Environment and lung health in a rapidly changing world

This issue of the European Respiratory Review features the first articles in a series of reviews entitled “Environment and lung health in a rapidly changing world”. This series aims to highlight and dissect the complex intersections of environmental factors and their impact on human lung health. Additionally, the series addresses some more specific issues that we continue to face in the 21st century, including health inequity, the increasingly fast-paced integration of artificial intelligence (AI) into every day medical practice and climate change.

In the 21st century, respiratory health delivery continues to face significant challenges in the context of climate change, plastic pollution, artificial intelligence and continued health inequity. Will we make changes in time? https://bit.ly/3TS9jnO

Global respiratory health priorities at the beginning of the 21st century

Respiratory health has become a prevailing priority amid the diverse global health challenges that the 21st century brings, due to its substantial impact on individuals and communities on a global scale. Due to rapid advances in medicine, emerging knowledge gaps appear along with new challenges and ethical considerations. While breakthroughs in medical science can bring about encouraging possibilities for better treatments and interventions, they also lead to unanswered questions and areas where further research is warranted. A PubMed search on the topic "global respiratory health priorities" between the years 2000 and 2023 was conducted, which returned 236 articles. Of these, 55 were relevant and selected for inclusion in this article. The selection process took into account literature reviews, opinions from expert groups and careful analysis of existing gaps and challenges within the field; our selection encompasses specific infectious and noninfectious respiratory conditions in both adults and children. The global respiratory health priorities identified were selected on the basis that they have been recognised as critical areas of investigation and potential advancement and they span across clinical, translational, epidemiological and population health domains. Implementing these priorities will require a commitment to fostering collaboration and knowledge-sharing among experts in different fields with the ultimate aim to improve respiratory health outcomes for individuals and communities alike.

TGF-β1 Inhibition of ACE2 Mediated by miRNA Uncovers Novel Mechanism of SARS-CoV-2 Pathogenesis

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for COVID-19, utilizes receptor binding domain (RBD) of spike glycoprotein to interact with angiotensin (Ang)-converting enzyme 2 (ACE2). Altering ACE2 levels may affect entry of SARS-CoV-2 and recovery from COVID-19. Decreased cell surface density of ACE2 leads to increased local levels of Ang II and may contribute to mortality resulting from acute lung injury and fibrosis during COVID-19. Studies published early during the COVID-19 pandemic reported that people with cystic fibrosis (PwCF) had milder symptoms, compared to people without CF. This finding was attributed to elevated ACE2 levels and/or treatment with the high efficiency CFTR modulators. Subsequent studies did not confirm these findings reporting variable effects of CFTR gene mutations on ACE2 levels. Transforming growth factor (TGF)-β signaling is essential during SARS-CoV-2 infection and dominates the chronic immune response in severe COVID-19, leading to pulmonary fibrosis. TGF-β1 is a gene modifier associated with more severe lung disease in PwCF but its effects on the COVID-19 course in PwCF is unknown. To understand whether TGF-β1 affects ACE2 levels in the airway, we examined miRNAs and their gene targets affecting SARS-CoV-2 pathogenesis in response to TGF-β1. Small RNAseq and micro(mi)RNA profiling identified pathways uniquely affected by TGF-β1, including those associated with SARS-CoV-2 invasion, replication, and the host immune responses. TGF-β1 inhibited ACE2 expression by miR-136-3p and miR-369-5p mediated mechanism in CF and non-CF bronchial epithelial cells. ACE2 levels were higher in two bronchial epithelial cell models expressing the most common CF-causing mutation in CFTR gene F508del, compared to controls without the mutation. After TGF-β1 treatment, ACE2 protein levels were still higher in CF, compared to non-CF cells. TGF-β1 prevented the modulator-mediated rescue of F508del-CFTR function while the modulators did not prevent the TGF-β1 inhibition of ACE2 levels. Finally, TGF-β1 reduced the interaction between ACE2 and the recombinant spike RBD by lowering ACE2 levels and its binding to RBD. Our data demonstrate novel mechanism whereby TGF-β1 inhibition of ACE2 in CF and non-CF bronchial epithelial cells may modulate SARS-CoV-2 pathogenicity and COVID-19 severity. By reducing ACE2 levels, TGF-β1 may decrease entry of SARS-CoV-2 into the host cells while hindering the recovery from COVID-19 due to loss of the anti-inflammatory and regenerative effects of ACE2. The above outcomes may be modulated by other, miRNA-mediated effects exerted by TGF-β1 on the host immune responses, leading to a complex and yet incompletely understood circuitry.

Basic, translational and clinical aspects of bronchiectasis in adults

Bronchiectasis is a common progressive respiratory disease with recognisable radiological abnormalities and a clinical syndrome of cough, sputum production and recurrent respiratory infections. Inflammatory cell infiltration into the lung, in particular neutrophils, is central to the pathophysiology of bronchiectasis. Herein we explore the roles and relationships between infection, inflammation and mucociliary clearance dysfunction in the establishment and progression of bronchiectasis. Microbial and host-mediated damage are important processes underpinning bronchiectasis and the relative contribution of proteases, cytokines and inflammatory mediators to the propagation of inflammation is presented. We also discuss the emerging concept of inflammatory endotypes, defined by the presence of neutrophilic and eosinophilic inflammation, and explore the role of inflammation as a treatable trait. Current treatment for bronchiectasis focuses on treatment of underlying causes, enhancing mucociliary clearance, controlling infection and preventing and treating complications. Data on airway clearance approaches via exercise and mucoactive drugs, pharmacotherapy with macrolides to decrease exacerbations and the usefulness of inhaled antibiotics and bronchodilators are discussed, finishing with a look to the future where new therapies targeting host-mediated immune dysfunction hold promise.

ERS international Congress 2022: highlights from the Basic and Translational Science Assembly

In this review the Basic and Translational Science Assembly of the European Respiratory Society (ERS) provides an overview of the 2022 international conference highlights. We discuss the consequences of respiratory events from birth until old age regarding climate change-related alterations in air quality due to pollution caused by increased ozone, pollen, wildfires and fuel combustion as well as the increasing presence of microplastic and microfibres. Early life events such as the effect of hyperoxia in the context of bronchopulmonary dysplasia and crucial effects of the intrauterine environment in the context of preeclampsia were discussed. The Human Lung Cell Atlas (HLCA) was put forward as a new point of reference for healthy human lungs. The combination of single-cell RNA-sequencing and spatial data in the HLCA has enabled the discovery of new cell types/states, new niches and served as a platform that facilitates further investigation of mechanistic perturbations. The role of cell death modalities in regulating the onset and progression of chronic lung diseases and its potential as a therapeutic target was also discussed. Translational studies identified novel therapeutic targets and immunoregulatory mechanisms in asthma. Lastly, it was highlighted that the choice of regenerative therapeutic depends on disease severity, ranging from transplantation to cell therapies and regenerative pharmacology.

