Overexpression of miR-125b, a novel regulator of innate immunity, in eosinophilic chronic rhinosinusitis with nasal polyps

Advances in noncoding RNA in children allergic rhinitis

BACKGROUND

A chronic condition that significantly reduces a child's quality of life is allergic rhinitis (AR). The environment and allergens that the body is regularly exposed to can cause inflammatory and immunological reactions, which can change the expression of certain genes Epigenetic changes are closely linked to the onset and severity of allergy disorders according to mounting amounts of data. Noncoding RNAs (ncRNAs) are a group of RNA molecules that cannot be converted into polypeptides. The three main categories of ncRNAs include microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). NcRNAs play a crucial role in controlling gene expression and contribute to the development of numerous human diseases.

METHODS

Articles are selected based on Pubmed's literature review and the author's personal knowledge. The largest and highest quality studies were included. The search selection is not standardized.

RESULTS

Recent findings indicate that various categories of ncRNAs play distinct yet interconnected roles and actively contribute to intricate gene regulatory networks.

CONCLUSION

This article demonstrates the significance and progress of ncRNAs in children's AR. The database covers three key areas: miRNAs, lncRNAs, and circRNAs. Additionally, potential avenues for future research to facilitate the practical application of ncRNAs as therapeutic targets and biomarkers will be explore.

Ketogenic Diet Induced Shifts in the Gut Microbiome Associate with Changes to Inflammatory Cytokines and Brain-Related miRNAs in Children with Autism Spectrum Disorder

In this interventional pilot study, we investigated the effects of a modified ketogenic diet (KD) on children with autism spectrum disorder (ASD). We previously observed improved behavioral symptoms in this cohort following the KD; this trial was registered with Clinicaltrials.gov (NCT02477904). This report details the alterations observed in the microbiota, inflammation markers, and microRNAs of seven children following a KD for a duration of 4 months. Our analysis included blood and stool samples, collected before and after the KD. After 4 months follow up, we found that the KD led to decreased plasma levels of proinflammatory cytokines (IL-12p70 and IL-1b) and brain-derived neurotrophic factor (BDNF). Additionally, we observed changes in the gut microbiome, increased expression of butyrate kinase in the gut, and altered levels of BDNF-associated miRNAs in the plasma. These cohort findings suggest that the KD may positively influence ASD sociability, as previously observed, by reducing inflammation, reversing gut microbial dysbiosis, and impacting the BDNF pathway related to brain activity.

MicroRNA-125b Is a Potential Predictor of Surgical Outcomes in Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

Despite advances in surgical techniques, recurrence rates after endoscopic sinus surgery (ESS) for chronic rhinosinusitis with nasal polyps (CRSwNP) remain high and difficult to predict.

OBJECTIVE

This study aimed to evaluate the potential role of microRNA 125b (miR-125b) in predicting disease evolution following ESS.

METHODS

We conducted a prospective study including patients undergoing first ESS for CRSwNP in our department between January 2020 and November 2021. We determined miR-125b levels from nasal polyps and pursued a standardized follow-up for at least 18 months for each patient.

RESULTS

A total of 86 patients were included in the study. Higher postoperative endoscopy scores were associated with more severe disease at presentation on computed tomography scan, presence of concomitant asthma, and higher values of miR-125b. Even after multivariate repeated measures analysis and adjustments for confounders, miR-125b remained statistically significant. Moreover, miR-125 was the most important factor in predicting disease evolution at 18 months.

CONCLUSION

A clear, robust relation between nasal polyp control evaluated through objective measures and miR-125b values was observed. This finding indicates the potential role of miR-125b in predicting the course of the disease following ESS.

Genome-wide Epigenetic Study of Chronic Rhinosinusitis Tissues Reveals Dysregulated Inflammatory, Immunologic and Remodeling Pathways

BACKGROUND

Epigenetics studies mechanisms such as DNA methylation, histone modifications, non-coding RNAs, and alternative polyadenylation that can modify gene activity without changing the underlying DNA nucleotide base-pair structure. Because these changes are reversible, they have potential in developing novel therapeutics. Currently, seven pharmaceutical agents targeting epigenetic changes are FDA approved and commercially available for treatment of certain cancers. However, studies investigating epigenetics in chronic rhinosinusitis (CRS) have not been undertaken previously in the United States.

OBJECTIVES

The goal of this study was to investigate sinonasal DNA methylation patterns in CRS versus controls, to discern environmentally-induced epigenetic changes impacting CRS subjects.

METHODS AND RESULTS

Ethmoidal samples from CRS and inferior turbinate mucosal tissue samples from controls without CRS were studied. DNA methylation was studied by Reduced Representation Bisulfite Sequencing. RADMeth® biostatistical package was used to identify differentially methylated regions (DMRs) between CRS and controls. Ingenuity Pathway analysis of DMRs was performed to identify top upstream regulators and canonical pathways. Ninety-three samples from 64 CRS subjects (36 CRSwNP; 28 CRSsNP) and 29 controls were studied. CRS and control samples differed in 13 662 CpGs sites and 1381 DMRs. Top upstream regulators identified included: 1. CRS versus controls: TGFB1, TNF, TP53, DGCR8, and beta-estradiol. 2. CRSwNP versus controls: TGFB1, CTNNB1, lipopolysaccharide, ID2, and TCF7L2. 3. CRSsNP versus controls: MYOD1, acetone, ID2, ST8SIA4, and LEPR.

CONCLUSIONS

Differential patterns of methylation were identified between controls and CRS, CRSwNP, and CRSsNP. Epigenetic, environmentally-induced changes related to novel, inflammatory, immunologic, and remodeling pathways appear to affect epithelial integrity, cell proliferation, homeostasis, vascular permeability, and other yet uncharacterized pathways and genes.

Can EPOS2020 criteria of type 2 inflammation be applied to Asian patients with chronic rhinosinusitis?

BACKGROUND

There is a large diversity of mucosal immunologic chronic rhinosinusitis with nasal polyps (CRSwNP) endotypes across Western and Asian patient populations.

OBJECTIVES

The objective of the study was whether the European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) 2020 criteria for type 2 inflammation are appropriate for biological use in CRSwNP patients.

METHODS

A total of 207 participants are enrolled for the study. Retrospective evaluations of the tissues taken during surgery and the patients' clinical features were performed. We investigated whether the criteria described in the EPOS2020 guideline were appropriate based on the criteria for type 2 inflammation identified based on prior studies using receiver-operating characteristic (ROC) analyses.

RESULTS

The EPOS 2020 criteria are also shown to be an insufficient evaluation approach with low specificity (area under curve [AUC] = 0.645, specificity 8.4%). The authors created a novel scoring method using the total serum IgE level, blood eosinophil percentage, and tissue eosinophil percentage. This novel scoring system (AUC = 0.862, p < .001) fared better in ROC analyses than the EPOS 2020 criteria (AUC = 0.645) and Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis scoring system (AUC = 0.647).

CONCLUSIONS AND SIGNIFICANCE

A novel standard for type 2 inflammation in Asian CRSwNP patients must be established, as the EPOS 2020 criteria do not appear to be sufficient.

Epithelial cell dysfunction in chronic rhinosinusitis: the epithelial-mesenchymal transition

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is a type of epithelial cell dysfunction, which is widely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS), especially CRS with nasal polyps, and contributes to pathogenesis of the disease. EMT is mediated via complex mechanisms associated with multiple signaling pathways.

AREAS COVERED

We have summarized the underlying mechanisms and signaling pathways promoting EMT in CRS. Strategies or drugs/agents targeting the genes and pathways related to the regulation of EMT are also discussed for their potential use in the treatment of CRS and asthma. A literature search of studies published in English from 2000 to 2023 was conducted using the PubMed database, employing CRS, EMT, signaling, mechanisms, targeting agents/drugs, as individual or combinations of search terms.

