CLCA1 and TMEM16A: the link towards a potential cure for airway diseases

Serotonin-2 Receptor Agonists Produce Anti-inflammatory Effects through Functionally Selective Mechanisms That Involve the Suppression of Disease-Induced Arginase 1 Expression

Functional selectivity in the context of serotonin 2A (5-HT2A) receptor agonists is often described as differences psychedelic compounds have in the activation of Gq vs β-arrestin signaling in the brain and how that may relate to inducing psychoactive and hallucinatory properties with respect to each other. However, the presence of 5-HT2A receptors throughout the body in several cell types, including endothelial, endocrine, and immune-related tissues, suggests that functional selectivity may exist in the periphery as well. Here, we examine functional selectivity between two 5-HT2A receptor agonists of the phenylalkylamine class: (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] and (R)-2,5-dimethoxy-4-trifluoromethylamphetamine [(R)-DOTFM]. Despite comparable in vitro activity at the 5-HT2A receptor as well as similar behavioral potency, (R)-DOTFM does not exhibit an ability to prevent inflammation or elevated airway hyperresponsiveness (AHR) in an acute murine ovalbumin-induced asthma model as does (R)-DOI. Furthermore, there are distinct differences between protein expression and inflammatory-related gene expression in pulmonary tissues between the two compounds. Using (R)-DOI and (R)-DOTFM as tools, we further elucidated the anti-inflammatory mechanisms underlying the powerful anti-inflammatory effects of certain psychedelics and identified key mechanistic components of the anti-inflammatory effects of psychedelics, including suppression of arginase 1 expression.

Structure and Function of Calcium-Activated Chloride Channels and Phospholipid Scramblases in the TMEM16 Family

The transmembrane protein 16 (TMEM16) family consists of Ca2+-activated chloride channels and phospholipid scramblases. Ten mammalian TMEM16 proteins, TMEM16A-K (with no TMEM16I), and several non-mammalian TMEM16 proteins, such as afTMEM16 and nhTMEM16, have been discovered. All known TMEM16 proteins are homodimeric proteins containing two subunits. Each subunit consists of ten transmembrane helices with Ca2+-binding sites and a single ion-permeation/phospholipid transport pathway. The ion-permeation pathway and the phospholipid transport pathway of TMEM16 proteins have a wide intracellular vestibule, a narrow neck, and a smaller extracellular vestibule. Interestingly, the lining wall of the ion-permeation/phospholipid transport pathway may be formed, at least partially, by membrane phospholipids, though the degree of pore-wall forming by phospholipids likely varies among TMEM16 proteins. Thus, the biophysical properties and activation mechanisms of TMEM16 proteins could differ from each other accordingly. Here we review the current understanding of the structure and function of TMEM16 molecules.

Transcriptional profiling of mucus production and modification in rhesus macaque endocervical cells under hormonal regulation

Objective

Endocervical mucus production is a key regulator of fertility throughout the menstrual cycle. With cycle-dependent variability in mucus quality and quantity, cervical mucus can either facilitate or block sperm ascension into the upper female reproductive tract. This study seeks to identify genes involved in the hormonal regulation of mucus production, modification, and regulation through profiling the transcriptome of endocervical cells from the non-human primate, the Rhesus Macaque (Macaca mulatta).

Design

Experimental.

Setting

Translational science laboratory.

Intervention

We treated differentiated primary endocervical cultures with estradiol (E2) and progesterone (P4) to mimic peri-ovulatory and luteal-phase hormonal changes. Using RNA-sequencing, we identified differential expression of gene pathways and mucus producing and modifying genes in cells treated with E2 compared to hormone-free conditions and E2 compared to E2-primed cells treated with P4.

Main Outcome Measures

We pursued differential gene expression analysis on RNA-sequenced cells. Sequence validation was done using qPCR.

Results

Our study identified 158 genes that show significant differential expression in E2-only conditions compared to hormone-free control, and 250 genes that show significant differential expression in P4-treated conditions compared to E2-only conditions. From this list, we found hormone-induced changes in transcriptional profiles for genes across several classes of mucus production, including ion channels and enzymes involved in post-translational mucin modification that have not previously been described as hormonally regulated.

Conclusion

Our study is the first to use an in vitro culture system to create an epithelial-cell specific transcriptome of the endocervix. As a result, our study identifies new genes and pathways that are altered by sex-steroids in cervical mucus production.