Long Non-Coding RNA Expression in Alpha-1 Antitrypsin Deficient Monocytes Pre- and Post-AAT Augmentation Therapy

Long non-coding RNAs (lncRNAs) regulate gene expression. Their expression in alpha-1 antitrypsin (AAT) deficiency has not been investigated. Treatment of AAT deficiency involves infusion of plasma-purified AAT and this augmentation therapy has previously been shown to alter microRNA expression in monocytes of AAT-deficient (ZZ) individuals. Here, we assess the effect of AAT augmentation therapy on the lncRNA expression profile in ZZ monocytes. Peripheral blood monocytes were isolated from ZZ individuals pre (Day 0)- and post (Day 2)-AAT augmentation therapy. Arraystar lncRNA microarray profiling was performed; a total of 17,761 lncRNAs were detectable across all samples. The array identified 7509 lncRNAs with differential expression post-augmentation therapy, 3084 were increased and 4425 were decreased (fold change ≥ 2). Expression of many of these lncRNAs were similarly altered in ZZ monocytes treated ex vivo with 27.5 μM AAT for 4 h. These properties may contribute to the manifold effects of AAT augmentation therapy.

Sexual Dimorphism in Interstitial Lung Disease

Interstitial lung diseases (ILD) are a group of heterogeneous progressive pulmonary disorders, characterised by tissue remodelling and/or fibrotic scarring of the lung parenchyma. ILD patients experience lung function decline with progressive symptoms, poor response to treatment, reduced quality of life and high mortality. ILD can be idiopathic or associated with systemic or connective tissue diseases (CTD) but idiopathic pulmonary fibrosis (IPF) is the most common form. While IPF has a male predominance, women are affected more greatly by CTD and therefore associated ILDs. The mechanisms behind biological sex differences in these progressive lung diseases remain unclear. However, differences in environmental exposures, variable expression of X-chromosome related inflammatory genes and sex hormones play a role. Here, we will outline sex-related differences in the incidence, progression and mechanisms of action of these diseases and discuss existing and novel cellular and pre-clinical studies. Furthermore, we will highlight how sex-differences are not adequately considered in pre-clinical disease models, how gender bias exists in clinical diagnosis and how women are underrepresented in clinical trials. Future action on these observations will hopefully shed light on the role of biological sex in disease development, identify potential targets for intervention and increase female participant numbers in clinical trials.

Epithelial damage in the cystic fibrosis lung: the role of host and microbial factors

INTRODUCTION

The airway epithelium is a key system within the lung. It acts as a physical barrier to inhaled factors, and can actively remove unwanted microbes and particles from the lung via the mucociliary escalator. On a physiological level, it senses the presence of pathogens and initiates innate immune responses to combat their effects. Hydration of the airways is also controlled by the epithelium. Within the cystic fibrosis (CF) lung, these properties are suboptimal and contribute to the pulmonary manifestations of CF.

AREAS COVERED

In this review, we discuss how various host and microbial factors can contribute to airway epithelium dysfunction in the CF lung focusing on mechanisms relating to the mucociliary escalator and protease expression and function. We also explore how alterations in microRNA expression can impact the behavior of the airway epithelium.

EXPERT OPINION

Notwithstanding the unprecedented benefits that CFTR modulator drugs now provide to the health of CF sufferers, it will be important to delve more deeply into additional mechanisms underpinning CF lung disease such as those illustrated here in an attempt to counteract these aberrant processes and further enhance quality of life for people with CF.

miR-224-5p and miR-545-5p Levels Relate to Exacerbations and Lung Function in a Pilot Study of X-Linked MicroRNA Expression in Cystic Fibrosis Monocytes

Altered microRNA expression patterns in bronchial brushings from people with versus without cystic fibrosis (CF) relate to functional changes and disease pathophysiology. The expression of microRNAs encoded on the X chromosome is also altered in peripheral blood monocytes of p. Phe508del homozygous versus non-CF individuals. Here we investigate whether levels of the top seven X-linked microRNAs (miR-224-5p, miR-452-5p, miR-450b-5p, miR-542-3p, miR-450a-5p, miR-424-5p, and miR-545-5p) that are significantly increased over 1.5 fold in CF versus non-CF monocytes correlate with lung function. CD14⁺ monocytes were isolated from males and females with (n = 12) and without cystic fibrosis (n = 12) and examined for the expression of X-linked microRNAs by qRT-PCR array. MicroRNA target mRNA levels were quantified using qRT-PCR. Clinical correlations with lung function data were analysed in the CF cohort. Increasing levels of miR-545-5p correlated moderately with FEV1% predicted (r = -0.4553, p > 0.05) and strongly with exacerbation rate (r = 0.5858, p = 0.0483). miR-224-5p levels were significantly higher in the severe (FEV1 <40%) versus mild (FEV1 ≥80%, p = 0.0377) or moderate (FEV1 40-79%, p = 0.0350) groups. MiR-224-5p expression inversely correlated with lung function (FEV1%: r = -0.5944, p = 0.0457) and positively correlated with exacerbation rates (r = 0.6139, p = 0.0370). These data show that peripheral blood monocyte miR-545-5p and miR-224-5p levels correlate with exacerbation rate, whilst miR-224-5p levels also correlate with lung function in cystic fibrosis.

Epigenetic mechanisms underpinning sexual dimorphism in lung disease

Tweetable abstract Important differences in lung disease exist between males and females in symptoms, course of disease and therapeutic response due to molecular, genetic and epigenetic mechanisms related to biological sex.

Research priorities to address the global burden of chronic obstructive pulmonary disease (COPD) in the next decade

Background

The global prevalence of chronic obstructive pulmonary disease (COPD) has increased markedly in recent decades. Given the scarcity of resources available to address global health challenges and respiratory medicine being relatively under-invested in, it is important to define research priorities for COPD globally. In this paper, we aim to identify a ranked set of COPD research priorities that need to be addressed in the next 10 years to substantially reduce the global impact of COPD.

Methods

We adapted the Child Health and Nutrition Research Initiative (CHNRI) methodology to identify global COPD research priorities.

Results

62 experts contributed 230 research ideas, which were scored by 34 researchers according to six pre-defined criteria: answerability, effectiveness, feasibility, deliverability, burden reduction, and equity. The top-ranked research priority was the need for new effective strategies to support smoking cessation. Of the top 20 overall research priorities, six were focused on feasible and cost-effective pulmonary rehabilitation delivery and access, particularly in primary/community care and low-resource settings. Three of the top 10 overall priorities called for research on improved screening and accurate diagnostic methods for COPD in low-resource primary care settings. Further ideas that drew support involved a better understanding of risk factors for COPD, development of effective training programmes for health workers and physicians in low resource settings, and evaluation of novel interventions to encourage physical activity.

