Elimination of IL-13 reverses established goblet cell metaplasia into ciliated epithelia in airway epithelial cell culture

Seihaito, a Kampo medicine, attenuates IL-13-induced mucus production and goblet cell metaplasia

Goblet cell hyperplasia and increased mucus production are features of airway diseases, including asthma, and excess airway mucus often worsens these conditions. Even steroids are not uniformly effective in mucus production in severe asthma, and new therapeutic options are needed. Seihaito is a Japanese traditional medicine that is used clinically as an antitussive and expectorant. In the present study, we examined the effect of Seihaito on goblet cell differentiation and mucus production. In in vitro studies, using air-liquid interface culture of guinea-pig tracheal epithelial cells, Seihaito inhibited IL-13-induced proliferation of goblet cells and MUC5AC, a major component of mucus production. Seihaito suppressed goblet cell-specific gene expression, without changing ciliary cell-specific genes, suggesting that it inhibits goblet cell differentiation. In addition, Seihaito suppressed MUC5AC expression in cells transfected with SPDEF, a transcription factor activated by IL-13. Furthermore, Seihaito attenuated in vivo goblet cell proliferation and MUC5AC mRNA expression in IL-13-treated mouse lungs. Collectively, these findings demonstrated that Seihaito has an inhibitory effect on goblet cell differentiation and mucus production, which is at least partly due to the inhibition of SPDEF.

German cockroach extract prevents IL-13-induced CCL26 expression in airway epithelial cells through IL-13 degradation

Inhaled aeroallergens can directly activate airway epithelial cells (AECs). Exposure to cockroach allergens is a strong risk factor for asthma. Cockroach allergens mediate some of their effects through their serine protease activity; protease activity is also a major contributor to allergenicity. The Th2 cytokine interleukin-13 (IL-13) induces upregulation of the eosinophil chemotactic factor CCL26. CCL26 induces eosinophil migration in allergic inflammation. In this work, we studied the effect of cockroach proteases on IL-13-induced effects. Immersed cultures of the human bronchial epithelial cell line BEAS-2B and air-liquid interface (ALI) cultures of primary normal human bronchial epithelial (NHBE) cells were stimulated with IL-13, Blattella Germanica cockroach extract (CE), or both. IL-13-induced genes were analyzed with qRT-PCR. IL-13 induced upregulation of CCL26, periostin, and IL-13Rα2 in bronchial epithelial cells which were decreased by CE. CE was heat-inactivated (HICE) or pre-incubated with protease inhibitors. HICE and CE preincubated with serine protease inhibitors did not prevent IL-13-induced CCL26 upregulation. CE-degraded IL-13 and specific cleavage sites were identified. CE also decreased IL-4-induced CCL26 upregulation and degraded IL-4. Other serine proteases such as bovine trypsin and house dust mite (HDM) serine proteases did not have the same effects on IL-13-induced CCL26. We conclude that CE serine proteases antagonize IL-13-induced effects in AECs, and this CE effect is mediated primarily through proteolytic cleavage of IL-13. IL-13 cleavage by cockroach serine proteases may modulate CCL26-mediated effects in allergic airway inflammation by interfering directly with the pro-inflammatory effects of IL-13 in vivo.

Rhinovirus induces airway remodeling: what are the physiological consequences?

BACKGROUND

Rhinovirus infections commonly evoke asthma exacerbations in children and adults. Recurrent asthma exacerbations are associated with injury-repair responses in the airways that collectively contribute to airway remodeling. The physiological consequences of airway remodeling can manifest as irreversible airway obstruction and diminished responsiveness to bronchodilators. Structural cells of the airway, including epithelial cells, smooth muscle, fibroblasts, myofibroblasts, and adjacent lung vascular endothelial cells represent an understudied and emerging source of cellular and extracellular soluble mediators and matrix components that contribute to airway remodeling in a rhinovirus-evoked inflammatory environment.

MAIN BODY

While mechanistic pathways associated with rhinovirus-induced airway remodeling are still not fully characterized, infected airway epithelial cells robustly produce type 2 cytokines and chemokines, as well as pro-angiogenic and fibroblast activating factors that act in a paracrine manner on neighboring airway cells to stimulate remodeling responses. Morphological transformation of structural cells in response to rhinovirus promotes remodeling phenotypes including induction of mucus hypersecretion, epithelial-to-mesenchymal transition, and fibroblast-to-myofibroblast transdifferentiation. Rhinovirus exposure elicits airway hyperresponsiveness contributing to irreversible airway obstruction. This obstruction can occur as a consequence of sub-epithelial thickening mediated by smooth muscle migration and myofibroblast activity, or through independent mechanisms mediated by modulation of the β2 agonist receptor activation and its responsiveness to bronchodilators. Differential cellular responses emerge in response to rhinovirus infection that predispose asthmatic individuals to persistent signatures of airway remodeling, including exaggerated type 2 inflammation, enhanced extracellular matrix deposition, and robust production of pro-angiogenic mediators.

CONCLUSIONS

Few therapies address symptoms of rhinovirus-induced airway remodeling, though understanding the contribution of structural cells to these processes may elucidate future translational targets to alleviate symptoms of rhinovirus-induced exacerbations.

SUMOylation of Rho-associated protein kinase 2 induces goblet cell metaplasia in allergic airways

Allergic asthma is characterized by goblet cell metaplasia and subsequent mucus hypersecretion that contribute to the morbidity and mortality of this disease. Here, we explore the potential role and underlying mechanism of protein SUMOylation-mediated goblet cell metaplasia. The components of SUMOylaion machinery are specifically expressed in healthy human bronchial epithelia and robustly upregulated in bronchial epithelia of patients or mouse models with allergic asthma. Intratracheal suppression of SUMOylation by 2-D08 robustly attenuates not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Phosphoproteomics and biochemical analyses reveal SUMOylation on K1007 activates ROCK2, a master regulator of goblet cell metaplasia, by facilitating its binding to and activation by RhoA, and an E3 ligase PIAS1 is responsible for SUMOylation on K1007. As a result, knockdown of PIAS1 in bronchial epithelia inactivates ROCK2 to attenuate IL-13-induced goblet cell metaplasia, and bronchial epithelial knock-in of ROCK2(K1007R) consistently inactivates ROCK2 to alleviate not only allergen-induced airway inflammation, goblet cell metaplasia, and hyperreactivity, but IL-13-induced goblet cell metaplasia. Together, SUMOylation-mediated ROCK2 activation is an integral component of Rho/ROCK signaling in regulating the pathological conditions of asthma and thus SUMOylation is an additional target for the therapeutic intervention of this disease.

The Role of Staphylococcus aureus and Its Toxins in the Pathogenesis of Allergic Asthma

Bronchial asthma is one of the most common chronic diseases worldwide and affects more than 300 million patients. Allergic asthma affects the majority of asthmatic children as well as approximately 50% of adult asthmatics. It is characterized by a Th2-mediated immune response against aeroallergens. Many aspects of the overall pathophysiology are known, while the underlying mechanisms and predisposing factors remain largely elusive today. Over the last decade, respiratory colonization with Staphylococcus aureus (S. aureus), a Gram-positive facultative bacterial pathogen, came into focus as a risk factor for the development of atopic respiratory diseases. More than 30% of the world’s population is constantly colonized with S. aureus in their nasopharynx. This colonization is mostly asymptomatic, but in immunocompromised patients, it can lead to serious complications including pneumonia, sepsis, or even death. S. aureus is known for its ability to produce a wide range of proteins including toxins, serine-protease-like proteins, and protein A. In this review, we provide an overview of the current knowledge about the pathophysiology of allergic asthma and to what extent it can be affected by different toxins produced by S. aureus. Intensifying this knowledge might lead to new preventive strategies for atopic respiratory diseases.

High throughput virtual screening strategy to develop a potential treatment for bronchial asthma by targeting interleukin 13 cytokine signaling

Chronic inflammation in the airway passage leads to the clinical syndrome of pediatric asthma. Allergic reactions caused by bacterial, viral, and fungal infection lead to the immune dis-balance which primes T helper cells (Th2), a specific cluster of differentiation 4 (CD4) T cell differentiation. This favors the Th2-specific response by activating the inter-leukin 4/interleukin 13 (IL-4/IL-13) cytokine signaling and further activates the secretion of immunoglobulin E (IgE). IL-13 develops bronchial asthma by elevating bronchial hyperresponsiveness and enables production of immunoglobulin M (IgM) and IgE. The present study aims to target IL-13 signaling using molecular docking and understanding molecular dynamic simulation (MDS) to propose a compelling candidate to treat asthma. We developed a library of available allergic drugs (n=20) and checked the binding affinity against IL-13 protein (3BPN.pdb) through molecular docking and confirmed the best pose binding energy of -3.84 and -3.71 for epinephrine and guaifenesin, respectively. Studying the interaction of hydrogen bonds and Van der Walls, it is estimated that electrostatic energy is sufficient to interact with the active site of the IL-13 and has shown to inhibit inflammatory signaling. These computational results confirm epinephrine and guaifenesin as potential ligands showing potential inhibitory activity for IL-13 signaling. This study also suggests the designing of a new ligand and screening of a large cohort of drugs, in the future, to predict the exact mechanism to control the critical feature of asthma.