Hormonal regulation of non-cystic fibrosis transmembrane conductance regulator ion channels in the endocervix

OBJECTIVE

To characterize ion channel expression and localization in the endocervix under different hormonal conditions using a nonhuman primate primary endocervical epithelial cell model.

DESIGN

Experimental.

SETTING

University-based, translational science laboratory.

INTERVENTIONS

We cultured and treated conditionally reprogrammed primary rhesus macaque endocervix cells with estradiol and progesterone and measured gene expression changes for several known ion channel and ion channel regulators of mucus secreting epithelia. Using both rhesus macaque endocervical samples and human samples, we localized channels in the endocervix using immunohistochemistry.

MAIN OUTCOME MEASURES

The relative abundance of transcripts was evaluated using real-time polymerase chain reaction. Immunostaining results were evaluated qualitatively.

RESULTS

Compared with controls, we found that estradiol increased gene expression for ANO6, NKCC1, CLCA1, and PDE4D. Progesterone down-regulated gene expression for ANO6, SCNN1A, SCNN1B, NKCC1, and PDE4D (P≤.05). Immunohistochemistry confirmed endocervical cell membrane localization of ANO1, ANO6, KCNN4, LRR8CA, and NKCC1.

CONCLUSIONS

We found several ion channels and ion channel regulators that are hormonally sensitive in the endocervix. These channels, therefore, may play a role in the cyclic fertility changes in the endocervix and could be further investigated as targets for future fertility and contraceptive studies.

Transcriptomic Differentiation of Phenotypes in Chronic Rhinosinusitis and Its Implications for Understanding the Underlying Mechanisms

Chronic rhinosinusitis (CRS) is a multifaceted disease with variable clinical courses and outcomes. We aimed to determine CRS-associated nasal-tissue transcriptome in clinically well-characterized and phenotyped individuals, to gain a novel insight into the biological pathways of the disease. RNA-sequencing of tissue samples of patients with CRS with polyps (CRSwNP), without polyps (CRSsNP), and controls were performed. Characterization of differently expressed genes (DEGs) and functional and pathway analysis was undertaken. We identified 782 common CRS-associated nasal-tissue DEGs, while 375 and 328 DEGs were CRSwNP- and CRSsNP-specific, respectively. Common key DEGs were found to be involved in dendritic cell maturation, the neuroinflammation pathway, and the inhibition of the matrix metalloproteinases. Distinct CRSwNP-specific DEGs were involved in NF-kβ canonical pathways, Toll-like receptor signaling, HIF1α regulation, and the Th2 pathway. CRSsNP involved the NFAT pathway and changes in the calcium pathway. Our findings offer new insights into the common and distinct molecular mechanisms underlying CRSwNP and CRSsNP, providing further understanding of the complex pathophysiology of the CRS, with future research directions for novel treatment strategies.

Patent highlights February-March 2021

A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.

Analysis of Lung Gene Expression Reveals a Role for Cl- Channels in Diisocyanate-induced Airway Eosinophilia in a Mouse Model of Asthma Pathology

Diisocyanates are well-recognized causes of asthma. However, sensitized workers frequently lack diisocyanate-specific IgE, which complicates diagnosis and suggests the disease involves IgE-independent mechanisms. We used a mouse model of methylene diphenyl diisocyanate (MDI) asthma to identify biological pathways that may contribute to asthma pathogenesis. MDI sensitization and respiratory tract exposure were performed in Balb/c, transgenic B-cell (e.g., IgE)-deficient mice and a genetic background (C57BL/6)-matched strain. Eosinophils in airway fluid were quantitated by flow cytometry. Lung tissue gene expression was assessed using whole-genome mRNA microarrays. Informatic software was used to identify biological pathways affected by respiratory tract exposure and potential targets for disease intervention. Airway eosinophilia and changes (>1.5-fold; P value < 0.05) in expression of 192 genes occurred in all three mouse strains tested, with enrichment in chemokines and a pattern associated with alternatively activated monocytes/macrophages. CLCA1 (calcium-activated chloride channel regulator 1) was the most upregulated gene transcript (>100-fold) in all exposed mouse lungs versus controls, followed closely by SLC26A4, another transcript involved in Cl- conductance. Crofelemer, a U.S. Food and Drug Administration-approved Cl- channel inhibitor, reduced MDI exposure induction of airway eosinophilia, mucus, CLCA1, and other asthma-associated gene transcripts. Expression changes in a core set of genes occurs independent of IgE in a mouse model of chemical-induced airway eosinophilia. In addition to chemokines and alternatively activated monocytes/macrophages, the data suggest a crucial role for Cl- channels in diisocyanate asthma pathology and as a possible target for intervention.