Conclusions

The experts agreed that the most pressing feasible research questions to address in the next decade for COPD reduction were on prevention, diagnosis and rehabilitation of COPD, especially in low resource settings. The largest gains should be expected in low- and middle-income countries (LMIC) settings, as the large majority of COPD deaths occur in those settings. Research priorities identified by this systematic international process should inform and motivate policymakers, funders, and researchers to support and conduct research to reduce the global burden of COPD.

Impaired Airway Epithelial Barrier Integrity in Response to Stenotrophomonas maltophilia Proteases, Novel Insights Using Cystic Fibrosis Bronchial Epithelial Cell Secretomics

Stenotrophomonas maltophilia is a Gram-negative opportunistic pathogen that can chronically colonize the lungs of people with cystic fibrosis (CF) and is associated with lethal pulmonary hemorrhage in immunocompromised patients. Its secreted virulence factors include the extracellular serine proteases StmPR1, StmPR2, and StmPR3. To explore the impact of secreted virulence determinants on pulmonary mucosal defenses in CF, we examined the secretome of human CFBE41o- bronchial epithelial cells in response to treatment with S. maltophilia K279a cell culture supernatant (CS) using a liquid-chromatography-tandem mass spectrometry (LC-MS/MS) based label-free quantitative (LFQ) shotgun proteomics approach for global profiling of the cell secretome. Secretome analysis identified upregulated pathways mainly relating to biological adhesion and epithelial cell signaling in infection, whereas no specific pathways relating to the immune response were enriched. Further exploration of the potentially harmful effects of K279a CS on CF bronchial epithelial cells, demonstrated that K279a CS caused CFBE41o- cell condensation and detachment, reversible by the serine protease inhibitor PMSF. K279a CS also decreased trans-epithelial electrical resistance in CFBE41o- cell monolayers suggestive of disruption of tight junction complexes (TJC). This finding was corroborated by an observed increase in fluorescein isothiocyanate (FITC) dextran permeability and by demonstrating PMSF-sensitive degradation of the tight junction proteins ZO-1 and occludin, but not JAM-A or claudin-1. These observations demonstrating destruction of the CFBE41o- TJC provide a novel insight regarding the virulence of S. maltophilia and may explain the possible injurious effects of this bacterium on the CF bronchial epithelium and the pathogenic mechanism leading to lethal pulmonary hemorrhage.

Precise Targeting of miRNA Sites Restores CFTR Activity in CF Bronchial Epithelial Cells

MicroRNAs that are overexpressed in cystic fibrosis (CF) bronchial epithelial cells (BEC) negatively regulate CFTR and nullify the beneficial effects of CFTR modulators. We hypothesized that it is possible to reverse microRNA-mediated inhibition of CFTR using CFTR-specific target site blockers (TSBs) and to develop a drug-device combination inhalation therapy for CF. Lead microRNA expression was quantified in a series of human CF and non-CF samples and in vitro models. A panel of CFTR 3' untranslated region (UTR)-specific locked nucleic acid antisense oligonucleotide TSBs was assessed for their ability to increase CFTR expression. Their effects on CFTR activity alone or in combination with CFTR modulators were measured in CF BEC models. TSB encapsulation in poly-lactic-co-glycolic acid (PLGA) nanoparticles was assessed as a proof of principle of delivery into CF BECs. TSBs targeting the CFTR 3' UTR 298-305:miR-145-5p or 166-173:miR-223-3p sites increased CFTR expression and anion channel activity and enhanced the effects of ivacaftor/lumacaftor or ivacaftor/tezacaftor in CF BECs. Biocompatible PLGA-TSB nanoparticles promoted CFTR expression in primary BECs and retained desirable biophysical characteristics following nebulization. Alone or in combination with CFTR modulators, aerosolized CFTR-targeting TSBs encapsulated in PLGA nanoparticles could represent a promising drug-device combination therapy for the treatment for CFTR dysfunction in the lung.

Plasma microRNA levels in male and female children with cystic fibrosis

A gender gap exists in cystic fibrosis (CF). Here we investigate whether plasma microRNA expression profiles differ between the sexes in CF children. MicroRNA expression was quantified in paediatric CF plasma (n = 12; six females; Age range:1-6; Median Age: 3; 9 p.Phe508del homo- or heterozygotes) using TaqMan OpenArray Human miRNA Panels. Principal component analysis indicated differences in male versus female miRNA profiles. The miRNA array analysis revealed two miRNAs which were significantly increased in the female samples (miR-885-5p; fold change (FC):5.07, adjusted p value: 0.026 and miR-193a-5p; FC:2.6, adjusted p value: 0.031), although only miR-885-5p was validated as increased in females using specific qPCR assay (p < 0.0001). Gene ontology analysis of miR-885-5p validated targets identified cell migration, motility and fibrosis as processes potentially affected, with RAC1-mediated signalling featuring significantly. There is a significant increase in miR-885-5p in plasma of females versus males with CF under six years of age.

The Estrogen-Induced miR-19 Downregulates Secretory Leucoprotease Inhibitor Expression in Monocytes

Compared to females, males are more susceptible to acute viral and other respiratory tract infections that display greater severity and higher mortality. In contrast, females tend to fare worse with chronic inflammatory diseases. Circulating 17β-estradiol (E2) is a female-specific factor that may influence the progression of human lung diseases. Here we hypothesize that E2 modulates the inflammatory response of monocytes through microRNA (miRNA)-based modulation of secretory leucoprotease inhibitor (SLPI), an antiprotease with immunomodulatory effects. Monocytic cells were treated ± E2, and differentially expressed miRNAs were identified using PCR profiling. Cells were transfected with miRNA mimics or antimiRs and SLPI mRNA and protein levels were quantified. Luciferase activity assay using wildtype and ΔmiR-19a/b-SLPI3'UTR reporter constructs and chromatin immunoprecipitation on E2-treated monocytes were performed. E2 downregulated SLPI and upregulated miR-19 expression in monocytes. Transfection with premiR-19b reduced SLPI mRNA and protein levels and this effect was abrogated using antimiRs against miR-19b. miR-19b directly binds the SLPI 3'UTR. The mechanism responsible for E2-mediated upregulation of miR-19 occurs via increased MIR17HG promoter activity mediated by c-MYC. Overall E2 decreases SLPI expression in human monocytic cells, via changes in miRNA expression and highlights the potential for estrogen to modulate the innate immune system.

From the pathophysiology of the human lung alveolus to epigenetic editing: Congress 2018 highlights from ERS Assembly 3 "Basic and Translational Science."