Surgical ciliated cyst after a mandibular surgery: a particular case report and review of the literature

Background

Surgical ciliated cyst is a rare clinicopathological lesion that appears in patients who undergo maxillofacial surgery. In this report we present a particular mandibular case and we discuss the etiopathogenesis and clinicopathological features of this pathology after reviewing the current literature, as well as the origin of its respiratory epithelial profile.

Case presentation

The patient is a 67-year-old male with an irregular radiolucency in a previously tooth extracted area of the mandible. The histopathological study revealed a cystic lesion with a connective wall with chronic inflammation, partially lined by a ciliated pseudostratified epithelium. PAS and CK19 stains showed the respiratory characteristics of this epithelium and confirmed the final diagnosis of mandibular surgical ciliated cyst.

Conclusions

Surgical ciliated cyst is an uncommon entity associated with maxillofacial surgical procedures with bone and nasal cartilage grafts. In our case, treatment with growth factors present in platelet-rich plasma could explain the respiratory changes observed in the cystic epithelial lining.”

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.

Xenopus epidermal and endodermal epithelia as models for mucociliary epithelial evolution, disease, and metaplasia

The Xenopus embryonic epidermis is a powerful model to study mucociliary biology, development, and disease. Particularly, the Xenopus system is being used to elucidate signaling pathways, transcription factor functions, and morphogenetic mechanisms regulating cell fate specification, differentiation and cell function. Thereby, Xenopus research has provided significant insights into potential underlying molecular mechanisms for ciliopathies and chronic airway diseases. Recent studies have also established the embryonic epidermis as a model for mucociliary epithelial remodeling, multiciliated cell trans-differentiation, cilia loss, and mucus secretion. Additionally, the tadpole foregut epithelium is lined by a mucociliary epithelium, which shows remarkable features resembling mammalian airway epithelia, including its endodermal origin and a variable cell type composition along the proximal-distal axis. This review aims to summarize the advantages of the Xenopus epidermis for mucociliary epithelial biology and disease modeling. Furthermore, the potential of the foregut epithelium as novel mucociliary model system is being highlighted. Additional perspectives are presented on how to expand the range of diseases that can be modeled in the frog system, including proton pump inhibitor-associated pneumonia as well as metaplasia in epithelial cells of the airway and the gastroesophageal region.

Ku70 modulation alleviates murine allergic asthma features and restores mitochondrial function in lungs

The airway epithelium is continuously exposed to a variety of pollutants and allergens, thanks to both natural and manmade environmental pollution. With numerous protective mechanisms, the airway epithelium protects the lungs. DNA repair mechanism is one such protective response and its failure could lead to the accumulation of DNA mutations. Our lab had earlier demonstrated the dysfunctional mitochondria in airway epithelium of the asthmatic mice lungs. Here, we show that Ku70 modulation by the administration of Ku70 plasmid attenuates asthma features and reduces mitochondrial dysfunction in the lungs of allergen exposed mice. Ku70 is a key DNA repair protein with diverse roles including VDJ recombination, telomere maintenance, and maintenance of cell homeostasis. Recently, we found a reduction in Ku70 expression in asthmatic airway epithelium, and this was associated with mitochondrial dysfunction in asthmatic condition. In this study, we have shown that Ku70 over-expression in asthmatic mice attenuated airway hyperresponsiveness, airway inflammation, sub-epithelial fibrosis along with reduction in TGF-β with no effect in IL-13 levels and goblet cell metaplasia. Ku70 over-expression in asthmatic mice reduced 8-isoprostane, a marker of oxidative stress, and restored the mitochondrial function in asthmatic mice. We further found these roles of Ku70 to be independent of DNA damage as Ku70 overexpressed mice did not show any reduction in DNA tail, an index of DNA damage. Thus, our findings indicate that Ku70 can attenuate crucial features of asthma along with the restoration of mitochondrial function. This implies that Ku70 could be a therapeutic target for asthma without affecting DNA repair function.

[Menthol enhances interleukin-13-induced synthesis and secretion of mucin 5AC in human bronchial epithelial cells]

OBJECTIVE

To investigate the effect of interleukin (IL) -13 combined with cold stimulation on synthesis and secretion of mucin (MUC) 5AC in human bronchial epithelial cell line 16HBE and explore the role of transient receptor potential 8 (TRPM8) and anti-apoptotic factor B-cell lymphoblast-2 (Bcl-2) in this process.

METHODS

16HBE cells were stimulated with 10 ng/mL IL-13, 1 mmol/L menthol, or both (1 mmol/L menthol was added after 6 days of IL-13 stimulation), and the changes in the expression of MUC5AC, intracellular Ca²⁺ concentration and Bcl-2 expression were evaluated. The effects of ABT-263 (a Bcl-2 inhibitor) and BCTC (a TRPM8 ion channel inhibitor), alone or in combination, on MUC5AC expression in the cells were tested, and the changes in intracellular Ca²⁺ and Bcl-2 expression following BCTC treatment were observed. The cell viability was assessed using CCK-8 assay, the mRNA expressions of MUC5AC and Bcl-2 were detected with real-time quantitative PCR, the level of MUC5AC in the culture medium was measured with ELISA, and the intracellular Ca²⁺ fluorescence intensity was determined with flow cytometry.

RESULTS

The mRNA and protein expressions of MUC5AC increased significantly in 16HBE cells following stimulation with IL-13, menthol, and both (P < 0.05), and were the highest in the combined treatment group with its peak level occurred at 24 h (P < 0.01). The intracellular Ca²⁺ fluorescence intensity and Bcl-2 mRNA expression were also increased in 16HBE cells after the stimulations (P < 0.05), and the increments were the most obvious in the combined treatment group (P < 0.01). Treatment with BCTC significantly lowered intracellular Ca²⁺ fluorescence intensity and the expressions of Bcl-2 and MUC5AC mRNA and protein in the cells stimulated with menthol or with both IL-13 and menthol (P < 0.05), but caused no significant changes in IL-13-stimulated cells (P > 0.05). Treatment with ABT-263 significantly lowered the mRNA and protein expressions of MUC5AC in the cells stimulated with IL-13 and menthol either alone or in combination (P < 0.05).

CONCLUSIONS

Menthol combined with IL-13 produces a synergistic effect to promote the synthesis and secretion of MUC5AC in 16HBE cells possibly by activating TRPM8 receptor to upregulate the expression of Bcl-2.

Comparative efficacy of glucocorticoid receptor agonists on Th2 cell function and attenuation by progesterone

BACKGROUND

Corticosteroids (CS)s suppress cytokine production and induce apoptosis of inflammatory cells. Prednisone and dexamethasone are oral CSs prescribed for treating asthma exacerbations. While prednisone is more commonly prescribed, dexamethasone is long acting and a more potent glucocorticoid receptor (GR) agonist. It can be administered as a one or two dose regime, unlike the five to seven days required for prednisone, a feature that increases compliance. We compared the relative ability of these two oral CSs to suppress type 2 inflammation. Since progesterone has affinity for the GR and women are more likely to relapse following an asthma exacerbation, we assessed its influence on CS action.

RESULTS

Dexamethasone suppressed the level of IL-5 and IL-13 mRNA within Th2 cells with ~ 10-fold higher potency than prednisolone (the active form of prednisone). Dexamethasone induced a higher proportion of apoptotic and dying cells than prednisolone, at all concentrations examined. Addition of progesterone reduced the capacity of both CS to drive cell death, though dexamethasone maintained significantly more killing activity. Progesterone blunted dexamethasone-induction of FKBP5 mRNA, indicating that the mechanism of action was by interference of the CS:GR complex.

CONCLUSIONS

Dexamethasone is both more potent and effective than prednisolone in suppressing type 2 cytokine levels and mediating apoptosis. Progesterone attenuated these anti-inflammatory effects, indicating its potential influence on CS responses in vivo. Collectively, our data suggest that when oral CS is required, dexamethasone may be better able to control type 2 inflammation, eliminate Th2 cells and ultimately lead to improved long-term outcomes. Further research in asthmatics is needed.