EXPERT OPINION

EMT in nasal epithelium not only leads to epithelial cell dysfunction but also plays an important role in nasal tissue remodeling in CRS. A comprehensive understanding of the mechanisms underlying EMT and the development of drugs/agents targeting these mechanisms may provide new treatment strategies for CRS.

Insights into the epigenetics of chronic rhinosinusitis with and without nasal polyps: a systematic review

Background

Epigenetics facilitates insights on the impact of host environment on the genesis of chronic rhinosinusitis (CRS) through modulations of host gene expression and activity. Epigenetic mechanisms such as DNA methylation cause reversible but heritable changes in gene expression over generations of progeny, without altering the DNA base-pair sequences. These studies offer a critical understanding of the environment-induced changes that result in host predisposition to disease and may help in developing novel biomarkers and therapeutics. The goal of this systematic review is to summarize the current evidence on epigenetics of CRS with a focus on chronic rhinosinusitis with nasal polyps (CRSwNP) and highlight gaps that merit further research.

Methods

A systematic review of the English language literature was performed to identify investigations related to epigenetic studies in subjects with CRS.

Results

The review identified 65 studies. These have focused on DNA methylation and non-coding RNAs, with only a few on histone deacetylation, alternative polyadenylation, and chromatin accessibility. Studies include those investigating in vivo and in vitro changes or both. Studies also include animal models of CRS. Almost all have been conducted in Asia. The genome-wide studies of DNA methylation found differences in global methylation between CRSwNP and controls, while others specifically found significant differences in methylation of the CpG sites of the thymic stromal lymphopoietin (TSLP), IL-8, and PLAT. In addition, DNA methyltransferase inhibitors and histone deacetylase inhibitors were studied as potential therapeutic agents. Majority of the studies investigating non-coding RNAs focused on micro-RNAs (miRNA) and found differences in global expression of miRNA levels. These studies also revealed some previously known as well as novel targets and pathways such as tumor necrosis factor alpha, TGF beta-1, IL-10, EGR2, aryl hydrocarbon receptor, PI3K/AKT pathway, mucin secretion, and vascular permeability. Overall, the studies have found a dysregulation in pathways/genes involving inflammation, immune regulation, tissue remodeling, structural proteins, mucin secretion, arachidonic acid metabolism, and transcription.

Conclusions

Epigenetic studies in CRS subjects suggest that there is likely a major impact of the environment. However, these are association studies and do not directly imply pathogenesis. Longitudinal studies in geographically and racially diverse population cohorts are necessary to quantify genetic vs. environmental risks for CRSwNP and CRS without nasal polyps and assess heritability risk, as well as develop novel biomarkers and therapeutic agents.

MicroRNAs: Potential Biomarkers of Disease Severity in Chronic Rhinosinusitis with Nasal Polyps

Background and Objectives: Chronic rhinosinusitis with nasal polyps (CRwNP) has multiple clinical presentations, and predictors of successful treatment are correlated to different parameters. Differentially expressed microRNAs in nasal polyps emerge as possible facilitators of precise endotyping in this disease. We aimed to evaluate the correlation between the clinical parameters of CRSwNP and two different microRNAs. Materials and Methods: The expression of miR-125b and miR-203a-3p in nasal polyps (n = 86) and normal nasal mucosa (n = 20) was determined through microarray analysis. Preoperative workup included CT scan, nasal endoscopy, blood tests, symptoms and depression questionnaires. Results: MiR-125b showed significant overexpression in NP compared to the normal nasal mucosa. miR-125b expression levels were positively and significantly correlated with blood eosinophilia (p = 0.018) and nasal endoscopy score (p = 0.021). Although high CT scores were related to miR-125b overexpression, the correlation did not reach statistical significance. miR-203a-3p was underexpressed in nasal polyps and was significantly underexpressed in CRSwNP patients with environmental allergies. Conclusions: Both miR-125b and miR-203a-3p are potential biomarkers in CRSwNP. miR-125b also correlates with the clinical picture, while miR-203a-3p could help identify an associated allergy.

Genetics and epigenetics of chronic rhinosinusitis

Discerning the genetics and epigenetics of chronic rhinosinusitis (CRS) may optimize outcomes through early diagnostics, personalized and novel therapeutics, and early prognostication. CRS associated with cystic fibrosis and primary ciliary dyskinesia has well-characterized genetic mutations. Most CRS subjects, however, do not exhibit identifiable monogenic alterations. Clustering in related individuals is seen in CRS with nasal polyps. Spouses of subjects with CRS without nasal polyps also may be at increased risk of the same disease. These observations generate questions on genetic and environmental influences in CRS. Genome-wide association studies have identified variations and polymorphisms between CRS and control subjects in genes related to innate and adaptive immunity. Candidate gene and transcriptomics studies have investigated and identified genetic variations related to immunity, inflammation, epithelial barrier function, stress-response, antigen processing, T-cell regulation, and cytokines in CRS. Epigenetic studies have identified mechanisms through which environmental factors may affect these gene functions. However, causality is not determined for most variations. Inferences drawn from these data must be measured because most investigations report unreplicated results from small study populations. Large, replicated studies in tight cohorts across diverse populations remain a pressing need in studying CRS genetics.

Epigenetic modifications in chronic rhinosinusitis with and without nasal polyps

Chronic rhinosinusitis (CRS) has brought a huge socioeconomic burden. However, its mechanism is still elusive, which may involve genetic, environmental and some other factors. Epigenetic analyses have been conducted to explore the mechanisms underlying CRS. Here, we reviewed the fruits in the epigenetic studies on DNA methylation, histone modification, and non-coding RNA regulation. We concluded that the epigenetic research on CRS has made great breakthroughs, especially in the past 5 years and the field of microRNAs. "Epigenetic therapies" are expected to be designed to treat CRS in the future.

MicroRNA-21-5p promotes mucosal type 2 inflammation via regulating GLP1R/IL-33 signaling in chronic rhinosinusitis with nasal polyps

BACKGROUND

It has been known that chronic rhinosinusitis with nasal polyps (CRSwNP) is a type 2 inflammation-dominated disease; however, the reasons causing such type of mucosal inflammation in CRSwNP are not well elucidated.

OBJECTIVE

We sought to investigate the role of microRNA-21-5p (miR-21-5p) in regulating mucosal type 2 inflammation in CRSwNP.

METHODS

miR-21-5p expression was detected in nasal mucosa of patients with CRSwNP. Correlations between miR-21-5p and indicators of type 2 inflammation were further analyzed. miR-21 knockout mice were used to explore the role of miR-21-5p in a murine model of eosinophilic (E) CRSwNP. Target gene of miR-21-5p related to type 2 inflammation in CRSwNP was identified.

RESULTS

The upregulated miR-21-5p in the nasal mucosa of patients with CRSwNP, compared with control subjects, was expressed higher in patients with ECRSwNP than in patients with nonECRSwNP. miR-21-5p expression was positively correlated with mucosal eosinophil infiltrations and the expression of type 2 inflammatory cytokines. In the CRSwNP mice, miR-21 knockout significantly attenuated type 2 inflammation, as indicated by eosinophil infiltrations and expression of cytokines/chemokines in nasal mucosa and lavage fluid; moreover, genes associated with type 2 inflammation were extensively downregulated at the transcriptome level in miR-21 knockout mice. Glucagon-like peptide-1 receptor, which was negatively correlated with miR-21-5p expression in human nasal mucosa, was identified as the target of miR-21-5p. Overexpression of miR-21-5p induced IL-33 expression, whereas glucagon-like peptide-1 receptor agonist decreased IL-33 production in airway epithelial cells.