The European Respiratory Society (ERS) International Congress is the largest respiratory congress and brings together leading experts in all fields of respiratory medicine and research. ERS Assembly 3 shapes the basic and translational science aspects of this congress, aiming to combine cutting-edge novel developments in basic research with novel clinical findings. In this article, we summarise a selection of the scientific highlights from the perspective of the three groups within Assembly 3. In particular, we discuss new insights into the pathophysiology of the human alveolus, novel tools in organoid development and (epi)genome editing, as well as insights from the presented abstracts on novel therapeutic targets being identified for idiopathic pulmonary fibrosis.

The amount of basic and translational science presented at #ERSCongress is steadily increasing, showing novel cutting-edge technologies and models.http://bit.ly/2GgXIJi

Systematic evaluation of the microRNAome through miR-CATCHv2.0 identifies positive and negative regulators of BRAF-X1 mRNA

Here we present miR-CATCHv2.0, an implemented experimental method that allows the identification of the microRNA species directly bound to an RNA of interest. After cross-linking of microRNA::RNA::Ago2 complexes using formaldehyde, the RNA is fragmented using sonication and then subjected to affinity purification using two sets of biotinylated tiling probes (ODD and EVEN). Finally, enriched microRNA species are retrieved by means of small RNA sequencing coupled with an ad hoc analytical workflow. In BRAFV600E mutant A375 melanoma cells, miR-CATCHv2.0 allowed us to identify 20 microRNAs that target X1, the most abundant isoform of BRAF mRNA. These microRNAs fall into different functional classes, according to the effect that they exert (decrease/increase in BRAFV600E mRNA and protein levels) and to the mechanism they use to achieve it (destabilization/stabilization of X1 mRNA or decrease/increase in its translation). microRNA-induced variations in BRAFV600E protein levels are most of the times coupled to consistent variations in pMEK levels, in melanoma cell proliferation in vitro and in sensitivity to the BRAF inhibitor vemurafenib in a xenograft model in zebrafish. However, microRNAs exist that uncouple the degree of activation of the ERK pathway from the levels of BRAFV600E protein. Our study proposes miR-CATCHv2.0 as an effective tool for the identification of direct microRNA-target interactions and, by using such a tool, unveils the complexity of the post-transcriptional regulation to which BRAFV600E and the ERK pathway are subjected in melanoma cells.

Nebulised lipid-polymer hybrid nanoparticles for the delivery of a therapeutic anti-inflammatory microRNA to bronchial epithelial cells

Modulation of microRNAs (miRNAs), endogenous regulators of gene expression, is a promising strategy for tackling inflammatory lung diseases. In this proof-of-concept study, we tested delivery of miR-17 to bronchial epithelial cells (BECs) using nebulised lipid-polymer hybrid nanoparticles (LPNs). The primary aim was to reduce the induced secretion of miR-17's target, i.e. the pro-inflammatory chemokine interleukin (IL)-8. Synthetic miR-17 mimics were loaded into LPNs composed of poly(dl-lactic-co-glycolic acid) (PLGA) and the cationic lipid 1,2-dioleoyloxy-3-(trimethylammonium)propane (DOTAP) using a double emulsion solvent evaporation method and nebulised using the Aerogen Solo nebuliser. The physicochemical, aerosol, inflammatory and cytotoxic properties of LPNs were characterised. The effect of LPNs on lipopolysaccharide (LPS)-induced IL-8 production from human NuLi-1 BECs was tested by ELISA. The z-average, polydispersity index and ζ-potential of the LPNs and the aerodynamic properties of nebulised suspensions were in a range optimal for deposition in the bronchi and bronchioles post-inhalation. Cytotoxic and pro-inflammatory effects were minimal for LPNs loaded with a model cargo. Nebulisation did not affect the physicochemical or functional properties of the LPNs. Nebulised miR-17-loaded LPNs downregulated LPS-induced IL-8 secretion by >40% in BECs. This study suggests that DOTAP-modified PLGA LPNs are efficient and well-tolerated carriers for delivery of miRNA mimics to BECs.

Unmasking the pathological and therapeutic potential of histone deacetylases for liver cancer

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, currently ranking as one of the highest neoplastic-related mortalities in the world. Due to the difficulty in early diagnosis and lack of effective treatment options, the 5-year survival rate of HCC remains extremely low. Histone deacetylation is one of the most important epigenetic mechanisms, regulating cellular events such as differentiation, proliferation and cell cycle. Histone deacetylases (HDACs), the chief mediators of this epigenetic mechanism, are often aberrantly expressed in various tumours including HCC. Areas covered: This review focuses on the most up-to-date findings of HDACs and their associated molecular mechanisms in HCC onset and progression. In addition, a potential network between HDACs and non-coding RNAs including microRNAs and long noncoding RNAs underlying hepatocarcinogenesis is considered. Expert opinion: Unmasking the role of HDACs and their association with HCC pathogenesis could have implications for future personalized therapeutic and diagnostic targeting.

Knockdown of Gene Expression in Macrophages by microRNA Mimic-Containing Poly (Lactic-co-glycolic Acid) Microparticles

Background: microRNA (miRNA) regulate target gene expression through translational repression and/or mRNA degradation and are involved in the regulation of inflammation. Macrophages are key inflammatory cells that are important in chronic inflammatory lung diseases such as cystic fibrosis (CF). Macrophage-expressed miRNA represent therapeutic drug targets, yet delivery of nucleic acids to macrophages has proved challenging. Methods: miRNAs were encapsulated in poly (lactic-co-glycolic acid) (PLGA)-based microparticles using double emulsion solvent evaporation and characterised for physicochemical features. Phorbol myristic acetate (PMA)-differentiated U937 macrophages were transfected with empty PLGA microparticles or those encapsulating a premiR-19b-3p or scrambled control miRNA mimic. miRNA internalisation and knockdown of a miR-19b-3p target gene, secretory leucoprotease inhibitor (SLPI), were determined by qRT-PCR. Results: Microparticle formulations were consistently found to be 2⁻3μm and all had a negative ζ potential (-5 mV to -14 mV). Encapsulation efficiency of premiR-19b-3p was 37.6 ± 13.4%. Levels of mature miR-19b-3p were higher in macrophages after delivery of premiR-19b-3p microparticles compared to empty or scrambled control miRNA-containing microparticles. Significant SLPI knockdown was achieved 72 hours post-delivery of premiR-19b-3p microparticles compared to controls. Conclusions: miRNA-encapsulating PLGA microparticles offer a new treatment paradigm for delivery to macrophages that could potentially be administered to CF lungs via inhalation.