The Intriguing Role of Interleukin 13 in the Pathophysiology of Asthma

Approximately 5–10% of asthmatic patients worldwide suffer from severe asthma. Experimental and clinical studies have demonstrated that IL-13 is an important cytokine in chronic airways inflammation. IL-13 is involved in Th2 inflammation and has been identified as a possible therapeutic target in the treatment of asthma. Two different human monoclonal antibodies (mAbs) anti-IL-13 (tralokinumab and lebrikizumab) block binding and signaling of IL-13 to its receptors, IL-13Rα1 and IL-13Rα2. Several randomized, double-blind, placebo-controlled multicenter studies have evaluated the safety and efficacy of tralokinumab and lebrikizumab in the treatment of adult patients with severe asthma, but all have failed to meet their primary endpoints. No serious adverse events related to the treatment with these anti-IL-13 mAbs have been reported in these studies. These negative clinical results contrast with positive findings from blocking IL-13 signaling in experimental models of asthma, raising doubts about the transferrable value of some models. Interestingly, dupilumab, a mAb which blocks both IL-4 and IL-13 signaling reduces exacerbation rates and improves lung function in severe asthmatics. These results suggest that IL-4 and IL-13 share some, but not all functional activities in airway inflammation. Tralokinumab might show efficacy in a highly selected cohort of asthmatics characterized by overexpression of IL-13.

Novel Biological Therapies in Severe Asthma: Targeting the Right Trait

Asthma is a heterogeneous disease characterized by chronic airway inflammation that results in a wide spectrum of clinical manifestations. Patients with severe asthma represent a substantial share of consumption of healthcare resources and hospitalization. Moreover, these patients are at risk of increased morbidity and mortality. Recently, several phenotypes and endotypes of asthma have been identified. The identification of specific subtypes of asthma is fundamental for optimizing the clinical benefit of novel treatments. Although in most patients the disease can be controlled by some combination of pharmacologic agents, in some 5-10% of patients the disease remains uncontrolled. Several monoclonal antibodies (mAbs) targeting pathogenetic molecules (e.g., IgE, IL-5, IL- 5Rα, IL-4, IL-13, TSLP) are currently available or under development for the treatment of different forms of severe type 2 asthma. The identification of diagnostic and predictive biomarkers (e.g., IgE, blood eosinophil count, FeNO, periostin, etc.) has revolutioned the field of targeted therapy in severe asthma. Monoclonal antibodies targeting Th2-driven inflammation are generally safe in adult patients with moderate-to-severe asthma. The long-term safety of these biologics is a relevant issue that should be addressed. Unfortunately, little is known about non-type 2 asthma. Further studies are needed to identify biomarkers to guide targeted therapies of different forms of non-type 2 asthma.

Dupilumab in the treatment of asthma

Dupilumab is a fully human monoclonal IgG4 antibody that blocks IL-4 and IL-13 signaling. Its efficacy has been assessed across a range of atopic diseases, due to its ability to inhibit T helper cell 2 (Th2) mediated inflammation. It has already been approved in the USA and Europe for the treatment of atopic dermatitis. Recently, it also gained approval in the USA as add-on treatment for moderate-to-severe asthma in adolescents and adults. Phase II and III randomized controlled trials have demonstrated improvements in asthma exacerbation rates, FEV1, oral glucocorticoid use and a range of patient-reported outcomes, with a favorable safety profile. This article will review the available clinical trial data relating to the efficacy and safety of dupilumab in the management of asthma and related atopic respiratory conditions.

The Safety and Efficacy of Anti-IL-13 Treatment with Tralokinumab (CAT-354) in Moderate to Severe Asthma: A Systematic Review and Meta-Analysis

BACKGROUND

Several clinical studies have evaluated the use of tralokinumab (CAT-354) administration in patients with moderate to severe asthma; no consensus on tralokinumab efficacy and safety was reached. Thus, further analysis is required on the efficacy and safety of tralokinumab as an asthma biologic.

OBJECTIVE

To assess the efficacy and safety of subcutaneous injection of tralokinumab in patients with moderate to severe asthma.

METHODS

Clinical trials were identified from MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from their inception to November 4, 2018. Only randomized clinical trials (RCTs) with tralokinumab versus placebo treatment in patients with moderate to severe asthma were evaluated. Efficacy and safety outcomes were extracted, and a meta-analysis was performed using a random-effects model. The Cochrane Collaboration's risk-of-bias assessment tool was used to assess the risk of bias.

RESULTS

Five studies describing 6 RCTs (including 2928 adults with moderate to severe asthma) were pooled and analyzed in this study. Absolute FEV₁ was statistically improved in patients receiving tralokinumab at 300 mg every 2 weeks (mean difference [MD], 0.14 L; 95% CI, 0.08-0.21) and 600 mg every 2 weeks (MD, 0.20 L; 95% CI, 0.01-0.39), as well as FEV₁% changes (MD, 5.82%, 95% CI, 3.58-8.06, and MD, 11.8%, 95% CI, 0.79-22.81, respectively). Also, absolute forced vital capacity volume changes (MD, 0.11 L; 95% CI, 0.01-0.21) and percentage changes (MD, 4.44%; 95% CI, 0.84-8.04) improved in tralokinumab at 300 mg every 2 weeks. Asthma Quality of Life Questionnaire scores were not significantly different, and absolute Asthma Control Questionnaire 6 scores were statistically improved but did not reach the clinically meaningful difference. Tralokinumab treatment did not decrease annualized asthma exacerbation rate in unselected patients with moderate to severe asthma, but it was associated with improved annualized asthma exacerbation rate in patients with severe asthma with high fractional exhaled nitric oxide levels (rate ratio, 0.72; 95% CI, 0.53-0.97). Tralokinumab was not associated with an increased incidence of serious adverse events, but it did show an increase in mild injection-site reactions (odds ratio, 5.92; 95% CI, 1.61-21.76).

CONCLUSION

This pooled analysis of 6 RCTs suggested that tralokinumab was well tolerated and it modestly improved FEV₁ and forced vital capacity in patients with moderate to severe asthma. It did not render clinically important improvements in asthma-related quality of life, and nor did it reduce asthma exacerbations.

HSP90 inhibitor geldanamycin reverts IL-13- and IL-17-induced airway goblet cell metaplasia

Goblet cell metaplasia, a disabling hallmark of chronic lung disease, lacks curative treatments at present. To identify novel therapeutic targets for goblet cell metaplasia, we studied the transcriptional response profile of IL-13-exposed primary human airway epithelia in vitro and asthmatic airway epithelia in vivo. A perturbation-response profile connectivity approach identified geldanamycin, an inhibitor of heat shock protein 90 (HSP90) as a candidate therapeutic target. Our experiments confirmed that geldanamycin and other HSP90 inhibitors prevented IL-13-induced goblet cell metaplasia in vitro and in vivo. Geldanamycin also reverted established goblet cell metaplasia. Geldanamycin did not induce goblet cell death, nor did it solely block mucin synthesis or IL-13 receptor-proximal signaling. Geldanamycin affected the transcriptome of airway cells when exposed to IL-13, but not when exposed to vehicle. We hypothesized that the mechanism of action probably involves TGF-β, ERBB, or EHF, which would predict that geldanamycin would also revert IL-17-induced goblet cell metaplasia, a prediction confirmed by our experiments. Our findings suggest that persistent airway goblet cell metaplasia requires HSP90 activity and that HSP90 inhibitors will revert goblet cell metaplasia, despite active upstream inflammatory signaling. Moreover, HSP90 inhibitors may be a therapeutic option for airway diseases with goblet cell metaplasia of unknown mechanism.

A meta-analysis of anti-interleukin-13 monoclonal antibodies for uncontrolled asthma

More and more clinical trials have tried to assess the clinical benefit of anti-interleukin (IL)-13 monoclonal antibodies for uncontrolled asthma. The aim of this study is to evaluate the efficacy and safety of anti-IL-13 monoclonal antibodies for uncontrolled asthma. Major databases were searched for randomized controlled trials comparing the anti-IL-13 treatment and a placebo in uncontrolled asthma. Outcomes, including asthma exacerbation rate, forced expiratory volume in 1 second (FEV1), Asthma Quality of Life Questionnaire (AQLQ) scores, rescue medication use, and adverse events were extracted from included studies for systematic review and meta-analysis. Five studies involving 3476 patients and two anti-IL-13 antibodies (lebrikizumab and tralokinumab) were included in this meta-analysis. Compared to the placebo, anti-IL-13 treatments were associated with significant improvement in asthma exacerbation, FEV1 and AQLQ scores, and reduction in rescue medication use. Adverse events and serious adverse events were similar between two groups. Subgroup analysis showed patients with high periostin level had a lower risk of asthma exacerbation after receiving anti-IL-13 treatment. Our study suggests that anti-IL-13 monoclonal antibodies could improve the management of uncontrolled asthma. Periostin may be a good biomarker to detect the specific subgroup who could get better response to anti-IL-13 treatments. In view of blocking IL-13 alone is possibly not enough to achieve asthma control because of the overlapping pathophysiological roles of IL-13/IL-4 in inflammatory pathways, combined blocking of IL-13 and IL-4 with monoclonal antibodies may be more encouraging.

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.