CONCLUSIONS

miR-21-5p aggravates type 2 inflammation in the nasal mucosa of patients with CRSwNP via targeting glucagon-like peptide-1 receptor/IL-33 signaling, which may be a potential therapeutic target for CRSwNP.

Immunological Aspects of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is related to persistent inflammation with a dysfunctional relationship between environmental agents and the host immune system. Disturbances in the functioning of the sinus mucosa lead to common clinical symptoms. The major processes involved in the pathogenesis of CRS include airway epithelial dysfunctions that are influenced by external and host-derived factors which activate multiple immunological mechanisms. The molecular bases for CRS remain unclear, although some factors commonly correspond to the disease: bacterial, fungal and viral infections, comorbidity diseases, genetic dysfunctions, and immunodeficiency. Additionally, air pollution leads increased severity of symptoms. CRS is a heterogeneous group of sinus diseases with different clinical courses and response to treatment. Immunological pathways vary depending on the endotype or genotype of the patient. The recent knowledge expansion into mechanisms underlying the pathogenesis of CRS is leading to a steadily increasing significance of precision medicine in the treatment of CRS. The purpose of this review is to summarize the current state of knowledge regarding the immunological aspects of CRS, which are essential for ensuring more effective treatment strategies.

Roles of Exosomes in Chronic Rhinosinusitis: A Systematic Review

The pathophysiology of chronic rhinosinusitis (CRS) is multifactorial and not entirely clear. The objective of the review was to examine the current state of knowledge concerning the role of exosomes in CRS. For this systematic review, we searched PubMed/MEDLINE, Scopus, CENTRAL, and Web of Science databases for studies published until 7 August 2022. Only original research articles describing studies published in English were included. Reviews, book chapters, case studies, conference papers, and opinions were excluded. The quality of the evidence was assessed with the modified Office and Health Assessment and Translation (OHAT) Risk of Bias Rating Tool for Human and Animal Studies. Of 250 records identified, 17 were eligible, all of which had a low to moderate risk of overall bias. Presented findings indicate that exosomal biomarkers, including proteins and microRNA, act as promising biomarkers in the diagnostics and prognosis of CRS patients and, in addition, may contribute to finding novel therapeutic targets. Exosomes reflecting tissue proteomes are excellent, highly available material for studying proteomic alterations noninvasively. The first steps have already been taken, but more advanced research on nasal exosomes is needed, which might open a wider door for individualized medicine in CRS.

Construction and analysis of a ceRNA network and patterns of immune infiltration in chronic rhinosinusitis with nasal polyps: based on data mining and experimental verification

Recent studies have revealed the significant role of the competing endogenous RNA (ceRNA) network in human diseases. However, systematic analysis of the ceRNA mechanism in chronic rhinosinusitis with nasal polyps (CRSwNP) is limited. In this study, we constructed a competitive endogenous RNA (ceRNA) network and identified a potential regulatory axis in CRSwNP based on bioinformatics analysis and experimental verification. We obtained lncRNA, miRNA, and mRNA expression profiles from the Gene Expression Omnibus. After analysis of CRSwNP patients and the control groups, we identified 565 DE-lncRNAs, 23 DE-miRNAs, and 1799 DE-mRNAs by the DESeq2 R package or limma R package. Enrichment analysis of 1799 DE-mRNAs showed that CRSwNP was associated with inflammation and immunity. Moreover, we identified 21 lncRNAs, 8 miRNAs and 8 mRNAs to construct the lncRNA-miRNA-mRNA ceRNA network. A potential MIAT/miR-125a/IRF4 axis was determined according to the degree and positive correlation between a lncRNA and its competitive endogenous mRNAs. The GSEA results suggested that IRF4 may be involved in immune cell infiltration. The validation of another dataset confirmed that MIAT and IRF4 were differentially expressed between the CRSwNP and control groups. The area under the ROC curve (AUC) of MIAT and IRF4 was 0.944. The CIBERSORT analysis revealed that eosinophils and M2 macrophages may be involved in the CRSwNP process. MIAT was correlated with dendritic cells and M2 macrophages, and IRF4 was correlated with dendritic cells. Finally, to validate the key genes, we performed in-silico validation using another dataset and experimental validation using immunohistochemistry, immunofluorescence, and Western blot. In summary, the constructed novel MIAT/miR-125a/IRF4 axis may play a critical role in the development and progression of CRSwNP. We believe that the ceRNA network and immune cell infiltration could offer further insight into novel molecular therapeutic targets for CRSwNP.

Expression of Apoptosis-Related Biomarkers in Inflamed Nasal Sinus Epithelium of Patients with Chronic Rhinosinusitis with Nasal Polyps (CRSwNP)—Evaluation at mRNA and miRNA Levels

In chronic upper respiratory tract diseases, increased cell proliferative activity is observed, which is coordinated by BCL-2 proteins and small non-coding RNAs. This study aimed to determine the expression of critical apoptosis markers at the mRNA and miRNA levels in patients with chronic rhinosinusitis with nasal polyps (CSRwNP). The study group consisted of ten patients with CSRwNP and ten healthy subjects. To detect in situ apoptosis in the maxillary sinus mucosa, TUNEL staining was performed. The expression of transcripts was determined by RT-qPCR and included the detection of markers associated with cell survival and apoptosis, i.e., BAX, p53, p21, CASP3, CASP9, c-MYC, CCND1, BRIC5, and APAF1. Levels of miR-17-5p, miR-145-5p, miR-146a-5p, and miR-203a-3p were also measured by RT-qPCR. The obtained results indicated increased apoptosis determined by a TUNEL assay in CSRwNP patients and accompanied by an increased expression of BAX, P21, P53, CASP3, CASP9, c-MYC, and APAF-1 transcripts and decreased mRNA levels of BCL-2 and BIRC5. Furthermore, the nasal sinus epithelium of patients with CSRwNP showed increased levels of miR-203a-3p while also showing a decreased expression of miR-17-5p and miR-145-5p. Our results showed that pro-apoptotic transcripts detected at mRNA and miRNA levels might be involved in the pathogenesis of chronic sinusitis with polyps. The identification of those key molecular mediators may be applicable for the specific diagnostic and/or development of targeted therapies for chronic sinusitis with polyps.

The hMeDIP-Seq identified INPP4A as a novel biomarker for eosinophilic chronic rhinosinusitis with nasal polyps

Background: Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) is an endotype of chronic rhinosinusitis with nasal polyps characterized by more severe symptoms, a stronger association with asthma and a greater recurrence risk. It is unknown whether DNA hydroxymethylation could influence ECRSwNP. Methods: Hydroxymethylated DNA immunoprecipitation sequencing was carried out in three distinct groups (control, ECRSwNP and NECRSwNP). Additional qRT-PCR, immunohistochemistry and analysis of the receiver operating characteristic curve were performed. Results: Between ECRSwNP and NECRSwNP, 26 genes exhibited differential DNA hydroxymethylation. Consistent with their hydroxymethylation level, GNAL, INPP4A and IRF4 expression levels were significantly different between ECRSwNP and the other two groups. The receiver operating characteristic curve revealed that INPP4A mRNA has a high predictive accuracy for ECRSwNP. Conclusion: DNA hydroxymethylation regulates the expression of multiple genes in ECRSwNP. INPP4A mRNA was markedly decreased in ECRSwNP polyps and can predict ECRSwNP.