Non-coding RNA in cystic fibrosis

Non-coding RNAs (ncRNAs) are an abundant class of RNAs that include small ncRNAs, long non-coding RNAs (lncRNA) and pseudogenes. The human ncRNA atlas includes thousands of these specialised RNA molecules that are further subcategorised based on their size or function. Two of the more well-known and widely studied ncRNA species are microRNAs (miRNAs) and lncRNAs. These are regulatory RNAs and their altered expression has been implicated in the pathogenesis of a variety of human diseases. Failure to express a functional cystic fibrosis (CF) transmembrane receptor (CFTR) chloride ion channel in epithelial cells underpins CF. Secondary to the CFTR defect, it is known that other pathways can be altered and these may contribute to the pathophysiology of CF lung disease in particular. For example, quantitative alterations in expression of some ncRNAs are associated with CF. In recent years, there has been a series of published studies exploring ncRNA expression and function in CF. The majority have focussed principally on miRNAs, with just a handful of reports to date on lncRNAs. The present study reviews what is currently known about ncRNA expression and function in CF, and discusses the possibility of applying this knowledge to the clinical management of CF in the near future.

CFTR dysfunction in cystic fibrosis and chronic obstructive pulmonary disease

INTRODUCTION

Obstructive lung diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are causes of high morbidity and mortality worldwide. CF is a multiorgan genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and is characterized by progressive chronic obstructive lung disease. Most cases of COPD are a result of noxious particles, mainly cigarette smoke but also other environmental pollutants. Areas covered: Although the pathogenesis and pathophysiology of CF and COPD differ, they do share key phenotypic features and because of these similarities there is great interest in exploring common mechanisms and/or factors affected by CFTR mutations and environmental insults involved in COPD. Various molecular, cellular and clinical studies have confirmed that CFTR protein dysfunction is common in both the CF and COPD airways. This review provides an update of our understanding of the role of dysfunctional CFTR in both respiratory diseases. Expert commentary: Drugs developed for people with CF to improve mutant CFTR function and enhance CFTR ion channel activity might also be beneficial in patients with COPD. A move toward personalized therapy using, for example, microRNA modulators in conjunction with CFTR potentiators or correctors, could enhance treatment of both diseases.

Immune function? A missing link in the gender disparity in preterm neonatal outcomes

INTRODUCTION

In neonatology, males exhibit a more severe disease course and poorer prognosis in many pathological states when compared to females. Perinatal brain injury, respiratory morbidity, and sepsis, among other complications, preferentially affect males. Preterm neonates (born <37 weeks gestation) display a particularly marked sexual disparity in pathology, especially at the borders of viability. The sex biases in preterm neonatal outcomes and underlying multifactorial mechanisms have been incompletely explored. Sex-specific clinical phenomena may be partially explained by intrinsic differences in immune function. The distinct immune system of preterm neonates renders this patient population vulnerable, and it is increasingly important to consider biological sex in disease processes and to strive for improved outcomes for both sexes. Areas covered: We discuss the cellular responses and molecular intermediates in immune function which are strongly dependent on sex-specific factors such as the genetic and hormonal milieu of premature birth and consider novel findings in a clinical context. Expert commentary: The role of immune function in the manifestation of sex-specific disease manifestations and outcomes in preterm neonates is a critical prognostic variable. Further mechanistic elucidation will yield valuable translational and clinical information of disease processes in preterm neonates which may be harnessed for modulation.

Gender disparities in preterm neonatal outcomes

AIM

From birth to old age, males generally have poorer disease outcomes compared to females. Preterm infants display a marked gender disparity in disease outcomes, and the underlying mechanisms are not well delineated. Our aim was to review the literature on clinical outcomes between preterm infants of different genders and discuss the potential mechanisms underlying the differences observed.

METHODS

A literature review was undertaken for experimental and clinical research related to gender differences in preterm outcomes.

RESULTS

Preterm male infants appear to have consistently worse outcomes compared to females, and the aetiology of these differences, while mostly undetermined, is likely multifactorial.

CONCLUSION

The male disadvantage in preterm outcomes is likely multifactorial with hormonal, genetic and immunological differences likely playing key roles. Gender is an important variable in preterm outcome and should be considered when designing clinical and experimental research.

Airway Epithelium Dysfunction in Cystic Fibrosis and COPD

Cystic fibrosis is a genetic disease caused by mutations in the CFTR gene, whereas chronic obstructive pulmonary disease (COPD) is mainly caused by environmental factors (mostly cigarette smoking) on a genetically susceptible background. Although the etiology and pathogenesis of these diseases are different, both are associated with progressive airflow obstruction, airway neutrophilic inflammation, and recurrent exacerbations, suggesting common mechanisms. The airway epithelium plays a crucial role in maintaining normal airway functions. Major molecular and morphologic changes occur in the airway epithelium in both CF and COPD, and growing evidence suggests that airway epithelial dysfunction is involved in disease initiation and progression in both diseases. Structural and functional abnormalities in both airway and alveolar epithelium have a relevant impact on alteration of host defences, immune/inflammatory response, and the repair process leading to progressive lung damage and impaired lung function. In this review, we address the evidence for a critical role of dysfunctional airway epithelial cells in chronic airway inflammation and remodelling in CF and COPD, highlighting the common mechanisms involved in the epithelial dysfunction as well as the similarities and differences of the two diseases.

Assembly 3: Basic and Translational Sciences

Assembly 3 is a dynamic and friendly Assembly. In 2017, the Assembly changed its name from “Cell and Molecular Biology” to its current name (Basic and Translational Sciences) to better reflect its activities and focus. We provide a platform for interaction between basic scientists and practising clinicians who are interested in the cellular and molecular mechanisms involved in healthy and diseased lungs. A key focus of our Assembly is tracking scientific developments that easily translate into better diagnostic technologies or enhanced patient care. As such we are centrally involved in devising the content of the Scientific Year in Review and Scientific Grand Round at the ERS International Congress.

Meet @ERStalk Assembly 3: Basic and Translational Scienceshttp://ow.ly/66E830hFi7U

Identification of a novel functional miR-143-5p recognition element in the Cystic Fibrosis Transmembrane Conductance Regulator 3'UTR

MicroRNAs (miRNAs) are small non-coding RNAs involved in regulation of gene expression. They bind in a sequence-specific manner to miRNA recognition elements (MREs) located in the 3' untranslated region (UTR) of target mRNAs and prevent mRNA translation. MiRNA expression is dysregulated in cystic fibrosis (CF), affecting several biological processes including ion conductance in the epithelial cells of the lung. We previously reported that miR-143 is up-regulated in CF bronchial brushings compared to non-CF. Here we identified two predicted binding sites for miR-143-5p (starting at residues 558 and 644) on the CFTR mRNA, and aimed to assess whether CFTR is a true molecular target of miR-143-5p. Expression of miR-143-5p was found to be up-regulated in a panel of CF vs non-CF cell lines (1.7-fold, P = 0.0165), and its levels were increased in vitro after 20 hours treatment with bronchoalveolar lavage fluid from CF patients compared to vehicle-treated cells (3.3-fold, P = 0.0319). Luciferase assays were performed to elucidate direct miRNA::target interactions and showed that miR-143-5p significantly decreased the reporter activity when carrying the wild-type full length sequence of CFTR 3'UTR (minus 15%, P = 0.005). This repression was rescued by the disruption of the first, but not the second, predicted MRE, suggesting that the residue starting at 558 was the actual active binding site. In conclusion, we here showed that miR-143-5p modestly but significantly inhibits CFTR, improving the knowledge on functional MREs within the CFTR 3'UTR. This could lead to the development of novel therapeutic strategies where miRNA-mediated CFTR repression is blocked thereby possibly increasing the efficacy of the currently available CFTR modulators.