Tralokinumab for the treatment of severe, uncontrolled asthma: the ATMOSPHERE clinical development program

Tralokinumab, a fully human IgG₄ monoclonal antibody, specifically neutralizes IL-13. The ATMOSPHERE clinical development program comprised four randomized, placebo-controlled clinical trials and an open-label study that aimed to assess the efficacy and safety of tralokinumab for the treatment of severe, uncontrolled asthma. The two pivotal trials (STRATOS 1 and STRATOS 2; NCT02161757 and NCT02194699) evaluated the efficacy and safety of tralokinumab, with STRATOS 1 identifying a subgroup most likely to demonstrate enhanced response to treatment. Further trials have assessed the ability of tralokinumab to reduce oral corticosteroid use (TROPOS; NCT02281357) and determined its mechanistic effects (MESOS; NCT02449473). An open-label study in Japanese individuals (NCT02902809) assessed the long-term safety and tolerability of tralokinumab in this population.

Interferon-gamma deficiency protects against aging-related goblet cell loss

Aging is a well-recognized risk factor for dry eye. Interferon-gamma (IFN-γ) has been implicated in conjunctival keratinization and goblet cell loss in dry eye. We investigated the role of IFN-γ in age-related dry eye by evaluating young (8 weeks) and aged (15 months; 15M) C57BL/6 (B6) and IFN-γKO mice. Age effects on the conjunctiva and cornea epithelium were assessed with PAS staining and corneal staining, respectively. Expression of T cell-related cytokines (IL-17A, IFN-γ), chemokines (CXCL10 and CCL20), in the ocular surface epithelium was evaluated by real time PCR. A significant decrease in filled goblet cells was noted in 15M B6 mice and this was significantly lower than age and sex-matched IFN-γKO mice. Aged male B6 had significantly higher IFN-γ, and CXCL10 mRNA in their conjunctiva than female B6 mice. Aged IFN-γKO females had significantly higher IL-17A mRNA in conjunctiva than IFN-γKO males and B6 mice. Corneal barrier dysfunction was observed in 15M female B6 and aged IFN-γKO mice of both sexes; however it was significantly higher in IFN-γKO compared to B6 mice. While there was a significant increase in IL 17A, and CCL20 in corneas of aged female B6 and IFN-γKO mice compared to males, these changes were more evident in aged female IFN-γKO group.

Partial resistance of IFN-γKO mice to aging-induced goblet cell loss indicates IFN-γ is involved in the age-related decline in conjunctival goblet cells. Increased corneal IL-17A expression paralleled corneal barrier disruption in aging female of both strains. IFN-γ appears to suppress IL-17A on the ocular surface.

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.

Corticosteroid and long-acting ß-agonist therapy reduces epithelial goblet cell metaplasia

BACKGROUND

Bronchial epithelial goblet cell metaplasia (GCM) with hyperplasia is a prominent feature of asthma, but the effects of treatment with corticosteroids alone or in combination with a long-acting β₂ -adrenergic receptor agonist (LABA) on GCM in the bronchial epithelium are unknown.

OBJECTIVES

To determine whether corticosteroid alone or in combination with a LABA alters protein and gene expression pathways associated with IL-13-induced goblet cell metaplasia.

RESULTS

We evaluated the effects of fluticasone propionate (FP) and of salmeterol (SM), on the response of well-differentiated cultured bronchial epithelial cells to interleukin-13 (IL-13). Outcome measures included gene expression of SPDEF/FOXa2, gene expression and protein production of MUC5AC/MUC5B and morphologic appearance of cultured epithelial cell sheets. We additionally analysed expression of these genes in bronchial epithelial brushings from healthy, steroid-naïve asthmatic and steroid-treated asthmatic subjects. In cultured airway epithelial cells, FP treatment inhibited IL-13-induced suppression of FOXa2 gene expression and up-regulation of SPDEF, alterations in gene and protein measures of MUC5AC and MUC5B and induction of GCM. The addition of SM synergistically modified the effects of FP modestly-only for gel-forming mucin MUC5AC. In bronchial epithelial cells recovered from asthmatic vs healthy human subjects, we found FOXa2 and MUC5B gene expression to be reduced and SPDEF and MUC5AC gene expression to be increased; these alterations were not observed in bronchial epithelial cells recovered after treatment with inhaled corticosteroids.

CONCLUSION AND CLINICAL RELEVANCE

Corticosteroid treatment inhibits IL-13-induced GCM of the airways in asthma, possibly through its effects on SPDEF and FOXa2 regulation of mucin gene expression. These effects are modestly augmented by the addition of a long-acting ß-agonist. As we found evidence for drug treatment counteracting the effects of IL-13 on the epithelium, we conclude that further exploration into the mechanisms by which corticosteroids and long-acting β₂ -adrenergic agonists confer protection against pathologic airway changes is warranted.

Role of IFN-γ, IL-13, and IL-17 on mucociliary differentiation of nasal epithelial cells in chronic rhinosinusitis with nasal polyps

BACKGROUND

Mucociliary dysfunction is a prominent pathophysiological feature of chronic rhinosinusitis with nasal polyps (CRSwNP); however, the precise mechanisms underlying mucociliary dysfunction are still unclear.

OBJECTIVE

The aim of this study was therefore to evaluate the effects of IFN-γ, IL-13, and IL-17 on human nasal mucociliary differentiation and ciliary beat frequency (CBF) in patients with CRSwNP.

METHODS

Human nasal epithelial cells from tissue of patients with CRSwNP and control subjects were established as air-liquid interface (ALI) primary cultures. Confluent cultures were incubated with10 ng/mL each of IFN-γ, IL-13, or IL-17 for 14 days and assessed for expression of specific morphological markers and factors associated with mucociliary differentiation, the percentage of ciliated and goblet cells, and CBF.

RESULTS

In comparison with control subjects, percentage of ciliated cells and CBF were decreased; while percentage of goblet cells, FOXJ1, and MUC5AC mRNA expression were increased in nasal polyp-derived epithelial cultures. Treatment with IFN-γ and IL-13 significantly decreased the expression of β-tubulin IV (specific cilia marker), ciliated cell number, and expression of FOXJ1 and DNAI2, in epithelial cultures derived from both CRSwNP patients and control subjects. Furthermore, while both IFN-γ and IL-13 treatment significantly decreased the CBF of cells from both CRSwNP patients and control subjects, IL-13 additionally significantly increased goblet cell number and the expression of MUC5AC and CLCA1, in these cultures. IL-17 treatment did not significantly affect ciliated or goblet cell differentiation, CBF, nor MUC5AC and CLCA1 expression, but increased both MUC5B mRNA and protein expression in these cultures.

CONCLUSION AND CLINICAL RELEVANCE

The demonstration that IFN-γ and IL-13 both significantly reduce ciliated cell differentiation and CBF in CRSwNP patients, and IL-13 additionally induces significant goblet cell hyperplasia and MUC5AC mucin expression, as well as IL-17 significantly increases MUC5B mucin expression, suggests that these inflammatory cytokines may be potential therapeutic targets in the management of CRSwNP.

Inhalation of inactivated‑Mycobacterium phlei prevents asthma‑mediated airway hyperresponsiveness and airway eosinophilia in mice by reducing IL‑5 and IL‑13 levels

The present study aimed to investigate whether inhalation of inactivated‑Mycobacterium phlei could prevent airway hyperresponsiveness and airway eosinophilia. A total of 24 male Balb/c mice were randomly divided into three groups: Normal control group (group A), asthma model group (group B) and the intervention group (group C), (8 mice/group). Group A mice were sensitized and with challenged saline and group B with ovalbumin (OVA). Group C mice were administered with aerosol Mycobacterium phlei once daily prior to the allergen challenge. Airway responsiveness in each group was assessed. All the animals were sacrificed and lung tissues, blood samples and bronchoalveolar lavage fluid (BALF) were harvested. Cell fractionation and differential cells were counted in serum and BALF. HE staining and alcian blue/periodic acid Schiff staining were used to measure airway eosinophilic inflammation and mucus production. The levels of the cytokines IL‑5, IL‑13 and IgE were measured in lung and BALF as determined by ELISA and reverse transcription‑quantitative polymerase chain reaction assays. The results indicated that inactivated‑Mycobacterium phlei suppressed the airway hyperresponsiveness and mitigated airway eosinophilia induced by a methacholine challenge, and significantly reduced the levels of cytokines IL‑5 and IL‑13 in lung tissue and IgE level in BALF when compared with the OVA‑sensitized mice. In conclusion, inhalation of inactivated‑Mycobacterium phlei could reduce OVA‑induced airway hyperresponsiveness and may be a potential alternative therapy for allergic airway diseases.