Tiotropium and Fluticasone Inhibit Rhinovirus-Induced Mucin Production via Multiple Mechanisms in Differentiated Airway Epithelial Cells

Human rhinoviruses (HRVs) are associated with acute exacerbations in patients with chronic obstructive pulmonary disease (COPD) and asthma, which are accompanied by mucus hypersecretion. Whereas, various studies have shown that HRVs increase epithelial mucin production and thus may directly contribute to mucus hypersecretion. The effects of drugs used in the treatment of COPD and asthma on HRV-induced mucin production in epithelial cell cultures have not been studied. In the present study, we assessed effects of HRVs on mucin production and secretion in well-differentiated primary human bronchial epithelial cells (PBEC) and studied the effect of the inhaled corticosteroid fluticasone propionate and the long-acting muscarinic antagonist tiotropium bromide on this process. Differentiated PBEC that were cultured at the air-liquid interface (ALI-PBEC) were infected with HRV-A16 and HRV-1B. Quantitative PCR, immunofluorescence staining, ELISA, periodic acid-Schiff (PAS) staining and immunostaining assays were used to assess the effects of HRV infection. Here we demonstrate that both HRV-A16 and HRV-1B increased mucin (MUC5AC and MUC5B) gene expression and protein release. When exploring this in more detail in HRV-A16-infected epithelial cells, mucin expression was found to be accompanied by increases in expression of SAM-pointed domain-containing Ets-like factor (SPDEF) and SPDEF-regulated genes known to be involved in the regulation of mucin production. We also found that pre-treatment with the purinergic P2R antagonist suramin inhibits HRV-enhanced MUC5AC expression and protein release, implicating involvement of purinergic signaling by extracellular ATP. We furthermore found that both fluticasone and tiotropium decreased HRV-induced mucin production without affecting viral replication, and obtained evidence to suggest that the inhibitory effect of fluticasone involved modulation of SPDEF-regulated genes and extracellular ATP release. These data show that both tiotropium and fluticasone inhibit HRV-induced epithelial mucin production independent of viral clearance, and thus provide insight into the mechanisms underlying beneficial effects of tiotropium and fluticasone in the treatment of COPD, asthma and accompanying exacerbations in these patients. Furthermore, our findings provide additional insight into the mechanisms by which HRV increases epithelial mucin production.

Identification of critical genes associated with the development of asthma by co-expression modules construction

INTRODUCTION

Asthma is a worldwide problem that is caused by complex underlying immune dysregulation. The identification of potential prognostic markers of asthma may provide information for treatment. The purpose of this study was to explore the key mechanisms involved in the development of asthma on the basis of microarray analysis.

METHODS

The expression profile data of GSE43696, which contains 20 endobronchial epithelial brushing samples from healthy patients and 88 from asthma patients, were obtained from Gene Expression Omnibus. For the present study, we built co-expression modules by weighted gene co-expression network analysis (WGCNA). This new analysis strategy was applied to the data set to investigate the relationships underlying the modules and the pathogenesis of asthma. Functional enrichment analysis was performed on these co-expression genes from the modules, and a gene network was then constructed. In addition, mouse models of HDM-induced and OVA-induced asthma were established, and the expression of hub genes was measured.

RESULTS

First, using WGCNA, 20 co-expression modules were constructed with 19,596 genes obtained from 108 human endobronchial epithelial brushing samples. The number of genes within the modules ranged from 41 to 845. According to the colours assigned by the system, the module positively correlated with asthma status was named 'red module', and the module positively correlated with asthma severity was named 'purple module'. The results of a functional enrichment analysis showed that the red module was mainly enriched in intracellular calcium-activated chloride channel activity, intracellular chloride channel activity and endopeptidase inhibitor activity. The purple module was mainly enriched in microtubule motor activity and microtubule-binding and motor activity. Moreover, the mRNA expression levels of the 15 hub genes were confirmed to be significantly upregulated in the HDM mouse model, and 12 hub genes were upregulated in the OVA model.

CONCLUSIONS

The hub genes ANO7, PYCR1 and UBE2C might play potential roles in the pathogenesis of asthma. Our findings provided a framework of co-expression gene modules of asthma and led to the identification of some new markers that might be potential targets for the development of new drugs and diagnostic markers.