Phosphatidylethanolamine-binding protein 1 (PEBP1) mediates the regulatory role of microRNAs (miRNAs)-205-5p in degranulation and histamine release

miR-205-5p plays a vital role in the inflammation of allergic rhinitis (AR). The study is designed to investigate the effects and mechanism of miR-205-5p in AR in vivo and in vitro. An OVA-induced mice model and anti-DNP IgE-induced RBL-2H3 cell model were established. The pathological alterations in the nasal mucosa were evaluated by hematoxylin-eosin (HE) staining. IgE and histamine levels were detected by corresponding kits and the expressions of PEBP1, High mobility group box-1 (HMGB1) and Toll-like receptor 4 (TLR4) were detected by western blot. The association of miR-205-5p and PEBP1 was determined by dual-luciferase reported assay. β-hexosaminidase activity was to evaluate the degranulation of RBL-2H3 cell. The pathological injury of nasal mucosa was significantly improved by miR-205-5p inhibition compared to AR mice. Following the treatment of miR-205-5p inhibitor, the levels of helper T cell (Th1) cytokines, interleukin (IL)-2 and interferon-γ (IFN-γ) were increased, while the levels of Th2 cytokines, IL-4 and IL-13, as well as the levels of IgE and histamine were markedly decreased in AR mice. We further found that miR-205-5P inhibition induced increased expression of PEBP1 and decreased expressions of HMGB1and TLR4. In vitro, miR-205-5P was verified to bind to PEBP1. PEBP1 silencing led to the reverse of miR-205-5p effects on decreasing the levels of β-hexosaminidase activity and histamine, as well as the expressions of HMGB1 and TLR4 on anti-DNP IgE-induced RBL-2H3 cells. Our results indicate that miR-205-5P inhibition may ameliorate pathological injury via PEBP1. MiR-205-5P/ PEBP1 could be potential drug targets in AR

Identification of lncRNA Biomarkers and LINC01198 Promotes Progression of Chronic Rhinosinusitis with Nasal Polyps through Sponge miR-6776-5p

Background

Chronic sinusitis (CRS) was a chronic inflammation that originated in the nasal mucosa and affected the health of most people around the world. Chronic rhinosinusitis with nasal polyps (CRSwNP) was one kind of chronic sinusitis. Emerging research had suggested that long noncoding RNAs (lncRNAs) played vital parts in inflammatories and inflammation development.

Methods

We acquired GEO data to analyze the differential expression between the miRNA, immune genes, TF, and lncRNA data in CRSWNP and the corresponding control tissues. Bioinformatic analysis by coexpression of endogenous RNA network and competitive way enrichment, analysis, and forecasting functions of these noncoding RNA. The different pathway expressions in CRSwNP patients were confirmed using GSVA to analyze the differentially expressed immune genes and TF data sets in CRSwNP patients. The differential immune gene and transcription factor data set in CRSwNP perform functional notes and protein-protein interaction (PPI) network structure. We predicted the potential genes and RNAs related to CRSWNP by constructing a ceRNA network. In addition, we also used 19 hub immune genes to predict the potential drugs of CRSWNP. lncRNA biomarkers in CRSwNP were identified by lncRNAs LASSO regression. The CIBERSORT algorithm was used to contrast the divergence in immune infiltrations between CRSwNP and usual inferior turbinate organizations in 22 immunocyte subgroups.

Results

We identified a total of 48 miRNAs, 304 lncRNAs, 92 TFs, and 525 immune genes as CRSwNP-specific RNAs. GO and KEGG pathways both analyzed differentially expressed immune genes and transcription factor data sets. We predicted the potential genes GNG7, TUSC8, LINC01198, and has-miR-6776-5p by constructing ceRNA and PPI networks. At the same time, we found that the above genes were involved in two important pathways: chemokine signal path and PI3K/AKT signal path. In addition, we predicted 5 small molecule drugs to treat CRSwNP by analyzing 19 central immune genes, namely, danazol, ikarugamycin, semustine, cefamandole, and molindone. Finally, we identified 5 biomarkers in CRSwNP, namely, LINC01198, LINC01094, LINC01798, LINC01829, and LINC01320.

Conclusions

We had identified CRSwNP-related miRNAs, lncRNAs, TFs, and immune genes, which may be making use of latent therapeutic target for CRSwNP. At the same time, we identified 5 lncRNA biomarkers in CRSwNP. The results of this study showed that LINC01198 promoted the progression of CRSwNPs through spongy miR-6776-5p. Our studies provide a new way for further analyses of the pathogenesis of CRSwNP.

Differential expression profile of plasma exosomal microRNAs in chronic rhinosinusitis with nasal polyps

Exosomes mediate inflammation and immune responses. The aim of the study was to examine the expression profiles of plasma exosomal microRNAs (miRNAs) and analyze their target gene functions in participants with chronic rhinosinusitis with nasal polyps (CRSwNP). We measured plasma exosomal miRNAs in five patients with CRSwNP and five controls. Transcripts per million (TPM) was used to assess miRNAs expression and the Benjamini-Hochberg procedure was employed for multiple comparisons correction. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene ontology (GO) analyses revealed biological annotation and functional prediction of target genes. Compared with controls, we found that 159 exosomal miRNAs were differentially expressed by miRNA sequencing in CRSwNP. The top three upregulated miRNAs were novel_miR_677, novel_miR_1037, and novel_miR_79, while the top three downregulated miRNAs were novel_miR_192, novel_miR_1022, and novel_miR_4. The target functions in the GO and KEGG analyses included axon guidance, extracellular matrix (ECM)-receptor interaction, protein digestion and absorption, the calcium, the Hippo, the Notch, the ErbB, the cAMP signaling pathway, and focal adhesion. This study describes the dissection of plasma exosomal miRNA profiling in CRSwNP. Our findings may provide a certain basis for further mechanism research and exploration of diagnostic values.

Analysis of competing endogenous RNA (ceRNA) crosstalk in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is one of the most common chronic inflammatory diseases, and has various phenotypes. Although its pathophysiology remains obscure, evidence has shown that dysregulation of noncoding RNAs (ncRNAs) is associated with CRSwNP. ncRNAs in the cytoplasm can act as competing endogenous RNAs (ceRNAs), which are involved in many inflammatory processes. However, the ceRNA crosstalk in CRSwNP is still unclear METHODS: We investigated expression profiles of messenger RNA (mRNA), microRNAs (miRNAs), and long noncoding RNAs (lncRNAs) in eosinophilic CRSwNP and constructed a global triple ceRNA network.

RESULTS

As a result, 964 differentially expressed mRNAs (DEmRs), 207 differentially expressed miRNAs (DEmiRs), and 15 differentially expressed lncRNAs (DElncRs) were identified, and a ceRNA network containing 598 miRNA-mRNA pairs and 70 lncRNA-miRNA pairs was finally constructed. Gene set enrichment analysis (GSEA) results indicated these DEmRs were mainly enriched in "cytokine-cytokine receptor interaction," "salivary secretion," "hematopoietic cell lineage," and "chemokine signaling pathway." Moreover, we also predicted the subcellular localization of the DElncRs identified in the network via bioinformatics approaches  CONCLUSION: In summary, the present study provided the first comprehensive assessment of the ceRNA crosstalk in eosinophilic CRSwNP. These findings will be of interest to the understanding of the potential pathophysiology of this disease.

Identification of a circRNA/miRNA/mRNA ceRNA Network as a Cell Cycle-Related Regulator for Chronic Sinusitis with Nasal Polyps

Purpose

To explore the mechanisms by which circRNA/miRNA/mRNA competitive endogenous RNAs (ceRNA) networks regulate CRSwNP.