A Critical Evaluation of Anti-IL-13 and Anti-IL-4 Strategies in Severe Asthma

Asthma is a high-prevalence disease, still accounting for mortality and high direct and indirect costs. It is now recognized that, despite the implementation of guidelines, a large proportion of cases remain not controlled. Certainly, adherence to therapy and the education of patients remain the primary objective, but the increasingly detailed knowledge about the pathogenic mechanisms and new biotechnologies offer the opportunity to better address and treat the disease. Interleukin (IL)-13 and IL-4 appear as the most suitable targets to treat the T helper 2 (TH2)-mediated forms (endotypes) of asthma. IL-13 and IL-4 partly share the same receptor and signaling pathways and both are deeply involved in immunoglobulin E (IgE) synthesis, eosinophil activation, mucus secretion and airways remodeling. Several anti-IL-13 strategies have been proposed (anrukinzumab, lebrikizunab and tralokinumab), with relevant clinical results reported with lebrikizumab. Such studies facilitate better definition of the possible predictive markers of response to a specific treatment (e.g. eosinophils, total IgE, fraction of exhaled nitric oxide and periostin). In parallel, anti-IL-4 strategies have been attempted (pascolizumab, pitakinra and dupilumab). So far, dupilumab was reported capable of reducing the severity of asthma and the rate of exacerbations. IL-13 and IL-4 are crucial in TH2-mediated inflammation in asthma, but it remains clear that only specific endotypes respond to these treatments. Although the use of anti-IL-14 and anti-IL-13 strategies is promising, the search for appropriate predictive biomarkers is urgently needed to better apply biological treatments.

Efficacy and safety of tralokinumab in patients with severe uncontrolled asthma: a randomised, double-blind, placebo-controlled, phase 2b trial

BACKGROUND

Interleukin 13 is a central mediator of asthma. Tralokinumab is a human interleukin-13 neutralising monoclonal antibody. We aimed to assess the efficacy and safety of two dosing regimens of tralokinumab in patients with severe uncontrolled asthma.

METHODS

We did a randomised, double-blind, placebo-controlled, parallel-group, multicentre, phase 2b study at 98 sites in North America, South America, Europe, and Asia. Patients aged 18-75 years with severe asthma and two to six exacerbations in the previous year were randomly assigned (1:1), via an interactive voice-response or web-response system, to one of two dosing regimen groups (every 2 weeks, or every 2 weeks for 12 weeks then every 4 weeks) and further randomised (2:1), via computer-generated permuted-block randomisation (block size of six), to receive tralokinumab 300 mg or placebo for 1 year. All participants received high-dose fluticasone and salmeterol and continued other pre-study controller drugs. Treatment was administered by an unmasked study investigator not involved in the management of patients; all other study site personnel, patients, the study funder, and data analysts were masked to treatment allocation. The primary endpoint was the annual asthma exacerbation rate at week 52 in the intention-to-treat population. Key secondary endpoints included prebronchodilator forced expiratory volume in 1 s (FEV1), Asthma Control Questionnaire-6 (ACQ-6), and Asthma Quality of Life Questionnaire-Standardised Version (AQLQ[S]). This trial is registered with ClinicalTrials.gov, number NCT01402986.

FINDINGS

Between Oct 4, 2011, and Feb 22, 2014, we randomly assigned 452 patients to receive placebo (n=151) or tralokinumab every 2 weeks (n=150) or every 4 weeks (n=151), of whom 383 (85%) completed the treatment period up to week 52. The annual asthma exacerbation rate at week 52 was similar between patients receiving tralokinumab every 2 weeks (0.91 per patient per year [95% CI 0.76-1.08]) and every 4 weeks (0.97 [0.81-1.14]), and those receiving placebo (0.90 [0.75-1.08]). At week 52, percentage changes in annual asthma exacerbation rate were not significant with tralokinumab every 2 weeks or every 4 weeks versus placebo (6% [95% CI -31 to 33; p=0.709] and -2% [-46 to 29; p=0.904], respectively), with positive changes showing a decrease in exacerbation rate and negative changes showing an increase. Prebronchodilator FEV1 was significantly increased compared with placebo for tralokinumab every 2 weeks (change from baseline 7.3% [95% CI 2.6-12.0]; p=0.003), but not every 4 weeks (1.8% [-2.9 to 6.6]; p=0.448); however, we did not identify significant changes in the other key secondary endpoints. In a post-hoc subgroup analysis of patients not on long-term oral corticosteroids and with baseline FEV1 reversibility of 12% or greater, we noted a non-significant improvement in asthma exacerbation rate (44% [95% CI -22 to 74]; p=0.147) and significant improvements in key secondary endpoints (FEV1 12.2% [1.7-22.7]; p=0.022; ACQ-6 -0.55 [-1.07 to -0.04]; p=0.036; and AQLQ[S] 0.70 [0.12-1.28]; p=0.019) in patients given tralokinumab every 2 weeks (n=33) compared with placebo (n=48). In patients in this subgroup who also had baseline serum dipeptidyl peptidase-4 (DPP-4) higher than the population baseline median, we noted additional improvements in prebronchodilator FEV1, ACQ-6, and AQLQ(S), and, in those with periostin concentrations higher than the median, we noted improvements in asthma exacerbation rate, prebronchodilator FEV1, and ACQ-6. The incidence of treatment-emergent adverse events was similar between the tralokinumab and placebo groups. Treatment-emergent serious adverse events regarded as related to the study drug were pneumonia (one [1%] patient in the placebo group), pneumococcal pneumonia (one [1%] in the tralokinumab every 2 weeks group), angioedema (one [1%] in the placebo group), and worsening asthma (one [1%] in the tralokinumab every 2 weeks group and two [1%] in the tralokinumab every 4 weeks group).

INTERPRETATION

In this phase 2b study, both tralokinumab regimens had an acceptable safety and tolerability profile but did not significantly reduce asthma exacerbation rates in patients with severe uncontrolled asthma. Improvement in FEV1 with tralokinumab given every 2 weeks and results of post-hoc subgroup analyses suggested a possible treatment effect in a defined population of patients with severe uncontrolled asthma. This effect is being further investigated in ongoing phase 3 trials, along with the potential utility of DPP-4 and periostin as biomarkers of interleukin-13 pathway activation.

FUNDING

MedImmune.

IL-13 Stimulates Proliferation and Expression of Mucin and Immunomodulatory Genes in Cultured Conjunctival Goblet Cells

PURPOSE

To investigate the effects of IL-13 on goblet cell proliferation, differentiation, and expression of mucin and immunomodulatory genes.

METHODS

Explants were excised from the conjunctiva of young C57BL/6 mice. Cultures received 200 μL per week of either Keratinocyte media (KSFM) or KSFM supplemented with 10 ng/mL IL-13 and were incubated for 3 (D3), 7 (D7), or 14 (D14) days. Subsequently, cell proliferation was assessed or cultures were immunostained, collected for dot blot, or for reverse transcription (RT) and quantitative real-time PCR (qPCR) or for RT-PCR gene array.

RESULTS

The cultured conjunctival epithelium expressed goblet cell associated keratin 7 and mucins MUC5AC and MUC2 and when stimulated with IL-13 showed increased proliferation at D3 and D7 (P < 0.05) compared with control. MUC5AC expression was increased in the IL-13-treated group at D3 and D14 (P < 0.05). IL-13-treated cultures showed increased chemokine ligand 26 (CCL26), chloride channel calcium activated channel 3 (CLCA3), fas ligand (FasL), and Relm-β at D7. All conjunctival cultures expressed MUC2, and its expression was decreased at D3 (P < 0.05) and increased at D14 (P < 0.05) with IL-13 treatment.

CONCLUSIONS

This study demonstrated that conjunctival goblet cells are IL-13 responsive cells that produce factors known to maintain epithelial barrier, stimulate mucin production, and modulate immune response in nonocular mucosa when treated with IL-13. The functional significance of IL-13-stimulated factors remains to be determined.

Altered balance of interleukin-13/interferon-gamma contributes to lacrimal gland destruction and secretory dysfunction in CD25 knockout model of Sjögren's syndrome

Introduction

The lacrimal gland (LG) of the CD25^-/^- model of Sjögren’s syndrome (SS) has high interleukin (IL)-17, IL-13 and interferon-gamma (IFN-γ) cytokines. The specific contribution of these cytokines to the onset and severity of dacryoadenitis in the CD25^-/^- mice has not been evaluated.

Methods

CD25⁻/⁻IL-17A⁻/⁻, CD25⁻/⁻IL-17⁻/⁻IFN-γ⁻/⁻ and CD25⁻/⁻IFN-γ⁻/⁻ were used at 4, 8, 12, 16 weeks (W). Total lymphocytic infiltration was evaluated by histology and characterized by flow cytometry. Epidermal growth factor (EGF) concentration was measured in tears. Immunofluorescent staining evaluated expression of IFN-γ receptor (IFN-γR) and apoptosis. Real-time PCR evaluated inflammatory and T cell-related cytokines expression in LG. Caspase-3, -8, -9 activities was assayed in LG lysates. T helper cytokines were measured in serum by Luminex assay.