Innate Immunity of the Lung: From Basic Mechanisms to Translational Medicine

The respiratory tract is faced daily with 10,000 L of inhaled air. While the majority of air contains harmless environmental components, the pulmonary immune system also has to cope with harmful microbial or sterile threats and react rapidly to protect the host at this intimate barrier zone. The airways are endowed with a broad armamentarium of cellular and humoral host defense mechanisms, most of which belong to the innate arm of the immune system. The complex interplay between resident and infiltrating immune cells and secreted innate immune proteins shapes the outcome of host-pathogen, host-allergen, and host-particle interactions within the mucosal airway compartment. Here, we summarize and discuss recent findings on pulmonary innate immunity and highlight key pathways relevant for biomarker and therapeutic targeting strategies for acute and chronic diseases of the respiratory tract.

Biopolymer-Based Nanoparticles for Cystic Fibrosis Lung Gene Therapy Studies

Lung gene therapy for cystic fibrosis disease has not been successful due to several challenges such as the absence of an appropriate vector. Therefore, optimal delivery of emerging therapeutics to airway epithelial cells demands suitable non-viral systems. In this work, we describe the formulation and the physicochemical investigation of biocompatible and biodegradable polymeric nanoparticles (NPs), including PLGA and chitosan (animal and non-animal), as novel methods for the safe and efficient delivery of CFTR-specific locked nucleic acids (LNAs).

miR-CATCH Identifies Biologically Active miRNA Regulators of the Pro-Survival Gene XIAP, in Chinese Hamster Ovary Cells

Genetic engineering of mammalian cells is of interest as a means to boost bio-therapeutic protein yield. X-linked inhibitor of apoptosis (XIAP) overexpression has previously been shown to enhance CHO cell growth and prolong culture longevity while additionally boosting productivity. The authors confirmed this across a range of recombinant products (SEAP, EPO, and IgG). However, stable overexpression of an engineering transgene competes for the cells translational machinery potentially compromising product titre. MicroRNAs are attractive genetic engineering candidates given their non-coding nature and ability to regulate multiple genes simultaneously, thereby relieving the translational burden associated with stable overexpression of a protein-encoding gene. The large number of potential targets of a single miRNA, falsely predicted in silico, presents difficulties in identifying those that could be useful engineering tools. The authors explored the identification of direct miRNA regulators of the pro-survival endogenous XIAP gene in CHO-K1 cells by using a miR-CATCH protocol. A biotin-tagged antisense DNA oligonucleotide for XIAP mRNA is designed and used to pull down and capture bound miRNAs. Two miRNAs are chosen out of the 14 miRNAs identified for further validation, miR-124-3p and miR-19b-3p. Transient transfection of mimics for both results in the diminished translation of endogenous CHO XIAP protein whereas their inhibition increases XIAP protein levels. A 3'UTR reporter assay confirms miR-124-3p to be a bona fide regulator of XIAP in CHO-K1 cells. This method demonstrates a useful approach to finding miRNA candidates for CHO cell engineering without competing for the cellular translational machinery.

Alpha-1 antitrypsin augmentation therapy decreases miR-199a-5p, miR-598 and miR-320a expression in monocytes via inhibition of NFκB

Alpha-1 antitrypsin (AAT) augmentation therapy involves infusion of plasma-purified AAT to AAT deficient individuals. Whether treatment affects microRNA expression has not been investigated. This study's objectives were to evaluate the effect of AAT augmentation therapy on altered miRNA expression in monocytes and investigate the mechanism. Monocytes were isolated from non-AAT deficient (MM) and AAT deficient (ZZ) individuals, and ZZs receiving AAT. mRNA (qRT-PCR, microarray), miRNA (miRNA profiling, qRT-PCR), and protein (western blotting) analyses were performed. Twenty one miRNAs were differentially expressed 3-fold between ZZs and MMs. miRNA validation studies demonstrated that in ZZ monocytes receiving AAT levels of miR-199a-5p, miR-598 and miR-320a, which are predicted to be regulated by NFκB, were restored to levels similar to MMs. Validated targets co-regulated by these miRNAs were reciprocally increased in ZZs receiving AAT in vivo and in vitro. Expression of these miRNAs could be increased in ZZ monocytes treated ex vivo with an NFκB agonist and decreased by NFκB inhibition. p50 and p65 mRNA and protein were significantly lower in ZZs receiving AAT than untreated ZZs. AAT augmentation therapy inhibits NFκB and decreases miR-199a-5p, miR-598 and miR-320a in ZZ monocytes. These NFκB-inhibitory properties may contribute to the anti-inflammatory effects of AAT augmentation therapy.

Expression of X-linked Toll-like receptor 4 signaling genes in female vs. male neonates

BACKGROUND

Male neonates display poorer disease prognosis and outcomes compared with females. Immune genes which exhibit higher expression in umbilical cord blood (UCB) of females may contribute to the female immune advantage during infection and inflammation. The aim of this study was to quantify expression of Toll-like receptor (TLR) 4 signaling genes encoded on the X-chromosome in UCB from term female vs. male neonates.

METHODS

UCB samples were collected from term neonates (n = 26) born by elective Caesarean section and whole blood was collected from adults (n = 20). Leukocyte RNA was isolated and used in quantitative PCR reactions for IκB kinase γ (IKKγ), Bruton's tyrosine kinase (BTK), and IL-1 receptor associated kinase (IRAK)1. IRAK1 protein was analyzed by Western blot and confocal microscopy.

RESULTS

In neonates there was no significant difference in the relative expression of IKKγ or BTK mRNA between genders. IRAK1 gene and protein expression was significantly higher in female vs. male UCB, with increased cytosolic IRAK1 expression also evident in female UCB mononuclear cells. Adults had higher expression of all three genes compared with neonates.

CONCLUSION

Increased expression of IRAK1 could be responsible, in part, for sex-specific responses to infection and subsequent immune advantage in female neonates.