Methods

The expression profiles of circRNAs, miRNAs, and mRNAs from patients with CRSwNP and control subjects were acquired from the Gene Expression Omnibus database. The circRNA/miRNA/mRNA ceRNA network was constructed based on the predicted circRNA–miRNA interactions and miRNA–mRNA interactions. Hub-mRNAs were screened by protein–protein interaction network analysis and Cytoscape molecular complex detection. The expression of factors in tissue and in hsa_circ_0031594 siRNA transfection cells was verified by RT-qPCR and the association between them was revealed by Spearman correlation analysis. Receiver operating characteristic curve analysis was performed with the pROC R package.

Results

The differential expression of 5423 circRNAs, 415 miRNAs, and 3673 mRNAs was identified in CRSwNP subjects compared to control subjects. Among these, 9 circRNAs, 39 miRNAs, and 78 mRNAs were screened to construct a ceRNA network. Ultimately, a subnetwork including circRNA hsa_circ_0031594, hsa-miR-1260b, hsa-miR-6507-5p, NCAPG2, RACGAP1, CHEK1 and PRC1 was screened out. RT-qPCR validated that the expression of hsa_circ_0031594, NCAPG2, PRC1 was significantly increased, and hsa-miR-1260b and hsa-miR-6507-5p were expressed significantly less in patients with CRSwNP than in control subjects. In addition, the AUCs of hsa_circ_0031594, hsa-miR-1260b, hsa-miR-6507-5p, NCAPG2, and PRC1 to discriminate CRSwNP patients were 0.995, 0.842, 0.862, 0.765, and 0.816. Spearman correlation showed that the expression of hsa_circ_0031594 was negatively correlated with hsa-miR-1260b and hsa-miR-6507-5p, and positively correlated with NCAPG2 and PRC1. In human nasal epithelial cell (HNEpC) line, knocking down hsa_circ_0031594 could increase the expression of hsa-miR-1260b and hsa-miR-6507-5p, and reduce the expression of NCAPG2 and PRC1.

Conclusion

CeRNA networks including hsa_circ_0031594, hsa-miR-1260b, and NCAPG2, and hsa_circ_0031594, hsa-miR-6507-5p, and PRC1 may be key regulators for CRSwNP occurrence, and may be potential targets for the pathogenesis and treatment development of CRSwNP.

Transcription Factor Specificity Protein 1 Regulates Inflammation and Fibrin Deposition in Nasal Polyps Via the Regulation of microRNA-125b and the Wnt/β-catenin Signaling Pathway

Nasal polyps (NPs) are multifactorial soft growths inside the nasal passages and are associated with chronic inflammation that originate from the nasal and paranasal sinus mucosae. This study focused on the role of microRNA (miR)-125b and the molecules associated with NP development. Differentially expressed miRNAs between nasal tissues from patients with chronic rhinosinusitis (CRS) with NP (CRSwNP) and CRS without NP (CRSsNP) were screened using microarray analysis. A murine model of CRSwNP was established. The expression of miR-125b in murine tissues was examined using reverse transcription quantitative polymerase chain reaction. Candidate upstream regulators of miR-125b were predicted using bioinformatics tools, and the binding relationship between specificity protein 1 (Sp1) and miR-125b was validated using luciferase and chromatin immunoprecipitation assays. Altered expression of Sp1 and miR-125b was induced to evaluate their relevance to the progression of NPs. miR-125b expression was significantly upregulated in NP tissues from patients with CRSwNP. Sp1 was confirmed as an upstream regulator that promotes miR-125b transcription in NPs. Overexpression of Sp1 reduced levels of d-dimer (an indicator of fibrinogen degradation products) and tissue-type plasminogen activator (t-PA) but increased eosinophil cationic protein and peroxidase levels, as well as the levels of inflammatory factors interleukin-5 (IL-5) and IL-8 in murine NP tissues. However, these trends were reversed after miR-125b downregulation. Sp1 and miR-125b were found to activate the Wnt/β-catenin signaling pathway in NPs. This study demonstrated that Sp1, an upstream transcription factor of miR-125b, accumulates on the miR-125b promoter to activate its transcription, which induces inflammation and fibrin deposition in NP by activating the Wnt/β-catenin axis.

Barrier Impairment and Type 2 Inflammation in Allergic Diseases: The Pediatric Perspective

Allergic diseases represent a global burden. Although the patho-physiological mechanisms are still poorly understood, epithelial barrier dysfunction and Th2 inflammatory response play a pivotal role. Barrier dysfunction, characterized by a loss of differentiation, reduced junctional integrity, and altered innate defence, underpins the pathogenesis of allergic diseases. Epithelial barrier impairment may be a potential therapeutic target for new treatment strategies Up now, monoclonal antibodies and new molecules targeting specific pathways of the immune response have been developed, and others are under investigation, both for adult and paediatric populations, which are affected by atopic dermatitis (AD), asthma, allergic rhinitis (AR), chronic rhinosinusitis with nasal polyps (CRSwNP), or eosinophilic esophagitis (EoE). In children affected by severe asthma biologics targeting IgE, IL-5 and against IL-4 and IL-13 receptors are already available, and they have also been applied in CRSwNP. In severe AD Dupilumab, a biologic which inhibits both IL-4 and IL-13, the most important cytokines involved in inflammation response, has been approved for treatment of patients over 12 years. While a biological approach has already shown great efficacy on the treatment of severe atopic conditions, early intervention to restore epithelial barrier integrity, and function may prevent the inflammatory response and the development of the atopic march.

Inflammatory Endotypes and Tissue Remodeling Features in Antrochoanal Polyps

Purpose

The pathogenic mechanisms of antrochoanal polyps (ACPs) remain largely unknown. This study aimed to characterize inflammatory patterns and tissue remodeling features in ACPs.

Methods

Inflammatory cell infiltration and tissue edema severity as well as fibrin deposition in ACPs and bilateral eosinophilic and noneosinophilic nasal polyps (NPs) were studied with immunohistochemical and immunofluorescence staining. Cytokine levels in sinonasal tissues were detected with the Bio-Plex assay. The expression of coagulation and fibrinolytic markers was measured using reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assays.

Results

Compared to control tissues and bilateral eosinophilic and noneosinophilic NPs, ACPs had higher levels of neutrophil infiltration and expression of myeloperoxidase (MPO), interleukin (IL)-8 and interferon (IFN)-γ. In total, 94.4% of ACPs demonstrated an eosinophil cationic protein/MPO ratio of < 1, compared to 79.0% of noneosinophilic and 26% of eosinophilic NPs. Principle component and multiple correspondence analyses revealed a neutrophilic and type 1 inflammation pattern in ACPs. Compared to control tissues, edema scores and fibrin deposition were increased, whereas d-dimer and tissue plasminogen activator (tPA) levels were decreased in ACPs and bilateral NPs, with more prominent changes in ACPs even than in eosinophilic NPs. The tPA levels were negatively correlated with IFN-γ, IL-8, and MPO levels in ACPs. Neutrophils were the major cellular source of IFN-γ in ACPs, and the number of IFN-γ⁺ neutrophils was elevated in ACPs than in control tissues and bilateral eosinophilic and noneosinophilic NPs.

Conclusions

ACPs are characterized by the neutrophilic and type 1 inflammation endotype. Neutrophil-derived IFN-γ is associated with reduced tPA production in ACPs.