Results

The greatest total LG infiltration at 8 W was seen in CD25⁻/⁻IL-17A⁻/⁻ (95%), followed by CD25⁻/⁻ (71%) and IL-17⁻/⁻ (12%). Tear EGF concentration was in normal range in CD25⁻/⁻ at 4 W and in very low levels in both CD25⁻/⁻ and CD25⁻/⁻IL-17A⁻/⁻. CD25⁻/⁻ had high levels of inflammatory cytokines transcripts in LG compared to IL-17⁻/⁻ mice; however, CD25⁻/⁻IL-17A⁻/⁻ had even higher IL-1β, IFN-γR, caspase-3, -8, -9 mRNA levels, greater immunoreactivity to IFN-γR in LG acini, greater number of apoptotic⁺ cells and greater caspases activities in the LG at 8 W. CD25⁻/⁻IL-17A⁻/⁻ had lower IL-13 concentration and lower IL-13/IFN-γ ratio compared to CD25⁻/⁻ in serum. CD25⁻/⁻IFN-γ⁻/⁻ had lower number of apoptotic⁺ cells and decreased caspase-3 expression in LG. CD25⁻/⁻IL-17⁻/⁻IFN-γ⁻/⁻ had lower total lymphocytic cell infiltration at 8 W (48%), CD4⁺T cell infiltration and expression of IFN-γR and apoptotic⁺ cells in the LG and increased tear EGF concentration in tears.

Conclusions

IFN-γ is critical for LG destruction and secretory dysfunction in the CD25⁻/⁻ model of SS. Altered balance between IFN-γ and IL-13 in the CD25⁻/⁻IL-17A⁻/⁻ mice accelerates LG destruction by increasing glandular apoptosis and facilitating apoptosis through increased expression of IFN-γR by glandular epithelium and activation of caspases. Targeting both IFN-γ and IL-17 may be beneficial for treating the LG inflammation in SS.

TMEM16A-Mediated Mucin Secretion in IL-13-Induced Nasal Epithelial Cells From Chronic Rhinosinusitis Patients

Purpose

Chronic rhinosinusitis with nasal polyps (CRSwNP), a mainly Th2 cytokine-mediated disease, often involves mucus secretion. Recent evidence suggests that transmembrane protein 16A (TMEM16A), a calcium-activated Cl^- channel (CaCC), can regulate mucus secretion from airway epithelium by transepithelial electrolyte transport and hydration. However, the role of TMEM16A in mucin production/secretion in the airway epithelium is not clear. This study was conducted to determine the role of TMEM16A in mediating mucin secretion in human nasal polyp epithelial cells (HNPECs) induced by IL-13.

Methods

Human sinonasal mucosa tissue and dissociated sinonasal epithelium from control subjects and patients with CRSwNP were assessed for the expression of TMEM16A and the secretion of human mucin 5AC (MUC5AC) by immunohistochemistry, Western blot analysis, and enzyme-linked immuno-sorbent assay (ELISA). A model of the Th2 inflammatory environment was created by exposure of primary air-liquid interface (ALI)-cultured HNPECs to interleukin-13 (IL-13) for 14 days, with subsequent assessment of TMEM16A expression in cell lysates by Western blotting and MUC5AC secretion in apical washings of cells by ELISA.

Results

The expressions of TMEM16A and MUC5AC were increased in human nasal polyp tissue and dissociated nasal polyp epithelium. TMEM16A was detected in IL-13-treated HNPECs, specifically in MUC5AC-positive cells but not in ciliated cells. IL-13 treatment increased percentages of TMEM16A-positive cells, MUC5AC-positive cells, and cells coexpressing TMEM16A/MUC5AC, the expression of TMEM16A protein, and the secretion of MUC5AC. T16Ainh-A01, a TMEM16A inhibitor, attenuated these IL-13-induced effects.

Conclusions

The expression of TMEM16A and MUC5AC are increased in CRSwNP, which might be a direct effect of Th2 cytokines present in the sinonasal mucosa in CRSwNP. Down-regulation of TMEM16A expression and MUC5AC secretion in HNPECs by T16Ainh-A01 indicates that TMEM16A might play an important role in mucin secretion in upper airway inflammatory diseases.

The effects of concomitant GERD, dyspepsia, and rhinosinusitis on asthma symptoms and FeNO in asthmatic patients taking controller medications

Background

Losing the sense of smell, which suggests eosinophilic rhinosinusitis, is a subjective symptom, sometimes reported in asthmatic patients taking controller medication. Upper abdominal symptoms, suggesting gastroesophageal reflux disease (GERD) or functional dyspepsia, occur also in these patients. However, the relationship between these symptoms, concomitant with asthma, and the intensity of eosinophilic airway inflammation remains obscure.

Objective

To assess the symptoms of asthma and rhinosinusitis, and to examine the relationship between the symptoms and bronchial inflammation, a new questionnaire, the G scale, was developed. To investigate the effects of GERD, dyspepsia, and rhinosinusitis on asthma symptoms and bronchial inflammation, the symptoms of asthma and rhinosinusitis obtained by the G scale, upper abdominal symptoms obtained by the modified F scale, a questionnaire for GERD and dyspepsia, and fractional exhaled nitric oxide (FeNO) were analyzed.

Methods

A prospective, observational study was performed in four hospitals in Gunma prefecture, and a retrospective analysis was done using data obtained from five hospitals in Gunma prefecture and Fukui prefecture, Japan. A total of 252 patients diagnosed as having asthma participated in the prospective study.

Results

The frequency of daytime phlegm or losing the sense of smell had a positive correlation with FeNO levels in asthmatic patients taking controller medication. Upper abdominal symptoms, as well as symptoms suggesting rhinitis, were well correlated with asthma symptoms. However, neither upper abdominal symptoms nor rhinitis symptoms increased FeNO levels, which reflect eosinophilic airway inflammation during treatment for asthma. On the other hand, the degree of upper abdominal symptoms or dyspepsia symptoms had a weak but significant negative correlation with FeNO levels.

Conclusion

Daytime phlegm and losing the sense of smell suggest that eosinophilic airway inflammation persists, despite anti-inflammatory therapy, in patients with asthma. Although rhinitis and GERD made the subjective symptoms of asthma worse, they did not seem to enhance eosinophilic airway inflammation.

Reconstituted human upper airway epithelium as 3-d in vitro model for nasal polyposis

Background

Primary human airway epithelial cells cultured in an air-liquid interface (ALI) develop a well-differentiated epithelium. However, neither characterization of mucociliar differentiation overtime nor the inflammatory function of reconstituted nasal polyp (NP) epithelia have been described.

Objectives

1^st) To develop and characterize the mucociliar differentiation overtime of human epithelial cells of chronic rhinosinusitis with nasal polyps (CRSwNP) in ALI culture system; 2^nd) To corroborate that 3D in vitro model of NP reconstituted epithelium maintains, compared to control nasal mucosa (NM), an inflammatory function.

Methods

Epithelial cells were obtained from 9 NP and 7 control NM, and differentiated in ALI culture for 28 days. Mucociliary differentiation was characterized at different times (0, 7, 14, 21, and 28 days) using ultrastructure analysis by electron microscopy; ΔNp63 (basal stem/progenitor cell), β-tubulin IV (cilia), and MUC5AC (goblet cell) expression by immunocytochemistry; and mucous (MUC5AC, MUC5B) and serous (Lactoferrin) secretion by ELISA. Inflammatory function of ALI cultures (at days 0, 14, and 28) through cytokine (IL-8, IL-1β, IL-6, IL-10, TNF-α, and IL-12p70) and chemokine (RANTES, MIG, MCP-1, IP-10, eotaxin-1, and GM-CSF) production was analysed by CBA (Cytometric Bead Array).

Results

In both NP and control NM ALI cultures, pseudostratified epithelium with ciliated, mucus-secreting, and basal cells were observed by electron microscopy at days 14 and 28. Displaying epithelial cell re-differentation, β-tubulin IV and MUC5AC positive cells increased, while ΔNp63 positive cells decreased overtime. No significant differences were found overtime in MUC5AC, MUC5B, and lactoferrin secretions between both ALI cultures. IL-8 and GM-CSF were significantly increased in NP compared to control NM regenerated epithelia.

Conclusion

Reconstituted epithelia from human NP epithelial cells cultured in ALI system provides a 3D in vitro model that could be useful both for studying the role of epithelium in CRSwNP while developing new therapeutic strategies, including cell therapy, for CRSwNP.