Identification of MiR-21-5p as a Functional Regulator of Mesothelin Expression Using MicroRNA Capture Affinity Coupled with Next Generation Sequencing

MicroRNAs (miRNAs) are small non-coding RNAs that regulate mRNA expression mainly by silencing target transcripts via binding to miRNA recognition elements (MREs) in the 3'untranslated region (3'UTR). The identification of bona fide targets is challenging for researchers working on the functional aspect of miRNAs. Recently, we developed a method (miR-CATCH) based on biotinylated DNA antisense oligonucleotides that capture the mRNA of interest and facilitates the characterisation of miRNAs::mRNA interactions in a physiological cellular context. Here, the miR-CATCH technique was applied to the mesothelin (MSLN) gene and coupled with next generation sequencing (NGS), to identify miRNAs that regulate MSLN mRNA and that may be responsible for its increased protein levels found in malignant pleural mesothelioma (MPM). Biotinylated MSLN oligos were employed to isolate miRNA::MSLN mRNA complexes from a normal cell line (Met-5A) which expresses low levels of MSLN. MiRNAs targeting the MSLN mRNA were identified by NGS and miR-21-5p and miR-100-5p were selected for further validation analyses. MiR-21-5p was shown to be able to modulate MSLN expression in miRNA mimic experiments in a panel of malignant and non-malignant cell lines. Further miRNA inhibitor experiments and luciferase assays in Mero-14 cells validated miR-21-5p as a true regulator of MSLN. Moreover, in vitro experiments showed that treatment with miR-21-5p mimic reduced proliferation of MPM cell lines. Altogether, this work shows that the miR-CATCH technique, coupled with NGS and in vitro validation, represents a reliable method to identify native miRNA::mRNA interactions. MiR-21-5p is suggested as novel regulator of MSLN with a possible functional role in cellular growth.

microRNA regulatory circuits in a mouse model of inherited retinal degeneration

miRNA dysregulation is a hallmark of many neurodegenerative disorders, including those involving the retina. Up-regulation of miR-1/133 and miR-142, and down-regulation of miR-183/96/182 has been described in the RHO-P347S mouse retina, a model for a common form of inherited blindness. High-throughput LC-MS/MS was employed to analyse the protein expression of predicted targets for these miRNAs in RHO-P347S mouse retinas; 133 potential target genes were identified. Pathway over-representation analysis suggests G-protein signaling/visual transduction, and synaptic transmission for miR-1, and transmembrane transport, cell-adhesion, signal transduction and apoptosis for miR-183/96/182 as regulated functions in retina. Validation of miRNA-target mRNA interactions for miR-1, miR-96/182 and miR-96 targeting Ctbp2, Rac1 and Slc6a9, respectively, was demonstrated in vitro. In vivo interaction of miR-183/96/182 and Rac1 mRNA in retina was confirmed using miR-CATCH. Additional miRNAs (including miR-103-3p, miR-9-5p) were both predicted to target Rac1 mRNA and enriched by Rac1-miR-CATCH. Other Rac1-miR-CATCH-enriched miRNAs (including miR-125a/b-5p, miR-378a-3p) were not predicted to target Rac1. Furthermore, levels of ~25% of the retinal Rac1 interactors were determined by LC-MS/MS; expression of Rap1gds1 and Cav1 was elevated. Our data suggest significant utilisation of miRNA-based regulation in retina. Possibly more than 30 miRNAs interact with Rac1 in retina, targeting both UTRs and coding regions.

Ursodeoxycholic acid inhibits TNFα-induced IL-8 release from monocytes

Monocytes are critical to the pathogenesis of inflammatory bowel disease (IBD) as they infiltrate the mucosa and release cytokines that drive the inflammatory response. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid with anti-inflammatory actions, has been proposed as a potential new therapy for IBD. However, its effects on monocyte function are not yet known. Primary monocytes from healthy volunteers or cultured U937 monocytes were treated with either the proinflammatory cytokine, TNFα (5 ng/ml) or the bacterial endotoxin, lipopolysaccharide (LPS; 1 μg/ml) for 24 h, in the absence or presence of UDCA (25-100 μM). IL-8 release into the supernatant was measured by ELISA. mRNA levels were quantified by qPCR and changes in cell signaling proteins were determined by Western blotting. Toxicity was assessed by measuring lactate dehydrogenase (LDH) release. UDCA treatment significantly attenuated TNFα-, but not LPS-driven, release of IL-8 from both primary and cultured monocytes. UDCA inhibition of TNFα-driven responses was associated with reduced IL-8 mRNA expression. Both TNFα and LPS stimulated NFκB activation in monocytes, while IL-8 release in response to both cytokines was attenuated by an NFκB inhibitor, BMS-345541. Interestingly, UDCA inhibited TNFα-, but not LPS-stimulated, NFκB activation. Finally, TNFα, but not LPS, induced phosphorylation of TNF receptor associated factor (TRAF2), while UDCA cotreatment attenuated this response. We conclude that UDCA specifically inhibits TNFα-induced IL-8 release from monocytes by inhibiting TRAF2 activation. Since such actions would serve to dampen mucosal immune responses in vivo, our data support the therapeutic potential of UDCA for IBD.

Reduced miR-659-3p Levels Correlate with Progranulin Increase in Hypoxic Conditions: Implications for Frontotemporal Dementia

Progranulin (PGRN) is a secreted protein expressed ubiquitously throughout the body, including the brain, where it localizes in neurons and is activated microglia. Loss-of-function mutations in the GRN gene are an important cause of familial frontotemporal lobar degeneration (FTLD). PGRN has a neurotrophic and anti-inflammatory activity, and it is neuroprotective in several injury conditions, such as oxygen or glucose deprivation, oxidative injury, and hypoxic stress. Indeed, we have previously demonstrated that hypoxia induces the up-regulation of GRN transcripts. Several studies have shown microRNAs (miRNAs) involvement in hypoxia. Moreover, in FTLD patients with a genetic variant of GRN (rs5848), the reinforcement of miR-659-3p binding site has been suggested to be a risk factor. Here, we report that miR-659-3p interacts directly with GRN 3′UTR as shown by luciferase assay in HeLa cells and ELISA and Western Blot analysis in HeLa and Kelly cells. Moreover, we demonstrate the physical binding between GRN mRNA and miR-659-3p employing a miRNA capture-affinity technology in SK-N-BE and Kelly cells. In order to study miRNAs involvement in hypoxia-mediated up-regulation of GRN, we evaluated miR-659-3p levels in SK-N-BE cells after 24 h of hypoxic treatment, finding them inversely correlated to GRN transcripts. Furthermore, we analyzed an animal model of asphyxia, finding that GRN mRNA levels increased at post-natal day (pnd) 1 and pnd 4 in rat cortices subjected to asphyxia in comparison to control rats and miR-659-3p decreased at pnd 4 just when GRN reached the highest levels. Our results demonstrate the interaction between miR-659-3p and GRN transcript and the involvement of miR-659-3p in GRN up-regulation mediated by hypoxic/ischemic insults.