Regulation of airway immunity by epithelial miRNAs

The airway epithelium is essential to protect the host from inhaled pathogens and particles. It maintains immune homeostasis and mediates tissue repair after injury. Inflammatory diseases of the airways are associated with failure of epithelial functions, including loss of barrier integrity that results in increased tissue permeability and immune activation; excessive mucus secretion and impaired mucociliary clearance that leads to airflow obstruction and microbial overgrowth; and dysregulation of cellular signals that promotes inflammation and alters tissue structure and airway reactivity. MicroRNAs play crucial roles in mounting appropriate cellular responses to environmental stimuli and preventing disease, using a common machinery and mechanism to regulate gene expression in epithelial cells, immune cells of hematopoietic origin, and other cellular components of the airways. Respiratory diseases are accompanied by dramatic changes in epithelial miRNA expression that drive persistent immune dysregulation. In this review, we discuss responses of the epithelium that promote airway immunopathology, with a focus on miRNAs that contribute to the breakdown of essential epithelial functions. We emphasize the emerging role of miRNAs in regulation of epithelial responses in respiratory health and their value as diagnostic and therapeutic targets.

Role of microRNAs in inflammatory upper airway diseases

MicroRNAs (miRNAs) are a conserved family of small endogenous noncoding RNA molecules that modulate post-transcriptional gene expression in physiological and pathological processes. miRNAs can silence target mRNAs through degradation or inhibition of translation, showing their pivotal role in the pathogenesis of many human diseases. miRNAs play a role in regulating immune functions and inflammation and are implicated in controlling the development and activation of T and B cells. Inflammatory chronic upper airway diseases, such as rhinitis and rhinosinusitis, are spread all over the world and characterized by an exaggerated inflammation involving a complex interaction between immune and resident cells. Until now and despite allergy, little is known about their etiology and the processes implicated in the immune response and tuning inflammation of these diseases. This review highlights the knowledge of the current literature about miRNAs in inflammatory chronic upper airways diseases and how this may be exploited in the development of new clinical and therapeutic strategies.

Can altered colostrum miRNA expression profile after cesarean delivery be a risk factor for autoimmune diseases?

PROBLEM

The cesarean section (CS) rate has increased significantly in North America, Western Europe, and Latin America. However, it has been reported that the incidence of inflammatory and autoimmune diseases such as asthma and type 1 diabetes increased in parallel with CS in these countries. Our aim was to investigate the expression level of miRNAs associated with inflammatory response and autoimmune diseases in colostrum samples and contribute to elucidating the role of CS in the pathogenesis of immune system-related diseases.

METHOD OF STUDY

Colostrum samples were taken from voluntary mothers who had 40 normal and 50 cesarean births. miRNAs were extracted from colostrums and detected to miRNA expression profiling (eighty-four miRNAs) by quantitative real-time PCR with the Fluidigm integrated microfluidic circuit technology.

RESULTS

There was a statistically significant change in the expression levels of 17 miRNAs in the colostrums of mothers who had normal and cesarean delivery (p < .05), and all of miRNAs were upregulated in the colostrums of mothers who have had cesarean delivery.

CONCLUSION

Our best knowledge is that the study we conducted was the first to investigate the effect of delivery method (CS or normal) on the miRNA profile of colostrum. Cesarean delivery is a potential risk factor for inflammatory and immune system-related diseases in children due to dysregulation in miRNA expression.

Spotlight on microRNAs in allergy and asthma

In past 10 years, microRNAs (miRNAs) have gained scientific attention due to their importance in the pathophysiology of allergic diseases and their potential as biomarkers in liquid biopsies. They act as master post‐transcriptional regulators that control most cellular processes. As one miRNA can target several mRNAs, often within the same pathway, dysregulated expression of miRNAs may alter particular cellular responses and contribute, or lead, to the development of various diseases. In this review, we give an overview of the current research on miRNAs in allergic diseases, including atopic dermatitis, allergic rhinitis, and asthma. Specifically, we discuss how individual miRNAs function in the regulation of immune responses in epithelial cells and specialized immune cells in response to different environmental factors and respiratory viruses. In addition, we review insights obtained from experiments with murine models of allergic airway and skin inflammation and offer an overview of studies focusing on miRNA discovery using profiling techniques and bioinformatic modeling of the network effect of multiple miRNAs. In conclusion, we highlight the importance of research into miRNA function in allergy and asthma to improve our knowledge of the molecular mechanisms involved in the pathogenesis of this heterogeneous group of diseases.

Gene Expression Profiles of Circular RNAs and MicroRNAs in Chronic Rhinosinusitis With Nasal Polyps

Introduction: Chronic rhinosinusitis (CRS) is often classified primarily on the basis of the absence or presence of nasal polyps (NPs), that is, as CRS with nasal polyps (CRSwNP) or CRS without nasal polyps (CRSsNP). Additionally, according to the percentage of eosinophils, CRSwNP can be further divided into eosinophilic CRSwNP (ECRSwNP) and non-ECRSwNP. CRSwNP is a significant public health problem with a considerable socioeconomic burden. Previous research reported that the pathophysiology of CRSwNP is a complex, multifactorial disease. There have been many studies on its etiology, but its pathogenesis remains unclear. Dysregulated expression of microRNAs (miRNAs) has been shown in psoriasis, rheumatoid arthritis, pulmonary fibrosis, and allergic asthma. Circular RNAs (circRNAs) are also involved in inflammatory diseases such as rheumatoid arthritis, septic acute kidney injury, myocardial ischemia/reperfusion injury, and sepsis-induced liver damage. The function of miRNAs in various diseases, including CRSwNP, is a research hotspot. In contrast, there have been no studies on circRNAs in CRSwNP. Overall, little is known about the functions of circRNAs and miRNAs in CRSwNP. This study aimed to investigate the expression of circRNAs and miRNAs in a CRSwNP group and a control group to determine whether these molecules are related to the occurrence and development of CRSwNP.

Methods: Nine nasal mucosa samples were collected, namely, three ECRSwNP samples, three non-ECRSwNP samples, and three control samples, for genomic microarray analysis of circRNA and microRNA expression. All of the tissue samples were from patients who were undergoing functional endoscopic sinus surgery in our department. Then we selected some differentially expressed miRNAs and circRNAs for qPCR verification. Meanwhile, GO enrichment analysis and KEGG pathway analysis were applied to predict the biological functions of aberrantly expressed circRNAs and miRNAs based on the GO and KEGG databases. Receiver operating characteristic (ROC) curve analysis and principal component analysis (PCA) were performed to confirm these molecules are involved in the occurrence and development of CRSwNP.

Results: In total, 2,875 circRNAs showed significant differential expression in the CRSwNP group. Specifically, 1794 circRNAs were downregulated and 1,081 circRNAs were upregulated. In the CRSwNP group, the expression of 192 miRNAs was significantly downregulated, and none of the miRNAs were significantly upregulated. GO and KEGG analysis showed differential circRNAs and miRNAs were enriched in “amoebiasis,” “salivary secretion,” “pathways in cancer,” and “endocytosis.” Through qRT-PCR verification, the expression profiles of hsa-circ-0031593, hsa-circ-0031594, hsa-miR-132-3p, hsa-miR-145-5p, hsa-miR-146a-5p, and hsa-miR-27b-3p were shown to have statistical differences. In addition, ROC curve analysis showed that the molecules with the two highest AUCs were hsa-circ-0031593 with AUC 0.8353 and hsa-miR-145-5p with AUC 0.8690. Through PCA with the six ncRNAs, the first principal component explained variance ratio was 98.87%. The AUC of the six ncRNAs was 0.8657.

Conclusion: In our study, the expression profiles of ECRSwNP and non-ECRSwNP had no statistical differences. The differentially expressed circRNAs and miRNAs between CRSwNP and control may play important roles in the pathogenesis of CRSwNP. Altered expression of hsa-circ-0031593 and hsa-miR-145-5p have the strongest evidence for involvement in the occurrence and development of CRSwNP because their AUCs are higher than the other molecules tested in this study.