Mucociliary clearance: pathophysiological aspects

Mucociliary clearance has long been known to be a significant innate defence mechanism against inhaled microbes and irritants. Important knowledge has been gathered regarding the anatomy and physiology of this system, and in recent years, extensive studies of the pathophysiology related to lung diseases characterized by defective mucus clearance have resulted in a variety of therapies, which might be able to enhance clearance from the lungs. In addition, ways to study in vivo mucociliary clearance in humans have been developed. This can be used as a means to assess the effect of different pharmacological interventions on clearance rate, to study the importance of defective mucus clearance in different lung diseases or as a diagnostic tool in the work-up of patients with recurrent airway diseases. The aim of this review is to provide an overview of the anatomy, physiology, pathophysiology, and clinical aspects of mucociliary clearance and to present a clinically applicable test that can be used for in vivo assessment of mucociliary clearance in patients. In addition, the reader will be presented with a protocol for this test, which has been validated and used as a diagnostic routine tool in the work-up of patients suspected for primary ciliary dyskinesia at Rigshospitalet, Denmark for over a decade.

Oxidized PLs and vascular inflammation

Oxidized PLs (OxPLs) generated in health and disease are now recognized as important mediators of cellular signalling. There is an increasing body of evidence showing that PL peroxidation is not only increased in vascular disorders, but is also a physiological event of relevance to coagulation, innate immunity, and self-tolerance. Nonenzymatically formed OxPLs generated during chronic inflammation is an uncontrolled event, generating hundreds of diverse structures, and prone to more deleterious bioactivities. In contrast, enzymatic formation of OxPLs is tightly regulated, involving receptors and intracellular signaling, acting as part of the normal physiological response to injury in order to restore homeostasis. In the present review, the major nonenzymatic OxPLs structures found during vascular inflammation are summarized, along with a brief description of their known biological activities. Also, we review what is currently known about enzymatic formation of OxPLs by acutely activated immune cells and their signaling actions under homeostatic and pathological conditions.

Cross-roads in the lung: immune cells and tissue interactions as determinants of allergic asthma

Allergic asthma is a chronic disease of the lung characterized by underlying Th2- and IgE-mediated inflammation, structural alterations of the bronchial wall, and airway hyperresponsiveness. Initial allergic sensitization and later development of chronic disease are determined by close interactions between lung structural cells and the resident and migratory immune cells in the lung. Epithelial cells play a crucial role in allergic sensitization by directly influencing dendritic cells induction of tolerant or effector T cells and production of type 2 cytokines by innate immune cells. During chronic disease, the bronchial epithelium, stroma, and smooth muscle become structurally and functionally altered, contributing to the perpetuation of tissue remodeling. Thus, targeting tissue-driven pathology in addition to inflammation may increase the effectiveness of asthma treatment.

IL-31 does not induce normal human ciliated epithelial cells to differentiate into a phenotype consistent with the pathophysiology of asthma

BACKGROUND

IL-31 is a novel cytokine that has been implicated in allergic diseases such as atopic dermatitis and more recently asthma. While IL-31 has been well studied in skin conditions such as atopic dermatitis, little is known about the role IL-31 plays in asthma and specifically the differentiation process of the bronchial epithelium, which is central to the pathogenesis of allergic asthma.

METHODS

We examined the effects of IL-13 (20 ng/ml), IL-31 (20 ng/ml) and an IL-13/IL-31 combination stimulation (20 ng/ml each) on the in vitro mucociliary differentiation of paediatric bronchial epithelial cells (PBECs) from healthy patients (n=6). IL-31 receptor (IL-31-RA) expression, markers of differentiation (goblet and ciliated cells), transepithelial electrical resistance (TEER), quantification of goblet and ciliated cells, real time PCR for MUC5AC, ELISA for VEGF, EGF and MCP-1 (CCL-2) and ELISA for MUC5AC were assessed.

RESULTS

We found that well-differentiated PBECs expressed IL-31-RA however it's expression did not increase upon stimulation with IL-31 or either of the other treatments. TEER indicated good formation of tight junctions which was found to be similar across all treatment groups (p=0.9). We found that IL-13 alone significantly reduced the number of ciliated cells compared with unstimulated (IL-13 stimuation: mean=4.8% (SD=2.5); unstimulated: mean=15.9%, (SD=7.4), p<0.01). IL-31 stimulation alone had no effect on ciliated cells whereas the IL-13/IL-31 combination stimulation significantly reduced the number of ciliated cells compared with control (IL-13/IL-31 combination: mean=5.1% (SD=4.6); unstimulated: mean=15.9%, (SD=7.4), p<0.01). We did not find that the combination of IL-13 and IL-31 had any additional effects to that of IL-13 alone. MUC5AC mRNA and secreted mucin was found in similar levels between unstimulated and all treatments, however IL-13 increased levels of MUC5AC mRNA by a factor of 2.84, albeit not significantly, compared with unstimulated cultures (IL-13 stimulation: mean=2.84 (SD=3.79); unstimulated: mean=1.0).

CONCLUSIONS

IL-31RA receptor is present on well-differentiated paediatric bronchial epithelial cells. IL-31 does not exhibit any detrimental effects on mucociliary differentiation. IL-31 does not appear to have a synergistic effect when combined in culture with IL-13, in the differentiation process.

Lack of IL-4 receptor expression on T helper cells reduces T helper 2 cell polyfunctionality and confers resistance in allergic bronchopulmonary mycosis

T helper (Th)1 and Th2 cells play decisive roles in the regulation of resistance vs. susceptibility to pulmonary cryptococcosis. To study the function of interleukin (IL)-4 receptor (IL-4R) on Th cells in pulmonary cryptococcosis, we infected mice specifically lacking IL-4Rα on CD4(+) T cells (Lck(Cre)IL-4Rα(-/lox) mice) and IL-4Rα(-/lox) controls. Lck(Cre)IL-4Rα(-/lox) mice developed enhanced resistance accompanied by reduced pulmonary allergic inflammation and diminished production of the Th2 cytokines IL-4, IL-5, and IL-13 as compared with IL-4Rα(-/lox) mice. Polyfunctional antigen-specific Th2 cells producing simultaneously two or three Th2 cytokines were reduced in infected Lck(Cre)IL-4Rα(-/lox) mice, pointing to a critical role of polyfunctional Th2 cells for disease progression. Reduced Th2 polyfunctionality was associated with fewer pulmonary alternatively activated macrophages. This work is the first direct evidence for a critical contribution of the IL-4R on Th cells to Th2-dependent susceptibility during allergic bronchopulmonary mycosis. Moreover, the data demonstrate that the quality of the Th2 response has an impact on type 2 inflammation. The analysis of polyfunctional Th2 cells may be useful for monitoring the course of the disease.

Esterified eicosanoids: generation, characterization and function

Eicosanoids are oxidation products of C20 polyunsaturated fatty acids (e.g. arachidonic acid) that include prostaglandins, thromboxanes, leukotrienes and hydroperoxy fatty acids. They have important biological roles in vivo, including regulation of renal, cardiovascular and gastrointestinal function. Historically, eicosanoids were thought to mediate their signaling actions exclusively as free acids, however evidence is now emerging that they may also be generated attached to other functional groups including phospholipids and glycerol, and that these more complex forms are pathophysiological signaling mediators in their own right. Early studies showed that exogenously added eicosanoids could become esterified into membrane phospholipids of cells, while more recently, it was uncovered that esterified eicosanoids are formed endogenously. This review summarizes our current knowledge of this area, starting with the early discoveries documenting what is known about eicosanoid generation and their esterification, and moving on to discuss the discovery that esterified eicosanoids are generated endogenously by a number of different cell types. Recent research that is highlighting new structures and functions of these important lipid mediators will be presented. This article is part of a Special Issue entitled: Oxidized phospholipids-their properties and interactions with proteins.

Effect of dexamethasone on wound healing of the septal mucosa in the rat

BACKGROUND

Postoperative treatment after functional endoscopic sinus surgery (FESS) aims to modulate the wound healing process. Systemic or topically applied corticosteroids have been reported to be beneficial for improving nasal wound healing after FESS. However, few studies have investigated the effects of postoperative systemic steroids on nasal wound healing with regard to histological changes. The aim of this study was to evaluate the effect of systemic dexamethasone on nasal wound healing after mechanical injury in the rat.

METHODS

A unilateral wound in the nasal cavity was induced using the brushing technique in 4-week-old, Sprague-Dawley rats (n = 70). Dexamethasone (0.15 mg/kg daily for 7 days) and normal saline were administered i.p. to the experimental and control groups (n = 35 for each) after the injury. The rats (n = 7 for each) were killed on days 2, 5, 14, 28, and 42 after the injury. Histological changes in the nasal mucosa were examined and compared using hematoxylin and eosin and Masson's trichrome staining.

RESULTS

The experimental group showed less subepithelial edema formation and epithelial disarray at the early phase of the wound healing period. There were statistically significant differences in the subepithelial thickness and epithelial thickness indices between the experimental and control groups (p < 0.05). Ciliary and goblet cell indices were lower in the experimental group, which means that ciliary and goblet cell regeneration may be delayed by dexamethasone (p < 0.05). There were no differences in the subepithelial fibrosis index between the two groups. Adhesion formation between the nasal septum and turbinate were found only in the control group.