Assessing the unified airway hypothesis in children via transcriptional profiling of the airway epithelium

BACKGROUND

Emerging evidence suggests that disease vulnerability is expressed throughout the airways, the so-called unified airway hypothesis, but the evidence to support this is predominantly indirect.

OBJECTIVES

We sought to establish the transcriptomic profiles of the upper and lower airways and determine their level of similarity irrespective of airway symptoms (wheeze) and allergy.

METHODS

We performed RNA sequencing on upper and lower airway epithelial cells from 63 children with or without wheeze and accompanying atopy, using differential gene expression and gene coexpression analyses to determine transcriptional similarity.

RESULTS

We observed approximately 91% homology in the expressed genes between the 2 sites. When coexpressed genes were grouped into modules relating to biological functions, all were found to be conserved between the 2 regions, resulting in a consensus network containing 16 modules associated with ribosomal function, metabolism, gene expression, mitochondrial activity, and antiviral responses through IFN activity. Although symptom-associated gene expression changes were more prominent in the lower airway, they were reflected in nasal epithelium and included IL-1 receptor like 1, prostaglandin-endoperoxide synthase 1, CCL26, and periostin. Through network analysis we identified a cluster of coexpressed genes associated with atopic wheeze in the lower airway, which could equally distinguish atopic and nonatopic phenotypes in upper airway samples.

CONCLUSIONS

We show that the upper and lower airways are significantly conserved in their transcriptional composition, and that variations associated with disease are present in both nasal and tracheal epithelium. Findings from this study supporting a unified airway imply that clinical insight regarding the lower airway in health and disease can be gained from studying the nasal epithelium.

Diesel exhaust particle and dust mite induced airway inflammation is modified by cerium dioxide nanoparticles

Cerium dioxide nanoparticles (CeO₂NPs) have been used as diesel fuel-borne catalysts for improved efficiency and pollutant emissions. Concerns that such material may influence diesel exhaust particle (DEP) effects within the lung upon inhalation, prompted us to examine particle responses in mice in the presence and absence of the common allergen house dust mite (HDM). Repeated intranasal instillation of combined HDM and DEP increased airway mucin, eosinophils, lymphocytes, IL-5, IL-13, IL-17A and plasma IgE, which were further increased with CeO₂NPs co-exposure. A single co-exposure of CeO₂NPs and DEP after repeated HDM exposure increased macrophage and IL-17A levels above DEP induced levels. CeO₂NPs exposure in the absence of HDM also resulted in increased levels of plasma IgE and airway mucin staining, changes not observed with repeated DEP exposure alone. These observations indicate that CeO₂NPs can modify exhaust particulate and allergen induced inflammatory events in the lung with the potential to influence conditions such as allergic airway disease.

TMEM16A chloride channel does not drive mucus production

Despite being essential for airway hydration, TMEM16A is not required for mucus (MUC5AC) production. Cell proliferation is the main driver for TMEM16A up-regulation during inflammation.

Airway mucus obstruction is the main cause of morbidity in cystic fibrosis, a disease caused by mutations in the CFTR Cl⁻ channel. Activation of non-CFTR Cl⁻ channels such as TMEM16A can likely compensate for defective CFTR. However, TMEM16A was recently described as a key driver in mucus production/secretion. Here, we have examined whether indeed there is a causal relationship between TMEM16A and MUC5AC production, the main component of respiratory mucus. Our data show that TMEM16A and MUC5AC are inversely correlated during differentiation of human airway cells. Furthermore, we show for the first time that the IL-4–induced TMEM16A up-regulation is proliferation-dependent, which is supported by the correlation found between TMEM16A and Ki-67 proliferation marker during wound healing. Consistently, the notch signaling activator DLL4 increases MUC5AC levels without inducing changes neither in TMEM16A nor in Ki-67 expression. Moreover, TMEM16A inhibition decreased airway surface liquid height. Altogether, our findings demonstrate that up-regulation of TMEM16A and MUC5AC is only circumstantial under cell proliferation, but with no causal relationship between them. Thus, although essential for airway hydration, TMEM16A is not required for MUC5AC production.

Ion channels as therapeutic antibody targets

It is now well established that antibodies have numerous potential benefits when developed as therapeutics. Here, we evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. Additionally, we discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.