MiR-21-5p in Macrophage-Derived Exosomes Targets Smad7 to Promote Epithelial Mesenchymal Transition of Airway Epithelial Cells

Background

Asthma is usually associated with airway inflammation and airway remodeling. Epithelial mesenchymal transition (EMT) often occurs in airway remodeling. The purpose of this study is to identify the effect of miR-21-5p and Smad7 signaling pathway in macrophage-derived exosomes on EMT of airway epithelial cells.

Methods

HE staining and Masson staining were used to verify the successful establishment of the asthma model. The levels of epithelial cell adhesion factor and stromal cell markers were detected by Western blot. The levels of miR-21-5p were detected by qRT-PCR. The expression of miR-21-5p in lung tissue was further verified by fluorescence in situ hybridization (FISH). Exosome morphology was observed by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Luciferase reporter assay was applied to analyze the interaction of miR-21-5p with Smad7.

Results

The expression of miR-21-5p was upregulated in macrophages of rats in vivo with OVA-induced asthma. In vitro cultured alveolar macrophages stimulated by LPS could secrete exosomes with high levels of miR-21-5p. The exosome-derived miR-21-5p promotes EMT in rat tracheal epithelial cells through TGFβ1/Smad signaling pathway by downregulating Smad7. This process can be blocked by miR-21-5p inhibitor.

Conclusion

Rat alveolar macrophages produced high levels of miR-21-5p-containing exosomes, which transported miR-21-5p to tracheal epithelial cells, thus promoting EMT through TGF-β1/Smad signaling pathway by targeting Smad7.

Metformin and insulin-resistant related diseases: Emphasis on the role of microRNAs

Metformin is one of the most prescribed drugs in type II diabetes (T2DM) which has recently found new applications in the prevention and treatment of various illnesses, from metabolic disorders to cardiovascular and age-related diseases. Metformin improves insulin resistance (IR) by modulating metabolic mechanisms and mitochondrial biogenesis. Alternation of microRNAs (miRs) in the treatment of IR-related illnesses has been observed by metformin therapy. MiRs are small non-coding RNAs that play important roles in RNA silencing, targeting the 3'untranslated region (3'UTR) of most mRNAs and inhibiting the translation of related proteins. As a result, their dysregulation is associated with many diseases. Metformin may alter miRs levels in the treatment of various diseases by AMPK-dependent or AMPK-independent mechanisms. Here, we summarized the therapeutic role of metformin by modifying the aberrant expression of miRs as potential biomarkers or therapeutic targets in diseases in which IR plays a key role.

Stromal cells and B cells orchestrate ectopic lymphoid tissue formation in nasal polyps

BACKGROUND

Although the importance of ectopic lymphoid tissues (eLTs) in the pathophysiology of nasal polyps (NPs) is increasingly appreciated, the mechanisms underlying their formation remain unclear.

OBJECTIVE

To study the role of interleukin (IL)-17A, C-X-C motif chemokine ligand 13 (CXCL13) and lymphotoxin (LT) in eLT formation in NPs.

METHODS

The expression levels of CXCL13 and LT and their receptors, in addition to the phenotypes of stromal cells in NPs, were studied by flow cytometry, immunostaining, and real-time reverse transcription-polymerase chain reaction (RT-PCR). Purified nasal stromal cells and B cells were cultured, and a murine model of nasal type 17 inflammation was established by intranasal curdlan challenge for the mechanistic study.

RESULTS

The excessive CXCL13 production in NPs correlated with enhanced IL-17A expression. Stromal cells, with CD31^- Pdpn⁺ fibroblastic reticular cell (FRC) expansion, were the major source of CXCL13 in NPs without eLTs. IL-17A induced FRC expansion and CXCL13 production in nasal stromal cells. In contrast, B cells were the main source of CXCL13 and LTα₁ β₂ in NPs with eLTs. CXCL13 upregulated LTα₁ β₂ expression on B cells, which in turn promoted CXCL13 production in nasal B cells and stromal cells. LTα₁ β₂ induced expansion of FRCs and CD31⁺ Pdpn⁺ lymphoid endothelial cells, which were the predominant stromal cell types in NPs with eLTs. IL-17A knockout and CXCL13 and LTβR blockage diminished nasal eLT formation in the murine model.

CONCLUSION

We identified an important role of IL-17A-induced stromal cell remodeling in the initiation and crosstalk between B and stromal cells via CXCL13 and LTα₁ β₂ in the enlargement of eLTs in NPs.

Defective STING expression potentiates IL-13 signaling in epithelial cells in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Stimulator of interferon genes (STING) activation favors effective innate immune responses against viral infections. Its role in chronic rhinosinusitis with nasal polyps (CRSwNP) remains unknown.

OBJECTIVE

Our aim was to explore the expression, regulation, and function of STING in CRSwNP.

METHODS

STING expression in sinonasal mucosal samples was analyzed by means of quantitative RT-PCR, immunohistochemistry, flow cytometry, and Western blotting. Regulation and function of STING expression were explored by using cultured primary human nasal epithelial cells (HNECs) and cells of the line BEAS-2B in vitro.

RESULTS

STING expression was reduced in eosinophilic nasal polyps compared with that in noneosinophilic nasal polyps and control tissues. STING was predominantly expressed by epithelial cells in nasal tissue and was downregulated by IL-4 and IL-13 in a signal transducer and activator of transcription 6 (STAT6)-dependent manner. HNECs derived from eosinophilic polyps displayed compromised STING-dependent type I interferon production but heightened IL-13-induced STAT6 activation and CCL26 production as compared with HNECs from noneosinophilic polyps and control tissues, which were rescued by exogenous STING overexpression. Knocking down or overexpressing STING decreased or enhanced expression of suppressor of cytokine signaling 1 (SOCS1) in BEAS-2B cells, respectively, independent of the canonic STING pathway elements TBK1 and IRF3. Knocking down SOCS1 abolished the inhibitory effect of STING on IL-13 signaling in BEAS-2B cells. STING expression was positively correlated with SOCS1 expression but negatively correlated with CCL26 expression in nasal epithelial cells from patients with CRSwNP.

CONCLUSIONS

Reduced STING expression caused by the type 2 milieu not only impairs STING-dependent type I interferon production but also amplifies IL-13 signaling by decreasing SOCS1 expression in nasal epithelial cells in eosinophilic CRSwNP.

MicroRNA Expression in Extracellular Vesicles from Nasal Lavage Fluid in Chronic Rhinosinusitis

Extracellular vesicles (EVs) are nanovesicles of endocytic origin released by cells and found in human bodily fluids. EVs contain both mRNA and microRNA (miRNA), which can be shuttled between cells, indicating their role in cell communication. This study investigated whether nasal secretions contain EVs and whether these EVs contain RNA. EVs were isolated from nasal lavage fluid (NLF) using sequential centrifugation. EVs were characterized and EV sizes were identified by transmission electron microscopy (TEM). In addition, EV miRNA expression was different in the chronic rhinosinusitis without nasal polyp (CRSsNP) and chronic rhinosinusitis with nasal polyp (CRSwNP) groups. The Kyoto encyclopedia gene and genome database (KEGG) database was used to identify pathways associated with changed miRNAs in each analysis group. Twelve miRNAs were differentially expressed in NLF-EVs of CRS patients versus HCs. In addition, eight miRNAs were differentially expressed in NLF-EVs of CRSwNP versus CRSsNP patients. The mucin-type O-glycan biosynthesis was a high-ranked predicted pathway in CRS patients versus healthy controls (HCs), and the Transforming growth factor beta (TGF-β) signaling pathway was a high-ranked predicted pathway in CRSwNP versus CRSsNP patients. We demonstrated the presence of and differences in NLF-EV miRNAs between CRS patients and HCs. These findings open up a broad and novel area of research on CRS pathophysiology as driven by miRNA cell communication.