CONCLUSION

Systemic dexamethasone after mucosal injury may lessen subepithelial edema, goblet cell hyperplasia, and adhesion formation; however, it may cause delayed mucosal ciliary regeneration.

Homeostatic control of conjunctival mucosal goblet cells by NKT-derived IL-13

Although the effects of the interleukin 13 (IL-13) on goblet cell (GC) hyperplasia have been studied in the gut and respiratory tracts, its effect on regulating conjunctival GC has not been explored. The purpose of this study was to determine the major IL-13-producing cell type and the role of IL-13 in GC homeostasis in normal murine conjunctiva. Using isolating techniques, we identified natural killer (NK)/natural killer T (NKT) cells as the main producers of IL-13. We also observed that IL-13 knockout (KO) and signal transducer and activator of transcription 6 knockout (STAT6KO) mice had a lower number of periodic acid Schiff (PAS)+GCs. We observed that desiccating stress (DS) decreases NK population, GCs, and IL-13, whereas it increases interferon-γ (IFN-γ) mRNA in conjunctiva. Cyclosporine A treatment during DS maintained the number of NK/NKT cells in the conjunctiva, increased IL-13 mRNA in NK+ cells, and decreased IFN-γ and IL-17A mRNA transcripts in NK+ and NK- populations. C57BL/6 mice chronically depleted of NK/NKT cells, as well as NKT cell-deficient RAG1KO and CD1dKO mice, had fewer filled GCs than their wild-type counterparts. NK depletion in CD1dKO mice had no further effect on the number of PAS+ cells. Taken together, these findings indicate that NKT cells are major sources of IL-13 in the conjunctival mucosa that regulates GC homeostasis.

House dust mite extract activates apical Cl(-) channels through protease-activated receptor 2 in human airway epithelia

Adequate fluid secretion from airway mucosa is essential for maintaining mucociliary clearance, and fluid hypersecretion is a prominent feature of inflammatory airway diseases such as allergic rhinitis. House dust mite extract (HDM) has been reported to activate protease-activated receptors (PARs), which play various roles in airway epithelia. However, the role of HDM in regulating ion transporters and fluid secretion has not been investigated. We examined the effect of HDM on ion transport in human primary nasal epithelial cells. The Ca(2+)-sensitive dye Fura2-AM was used to determine intracellular Ca(2+) concentration ([Ca(2+)](i)) by means of spectrofluorometry in human normal nasal epithelial cells (NHNE). Short-circuit current (Isc) was measured using Ussing chambers. Fluid secretion from porcine airway mucosa was observed by optical measurement. HDM extract (10 microg/Ml) effectively cleaved the PAR-2 peptide and induced an increase of [Ca(2+)](i) that was abolished by desensitization with trypsin, but not with thrombin. Apical application of HDM-induced Isc sensitive to both a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor and a Ca(2+)-activated Cl(-) channel (CaCC) inhibitor. HDM extract also stimulated fluid secretion from porcine airway mucosa. HDM extract activated PAR-2 and apical Cl(-) secretion via CaCC and CFTR, and HDM-induced fluid secretion in porcine airway mucosa. Our results suggest a role for PAR-2 in mucociliary clearance and fluid hypersecretion of airway mucosa in response to air-borne allergens such as HDM.

Goblet cells are derived from a FOXJ1-expressing progenitor in a human airway epithelium

The overproduction of mucus is a key pathology associated with respiratory diseases, such as asthma and chronic obstructive pulmonary disease. These conditions are characterized by an increase in the number of mucus-producing goblet cells in the airways. We have studied the cellular origins of goblet cells using primary human bronchial epithelial cells (HBECs), which can be differentiated to form a stratified epithelium containing ciliated, basal and goblet cells. Treatment of differentiated HBEC cultures with the cytokine IL-13, an important mediator in asthma, increased the numbers of goblet cells and decreased the numbers of ciliated cells. To determine whether ciliated cells act as goblet cell progenitors, ciliated cells in HBEC cultures were hereditably labeled with enhanced green fluorescent protein (EGFP) using two lentiviral vectors, one which contained Cre recombinase under the control of a FOXJ1 promoter and a second Cytomegalovirus (CMV)-floxed-EGFP construct. The fate of the EGFP-labeled ciliated cells was tracked in HBEC cultures. Treatment with IL-13 reduced the numbers of EGFP-labeled ciliated cells compared with untreated cultures. In contrast, IL-13 treatment significantly increased the numbers of EGFP-labeled goblet cells. This study demonstrates that goblet cells formed in response to IL-13 treatment are in part or wholly derived from progenitors that express the ciliated cell marker, FOXJ1.

Mucin gene deficiency in mice impairs host resistance to an enteric parasitic infection

BACKGROUND & AIMS

Hyperplasia of mucin-secreting intestinal goblet cells accompanies a number of enteric infections, including infections by nematode parasites. Nevertheless, the precise role of mucins in host defense in nematode infection is not known. We investigated the role of the mucin (Muc2) in worm expulsion and host immunity in a model of nematode infection.

METHODS

Resistant (BALB/c, C57BL/6), susceptible (AKR), and Muc2-deficient mouse strains were infected with the nematode, Trichuris muris, and worm expulsion, energy status of the whipworms, changes in mucus/mucins, and inflammatory and immune responses were investigated after infection.

RESULTS

The increase in Muc2 production, observed exclusively in resistant mice, correlated with worm expulsion. Moreover, expulsion of the worms from the intestine was significantly delayed in the Muc2-deficient mice. Although a marked impairment in the development of periodic acid Schiff (PAS)-stained intestinal goblet cells was observed in Muc2-deficient mice, as infection progressed a significant increase in the number of PAS-positive goblet cells was observed in these mice. Surprisingly, an increase in Muc5ac, a mucin normally expressed in the airways and stomach, was observed after infection of only the resistant animals. Overall, the mucus barrier in the resistant mice was less permeable than that of susceptible mice. Furthermore, the worms isolated from the resistant mice had a lower energy status.

CONCLUSIONS

Mucins are an important component of innate defense in enteric infection; this is the first demonstration of the important functional contribution of mucins to host protection from nematode infection.

Interleukin-13-induced mucous metaplasia increases susceptibility of human airway epithelium to rhinovirus infection

Infection of airway epithelium by rhinovirus is the most common cause of asthma exacerbations. Even in mild asthma, airway epithelium exhibits mucous metaplasia, which increases with increasing severity of the disease. We previously showed that squamous cultures of human airway epithelium manifest rhinoviral infection at levels many times higher than in well-differentiated cultures of a mucociliary phenotype. Here we tested the hypothesis that mucous metaplasia is also associated with increased levels of rhinoviral infection. Mucous metaplasia was induced with IL-13, which doubled the numbers of goblet cells. In both control (mucociliary) and IL-13- treated (mucous metaplastic) cultures, goblet cells were preferentially infected by rhinovirus. IL-13 doubled the numbers of infected cells by increasing the numbers of infected goblet cells. Furthermore, IL-13 increased both the maturity of goblet cells and the probability that a goblet cell would be infected. The infection of cells other than goblet cells was unaltered by IL-13. Treatment with IL-13 did not alter the levels of rhinovirus receptor ICAM-1, nor did the proliferative effects of IL-13 enhance infection, because rhinovirus did not colocalize with dividing cells. However, the induction of mucous metaplasia caused changes in the apical membrane structure, notably a marked decrease in overall ciliation, and an increase in the overall flatness of the apical surface. We conclude that mucous metaplasia in asthma increases the susceptibility of airway epithelium to infection by rhinovirus because of changes in the overall architecture of the apical surface.

Regulation of mucin expression in respiratory diseases

Respiratory diseases such as asthma and COPD (chronic obstructive pulmonary disease) are characterized by increased numbers of goblet cells and excessive mucus production, which contribute to the underlying disease pathology. Mucins form a major component of the mucus contributing to its viscoelastic properties, and in the airways the mucins MUC5AC and MUC5B are found at increased levels in both asthmatic and COPD subjects. A diverse range of stimuli have been shown to regulate MUC5AC expression and cause increases in the number of mucus-producing goblet cells. Perhaps the best characterized of these mediators is the cytokine IL (interleukin)-13, which causes increases in MUC5AC-expressing goblet cells in the airways. Several transcription factors have been linked with goblet cell formation and mucus production and include STAT6 (signal transducer and activator of transcription 6), FOXA2 (forkhead box A2) and the SPDEF [SAM (sterile alpha motif) domain-containing prostate-derived Ets factor]. In mouse airways, goblet cells are normally rare or absent, but increase rapidly in number in response to certain stimuli. The origins of these goblet cells are not well understood, although Clara cells and ciliated cells have been implicated as goblet cell progenitors. An understanding of the origin and processes regulating goblet cell formation in human airway epithelial cells has important implications for the identification of therapeutic targets to treat respiratory diseases.