Fra2 Overexpression in Mice Leads to Non-allergic Asthma Development in an IL-13 Dependent Manner

Background: Asthma is a complex chronic inflammatory disease characterised by airway inflammation, remodelling and hyperresponsiveness (AHR). Members of the AP-1 transcription factor family play important roles in the activation of the immune system and the control of cellular responses; however, their role in the development of asthma has not been well studied. We aimed to investigate the role of the lesser known AP-1 family member, Fra2 in experimental asthma.

Methods: Phenotypic characterisation and gene expression profiling was performed on Fra2 (TG) overexpressing and wild-type mice. The efficacy of therapeutic interventions in regulating the Fra2 phenotype was determined.

Results: Transcriptional profiling of TG mice revealed a high abundance of regulated genes associated with airway remodelling, inflammation and mucus production. A concomitant increase in peribronchial collagen deposition, smooth muscle thickening and mucus production was observed. TG mice possessed increased inflammatory infiltration in the lung, predominantly consisting of eosinophils and T-cells and elevated expression of Th2 cytokines and eotaxin. Furthermore, TG mice possessed severe AHR in response to increasing doses of methacholine. Glucocorticoid treatment led to a partial improvement of the asthma phenotype, whereas blockade of IL-13 via neutralising antibodies ameliorated AHR and mucus production, but had no effect on collagen deposition.

Conclusion: We here describe a novel model for non-allergic asthma that does not require the application of exogenous allergens, which mimics several key features of the disease, such as airway inflammation, remodelling and hyperresponsiveness. Fra2 may represent a key molecule coordinating multiple aspects of asthma pathogenesis.

Cerium dioxide nanoparticles exacerbate house dust mite induced type II airway inflammation

Background

Nanomaterial inhalation represents a potential hazard for respiratory conditions such as asthma. Cerium dioxide nanoparticles (CeO₂NPs) have the ability to modify disease outcome but have not been investigated for their effect on models of asthma and inflammatory lung disease. The aim of this study was to examine the impact of CeO₂NPs in a house dust mite (HDM) induced murine model of asthma.

Results

Repeated intranasal instillation of CeO₂NPs in the presence of HDM caused the induction of a type II inflammatory response, characterised by increased bronchoalveolar lavage eosinophils, mast cells, total plasma IgE and goblet cell metaplasia. This was accompanied by increases in IL-4, CCL11 and MCPT1 gene expression together with increases in the mucin and inflammatory regulators CLCA1 and SLC26A4. CLCA1 and SLC26A4 were also induced by CeO₂NPs + HDM co-exposure in air liquid interface cultures of human primary bronchial epithelial cells. HDM induced airway hyperresponsiveness and airway remodelling in mice were not altered with CeO₂NPs co-exposure. Repeated HMD instillations followed by a single exposure to CeO₂NPs failed to produce changes in type II inflammatory endpoints but did result in alterations in the neutrophil marker CD177. Treatment of mice with CeO₂NPs in the absence of HDM did not have any significant effects. RNA-SEQ was used to explore early effects 24 h after single treatment exposures. Changes in SAA3 expression paralleled increased neutrophil BAL levels, while no changes in eosinophil or lymphocyte levels were observed. HDM resulted in a strong induction of type I interferon and IRF3 dependent gene expression, which was inhibited with CeO₂NPs co-exposure. Changes in the expression of genes including CCL20, CXCL10, NLRC5, IRF7 and CLEC10A suggest regulation of dendritic cells, macrophage functionality and IRF3 modulation as key early events in how CeO₂NPs may guide pulmonary responses to HDM towards type II inflammation.

Conclusions

CeO₂NPs were observed to modulate the murine pulmonary response to house dust mite allergen exposure towards a type II inflammatory environment. As this type of response is present within asthmatic endotypes this finding may have implications for how occupational or incidental exposure to CeO₂NPs should be considered for those susceptible to disease.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0261-5) contains supplementary material, which is available to authorized users.

Identification of Resveratrol, an Herbal Compound, as an Activator of the Calcium-Activated Chloride Channel, TMEM16A

Calcium-activated chloride channels (CaCCs) play vital roles in a variety of physiological processes. Dysfunction of the CaCCs is implicated in many diseases. Drug discovery targeting at CaCCs has recently become possible with the determination that TMEM16A is the molecular identity of CaCCs. In this study, we demonstrated that resveratrol (RES), a Chinese traditional medicine compound, is a novel activator of TMEM16A. The yellow fluorescence protein quenching assay and measurement of intracellular calcium fluorescence intensity show that RES activates TMEM16A channels in an intracellular Ca²⁺-independent way. The data of inside-out patch clamp revealed that RES dose-dependently activates TMEM16A (EC₅₀ = 47.92 ± 9.35 μM). Furthermore, RES enhanced the contractions of the ileum of guinea pigs by activating the TMEM16A channel, which indicated that RES might be a promising drug for the treatment of gastrointestinal hypomotility. As RES was able to induce TMEM16A channel activation, TMEM16A can be added to the list of RES drug targets.