Toll-Like Receptors in Cystic Fibrosis: Impact of Dysfunctional microRNA on Innate Immune Responses in the Cystic Fibrosis Lung

Toll-like receptors (TLRs) are a class of pattern recognition receptors that are particularly expressed in the sentinel and epithelial cells in the body, including the lung. They are central players in the innate immune system in response to microbial infection, and are the triggers of a complex pathway network that both promotes the inflammatory response and influences the adaptive immune response. These pathways are transiently and finely tuned by cellular factors, including a cell's microRNA response program. MicroRNAs are small, non-coding RNAs that specifically regulate gene expression. In this article, we review the disease-specific microRNA regulatory network of cystic fibrosis, a debilitating and ultimately fatal disease and, specifically, its effect on TLR signalling.

High-throughput profiling for discovery of non-coding RNA biomarkers of lung disease

In respiratory medicine there is a need for clinical biomarkers for diagnosis, prognosis and assessment of response to therapy. Noncoding RNA (ncRNA) is expressed in all human cells; two major classes--long ncRNA and microRNA--are detectable extracellularly in the circulation and other biofluids. Altered ncRNA expression is associated with lung disease; collectively this indicates that ncRNA represents a potential biomarker class. This article presents and compares existing platforms for detection and quantification of ncRNA, specifically hybridization, qRT-PCR and RNA sequencing, and outlines methods for data interpretation and normalization. Each approach has merits and shortcomings, which can affect the choice of method when embarking on a biomarker study. Biomarker properties and pre-analytical considerations for ncRNA profiling are also presented. Since a variety of profiling approaches are available, careful study and experimental design are important. Finally, challenges and goals for reliable, standardized high-throughput ncRNA profiling in biofluids as lung disease biomarkers are reviewed.

The Role of Short-Chain Fatty Acids, Produced by Anaerobic Bacteria, in the Cystic Fibrosis Airway

RATIONALE

Anaerobic bacteria are present in large numbers in the airways of people with cystic fibrosis (PWCF). In the gut, anaerobes produce short-chain fatty acids (SCFAs) that modulate immune and inflammatory processes.

OBJECTIVES

To investigate the capacity of anaerobes to contribute to cystic fibrosis (CF) airway pathogenesis via SCFAs.

METHODS

Samples of 109 PWCF were processed using anaerobic microbiological culture with bacteria present identified by 16S RNA sequencing. SCFA levels in anaerobic supernatants and bronchoalveolar lavage (BAL) were determined by gas chromatography. The mRNA and/or protein expression of two SCFA receptors, GPR41 and GPR43, in CF and non-CF bronchial brushings and 16HBE14o(-) and CFBE41o(-) cells were evaluated using reverse transcription polymerase chain reaction, Western blot analysis, laser scanning cytometry, and confocal microscopy. SCFA-induced IL-8 secretion was monitored by ELISA.

MEASUREMENTS AND MAIN RESULTS

Fifty-seven (52.3%) of 109 PWCF were anaerobe positive. Prevalence increased with age, from 33.3% to 57.7% in PWCF younger (n = 24) and older (n = 85) than 6 years of age. All evaluated anaerobes produced millimolar concentrations of SCFAs, including acetic, propionic, and butyric acids. SCFA levels were higher in BAL samples of adults than in those of children. GPR41 levels were elevated in CFBE41o(-) versus 16HBE14o(-) cells; CF versus non-CF bronchial brushings; and 16HBE14o(-) cells after treatment with cystic fibrosis transmembrane conductance regulator inhibitor CFTR(inh)-172, CF BAL, or inducers of endoplasmic reticulum stress. SCFAs induced a dose-dependent and pertussis toxin-sensitive IL-8 response in bronchial epithelial cells, with a higher production of IL-8 in CFBE41o(-) than in 16HBE14o(-) cells.

CONCLUSIONS

This study illustrates that SCFAs contribute to excessive production of IL-8 in CF airways colonized with anaerobes via up-regulated GPR41.

Sexual maturation protects against development of lung inflammation through estrogen

Increasing levels of estrogen and progesterone are suggested to play a role in the gender switch in asthma prevalence during puberty. We investigated whether the process of sexual maturation in mice affects the development of lung inflammation in adulthood and the contributing roles of estrogen and progesterone during this process. By inducing ovalbumin-induced lung inflammation in sexually mature and immature (ovariectomized before sexual maturation) adult mice, we showed that sexually immature adult mice developed more eosinophilic lung inflammation. This protective effect of "puberty" appears to be dependent on estrogen, as estrogen supplementation at the time of ovariectomy protected against development of lung inflammation in adulthood whereas progesterone supplementation did not. Investigating the underlying mechanism of estrogen-mediated protection, we found that estrogen-treated mice had higher expression of the anti-inflammatory mediator secretory leukoprotease inhibitor (SLPI) and lower expression of the proasthmatic cytokine IL-33 in parenchymal lung tissue and that their expressions colocalized with type II alveolar epithelial cells (AECII). Treating AECII directly with SLPI significantly inhibited IL-33 production upon stimulation with ATP. Our data suggest that estrogen during puberty has a protective effect on asthma development, which is accompanied by induction of anti-inflammatory SLPI production and inhibition of proinflammatory IL-33 production by AECII.

The basophil surface marker CD203c identifies Aspergillus species sensitization in patients with cystic fibrosis

BACKGROUND

Colonization by Aspergillus fumigatus in patients with cystic fibrosis (CF) can cause A fumigatus sensitization and/or allergic bronchopulmonary aspergillosis (ABPA), which affects pulmonary function and clinical outcomes. Recent studies show that specific allergens upregulate the surface-expressed basophil marker CD203c in sensitized subjects, a response that can be readily measured by using flow cytometry.

OBJECTIVE

We sought to identify A fumigatus sensitization in patients with CF by using the basophil activation test (BAT).

METHODS

Patients with CF attending Beaumont Hospital were screened for study inclusion. BAT was used to identify A fumigatus sensitization. Serologic (total and A fumigatus-specific IgE), pulmonary function, and body mass index measurements were performed.

RESULTS

The BAT discriminates A fumigatus-sensitized from nonsensitized patients with CF. Persistent isolation of A fumigatus in sputum is a significant risk factor for A fumigatus sensitization. Levels of the A fumigatus-stimulated basophil activation marker CD203c inversely correlated with pulmonary function and body mass index in A fumigatus-sensitized but not nonsensitized patients with CF. Total and A fumigatus-specific IgE, but not IgG, levels are increased in A fumigatus-sensitized patients with CF and ABPA when compared with those in A fumigatus-sensitized and nonsensitized patients with CF without ABPA. Itraconazole treatment did not affect A fumigatus sensitization.

CONCLUSION

Combining the BAT with routine serologic testing allows classification of patients with CF into 3 groups: nonsensitized, A fumigatus-sensitized, and ABPA. Accurate and prompt identification of A fumigatus-associated clinical status might allow early and targeted therapeutic intervention, potentially improving clinical outcomes.