicated in asthma pathogenesis. Within both RSV and HRV, viral genetic differences play a role in disease severity and/or prevalence in patient populations, and viral genetic differences affect pathogenesis. Here, we review data on how viral genetic differences impact disease using RSV and HRV as examples, including effects on the host immune response. Virus genotype–phenotype relationships can be exploited in the laboratory to gain insight into mechanisms by which respiratory viruses modulate host immune responses and cause disease.

Effects of chronic exposure to Aspergillus fumigatus on epidermal growth factor receptor expression in the airway epithelial cells of asthmatic rats

Epidemiologic studies suggest that increased concentrations of airborne spores of Aspergillus fumigatus closely relate to asthma aggravation. Chronic exposure to A. fumigatus aggravates airway inflammation, remodeling, and airway hyperresponsiveness in asthmatic rats. The effects of chronic exposure to A. fumigatus on epidermal growth factor receptor (EGFR) expression in the airway epithelial cells of asthmatic rats remain unclear. This study aimed to investigate the effects of chronic exposure to A. fumigatus on injury and shedding of airway epithelium, goblet cell metaplasia, and EGFR expression in the airway epithelial cells of asthmatic rats. A rat model of chronic asthma was established using ovalbumin (OVA) sensitization and challenge. Rats with chronic asthma were then exposed to long-term inhalation of spores of A. fumigatus, and the dynamic changes in injury and shedding of airway epithelium, goblet cell metaplasia, and EGFR expression were observed and analyzed. Chronic exposure to A. fumigatus could aggravate airway epithelial cell damage, upregulate the expression of EGFR and its ligands EGF and TGF-α, promote goblet cell metaplasia, and increase airway responsiveness in rats with asthma. Chronic exposure to A. fumigatus upregulates the expression of EGFR and its ligands in asthmatic rats. The EGFR pathway may play a role in asthma aggravation induced by exposure to A. fumigatus.

IL-33 promotes the induction and maintenance of Th2 immune responses by enhancing the function of OX40 ligand

BACKGROUND

In Th2 immune responses, TSLP is a key player by induction of OX40-ligand (OX40L) on dendritic cells (DCs), which is the trigger to induce Th2 cell-mediated allergic cascade. Thus, TSLP-DC-OX40L axis might be the principal pathway in the inflammatory cascades in atopic dermatitis and asthma. IL-33, which is produced by epithelial cells, has been implicated in the Th2 immune responses and pathogenesis of the allergic disorders. However, the role of IL-33 in the Th2-polarizing TSLP-DC-OX40L axis still remains largely elusive. We focused on the ability of IL-33 to promote OX40L-mediated Th2 responses.

METHODS

Purified human naïve or memory CD4+ T cells were stimulated with recombinant OX40L or TSLP-treated DCs (TSLP-DCs) in the presence of IL-33, and the cytokine production by the primed T cells was examined. We also performed immunohistochemical analyses for the expression of IL-33 in specimens of lymph node and skin from the patients with atopic dermatitis.

RESULTS

IL-33 remarkably enhanced TSLP-DCs-driven or OX40L-driven Th2 responses from naïve T cells and the Th2 functional attributes of CRTH2+ CD4+ Th2 memory cells by the increased production of IL-5, IL-9, and IL-13. In addition, IL-33 was expressed in the nuclei of epithelial cells in not only skin lesion but also lymph nodes of the patient with atopic dermatitis, suggesting a specialized role in adaptive T cell-priming phase.

CONCLUSIONS

IL-33 works as a positive regulator of TSLP-DC-OX40L axis that initiates and maintains the Th2 cell-mediated inflammatory responses, and therefore, it would be a new therapeutic target for the treatment of allergic disorders.

EGF-induced bronchial epithelial cells drive neutrophil chemotactic and anti-apoptotic activity in asthma

Chronic damage and repair of the bronchial epithelium are features of asthma. We have previously reported that ex vivo stimulation of normal bronchial epithelial cells with epidermal growth factor (EGF), a key factor of epithelial repair, enhances the mechanisms of neutrophil accumulation, thereby promoting neutrophil defences during acute injury but potentially enhancing inflammation in chronic airway diseases. We have now sought to (i) determine whether this EGF-dependent pro-neutrophil activity is increased in asthma, where EGF and its epithelial receptor are over-expressed, and (ii) elucidate some of the mechanisms underlying this asthmatic epithelial-neutrophil interaction. Primary bronchial epithelial cells (PBEC) from healthy subjects, mild asthmatics and moderate-to-severe asthmatics (Mod/Sev) were stimulated with EGF, a model that mimics a repairing epithelium. Conditioned culture media (EGF-CM) were assessed for neutrophil chemotactic and anti-apoptotic activities and inflammatory mediator production. EGF induced the epithelium to produce soluble mediators with neutrophil chemotactic (p<0.001) and pro-survival (p = 0.021) activities which were related to the clinical severity of asthma (trend p = 0.010 and p = 0.009, respectively). This was associated with enhanced IL-6, IL-8, GM-CSF and TNF-α release, and cytokine-neutralising experiments using EGF-CM from Mod/Sev asthmatics demonstrated a role for GM-CSF in neutrophil survival (p<0.001). Pre-treatment of neutrophils with specific inhibitors of the myeloid-restricted class I phosphatidylinositol-3-OH kinase (PI(3)K) isoforms showed that the EGF-CM from Mod/Sev asthmatics depended on the γ (p<0.021) but not δ isoforms, while neutrophil survival required multiple class I PI(3)Ks. The EGF-induced chemotactic, but not pro-survival activity, involved RhoA signaling in neutrophils (p = 0.012). EGF whose activity is upregulated in asthma induces ex vivo the epithelium from asthmatic patients to produce pro-neutrophil activities; these are related to asthma severity and, in moderate-to-severe asthmatics, involves class IB PI(3)Kγ signaling, providing a potential therapeutic target for neutrophilic forms of asthma.