Modulation of TMEM16A channel activity by the von Willebrand factor type A (VWA) domain of the calcium-activated chloride channel regulator 1 (CLCA1)

Calcium-activated chloride channels (CaCCs) are key players in transepithelial ion transport and fluid secretion, smooth muscle constriction, neuronal excitability, and cell proliferation. The CaCC regulator 1 (CLCA1) modulates the activity of the CaCC TMEM16A/Anoctamin 1 (ANO1) by directly engaging the channel at the cell surface, but the exact mechanism is unknown. Here we demonstrate that the von Willebrand factor type A (VWA) domain within the cleaved CLCA1 N-terminal fragment is necessary and sufficient for this interaction. TMEM16A protein levels on the cell surface were increased in HEK293T cells transfected with CLCA1 constructs containing the VWA domain, and TMEM16A-like currents were activated. Similar currents were evoked in cells exposed to secreted VWA domain alone, and these currents were significantly knocked down by TMEM16A siRNA. VWA-dependent TMEM16A modulation was not modified by the S357N mutation, a VWA domain polymorphism associated with more severe meconium ileus in cystic fibrosis patients. VWA-activated currents were significantly reduced in the absence of extracellular Mg²⁺, and mutation of residues within the conserved metal ion-dependent adhesion site motif impaired the ability of VWA to potentiate TMEM16A activity, suggesting that CLCA1-TMEM16A interactions are Mg²⁺- and metal ion-dependent adhesion site-dependent. Increase in TMEM16A activity occurred within minutes of exposure to CLCA1 or after a short treatment with nocodazole, consistent with the hypothesis that CLCA1 stabilizes TMEM16A at the cell surface by preventing its internalization. Our study hints at the therapeutic potential of the selective activation of TMEM16A by the CLCA1 VWA domain in loss-of-function chloride channelopathies such as cystic fibrosis.

Increased expression of hCLCA1 in chronic rhinosinusitis and its contribution to produce MUC5AC

OBJECTIVES/HYPOTHESIS

Mucus hypersecretion is a hallmarks of chronic rhinosinusitis. The expression of MUC5AC, a major respiratory mucin gene, is increased in chronic rhinosinusitis. The mechanisms inducing mucus hypersecretion have not been fully evaluated in chronic rhinosinusitis. Human Ca²⁺ -activated Cl- channel 1 (hCLCA1) is implicated in the regulation of mucus production, airway fluid, and electrolyte transport. The present study objectives was to investigate the expression of hCLCA1 in chronic rhinosinusitis and evaluate whether its level is altered by stimulation with type 1 T helper (Th1) and Th2 cytokines, and to determine the possible role of hCLCA1 on the regulation of mucin 5AC (MUC5AC) production.

STUDY DESIGN

Controlled prospective study.

METHODS

The expression of hCLCA1 and MUC5AC in normal and inflammatory ethmoid mucosa was determined by real-time polymerase chain reaction, immunohistochemistry, and Western blot. In cultured cells, the expression of hCLCA1 and MUC5AC was measured after stimulation with Th1 and Th2 cytokines. In a supernatant, the MUC5AC level was analyzed using enzyme-linked immunosorbent assay after treatment with niflumic acid.

RESULTS

The levels of hCLCA1 and MUC5AC were increased in chronic rhinosinusitis, irrespective of nasal polyp presence, where they were distributed in superficial epithelial cells and submucosal glands. In cultured cells treated with interleukin (IL)-9, IL-4, IL-13, tumor necrosis factor-α, transforming growth factor-β, interferon-γ, and IL-1β, the expression of hCLCA1 and MUC5AC was increased. In cells treated with niflumic acid, the production of MUC5AC was inhibited.

CONCLUSIONS

The current findings indicate that the expression of hCLCA1 is increased in chronic rhinosinusitis and may be regulated by Th1 and Th2 cytokines, possibly contributing to the production of MUC5AC.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:E347-E355, 2016.