Elevated microRNA-21 Is a Brake of Inflammation Involved in the Development of Nasal Polyps

Background

CRSwNP is an inflammatory disease but the mechanism is not yet fully understood. MiR-21, a member of miRNAs, has been reported to play roles in mediating inflammation. However, the expression of miR-21 and its role in patients with CRSwNP remain elusive.

Methods

Turbinates from control subjects, uncinate processes from CRSsNP, polyp tissues from CRSwNP, and nasal epithelial cells brushed from nasal mucosa were collected. The expression of miR-21 and cytokines in nasal tissues and epithelial cells were detected by qPCR. The localization of miR-21 was detected by ISH, and its target was identified by bioinformation analysis, qPCR, IHC, WB, and luciferase reporter system. The protein and mRNA of PDCD4 and NF-κB P65 were determined by WB and qPCR after miR-21 transfection in HNEpC. The role of miR-21 on cytokines was analyzed in HNEpC and nasal polyp explants.

Results

MiR-21 was upregulated in CRSwNP relative to control subjects by qPCR, which was determined mainly in nasal epithelial cells of CRSwNP by ISH. Both pro-inflammation cytokines (IL-1β, IL-6, IL-8, IL-25, and TSLP) and a suppressive cytokine (IL-10) were overexpressed in the epithelial cells of CRSwNP. The expression of miR-21 was positively correlated with IL-10 and negatively correlated with IL-6, IL-8, IL-33, and TSLP in the epithelial cells of CRSwNP. As a potential target of miR-21, the expression of PDCD4 was negatively correlated with miR-21 in CRSwNP. In HNEpC, miR-21 could reduce the expression of PDCD4 at both mRNA and protein levels, and bioinformation analysis and luciferase reporter system confirmed PDCD4 as one target of miR-21. Furthermore, miR-21 could decrease the activation of NF-κB and increase IL-10 mRNA. Both SEB and LPS could elevate miR-21, with IL-25, IL-33, TSLP induced by SEB and IL-1β, IL-6, IL-8 induced by LPS, while the miR-21 could regulate the expression of IL-33, TSLP, IL-1β, IL- 6 and IL-8 in vitro and ex vivo. Clinically, miR-21 expression was inversely correlated with the Lund-Mackay CT scores and the Lund-Kennedy scores in CRSwNP.

Conclusion

MiR-21 could be a prominent negative feedback factor in the inflammation process to attenuate the expression of pro-inflammatory cytokines, thereby playing an anti-inflammation role in CRSwNP.

Let-7a-5p regulates the inflammatory response in chronic rhinosinusitis with nasal polyps

BACKGROUND

Let-7a-5p is demonstrated to be a tumor inhibitor in nasopharyngeal carcinoma. However, the role of let-7a-5p in chronic rhinosinusitis with nasal polyps (CRSwNP) has not been reported. This study is designed to determine the pattern of expression and role of let-7a-5p in CRSwNP.

METHODS

The expression level of let-7a-5p, TNF-α, IL-1β, and IL-6 in CRSwNP tissues and cells were detected by RT-qPCR. Western blot assay was carried out to measure the protein expression of the Ras-MAPK pathway. Dual luciferase reporter assay and RNA pull-down assay were used to explore the relationship between let-7a-5p and IL-6.

RESULTS

Let-7a-5p was significantly downregulated in CRSwNP tissues and cells. Moreover, the mRNA expression of TNF-α, IL-1β and IL-6 was increased in CRSwNP tissues, while let-7a-5p mimic inhibited the expression of TNF-α, IL-1β and IL-6. Besides that, let-7a-5p was negatively correlated with TNF-α, IL-1β and IL-6 in CRSwNP tissues. In our study, IL-6 was found to be a target gene of let-7a-5p. Additionally, let-7-5p mimic obviously reduced the protein levels of Ras, p-Raf1, p-MEK1 and p-ERK1/2, while IL-6 overexpression destroyed the inhibitory effect of let-7a-5p on the Ras-MAPK pathway in CRSwNP.

CONCLUSION

We demonstrated that let-7a-5p/IL-6 interaction regulated the inflammatory response through the Ras-MAPK pathway in CRSwNP.

Integrated miRNA and mRNA expression profiling reveals dysregulated miRNA-mRNA regulatory networks in eosinophilic and non-eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

The precise mechanisms underlying pathogenesis of different subtypes of chronic rhinosinusitis with nasal polyps (CRSwNP) are still unclear. Emerging evidence indicates that microRNAs may play a role in the pathogenesis of CRSwNP. This study aimed to identify the dysregulated microRNA-messenger RNA (miRNA-mRNA) regulatory networks in eosinophilic (E) and non-eosinophilic (non-E) CRSwNP.

METHODS

Whole-transcriptome sequencing was performed on nasal tissues of patients with ECRSwNP and non-ECRSwNP, and control subjects. An integrated analysis of miRNA and mRNA expression was conducted to identify key mRNAs and miRNAs involved in the pathogenesis of ECRSwNP and non-ECRSwNP. The miRNAs of interest and their target genes were validated using quantitative real-time polymerase chain reaction (PCR).

RESULTS

A group of differentially expressed mRNAs (DE-mRNAs) and miRNAs (DE-miRs) were identified in ECRSwNP patients vs control subjects, non-ECRSwNP patients vs control subjects, and non-ECRSwNP vs ECRSwNP patients, respectively. Pathway enrichment analysis showed distinct immune and inflammatory functions associated with DE-mRNAs and target genes of DE-miRs in ECRSwNP vs control and non-ECRSwNP vs control groups. The miRNA-mRNA regulatory networks constructed with Cytoscape highlighted the roles of miR-154, miR-221, and miR-223 family miRNAs relating to both ECRSwNP and non-ECRSwNP, and the roles of the let-7 and miR-34/449 families in the development of non-ECRSwNP. Assessment using real-time PCR for the expression of miRNAs and target genes demonstrated highly consistent data with the RNA sequencing data.

CONCLUSION

ECRSwNP and non-ECRSwNP patients express distinct miRNA-mRNA regulatory networks compared with control subjects, thus providing potential targets for future development of novel therapeutic approaches for the management of CRSwNP.

Cold-inducible RNA-binding protein contributes to tissue remodeling in chronic rhinosinusitis with nasal polyps

BACKGROUND

Cold-inducible RNA-binding protein (CIRP) is a newly identified damage-associated molecular pattern molecule. Its roles beyond promoting inflammation and in human diseases are poorly understood. This study aimed to investigate the involvement of CIRP in chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

Immunohistochemistry, quantitative RT-PCR, and ELISA were used to detect the expression of CIRP and matrix metalloproteinases (MMPs) in sinonasal mucosal samples and nasal secretions. Human nasal epithelial cells (HNECs) and THP-1 cells, a human monocytic/macrophage cell line, were cultured to explore the regulation of CIRP expression and MMP expression.

RESULTS

Cytoplasmic CIRP expression in nasal epithelial cells and CD68⁺ macrophages in sinonasal tissues, and CIRP levels in nasal secretions were significantly increased in both patients with eosinophilic and noneosinophilic CRSwNP as compared to those in control subjects. IL-4, IL-13, IL-10, IL-17A, TNF-α, Dermatophagoides pteronyssinus group 1, and lipopolysaccharide induced the production and secretion of CIRP from HNECs and macrophages differentiated from THP-1 cells. CIRP promoted MMP2, MMP7, MMP9, MMP12, and vascular endothelial growth factor A (VEGF-A) production from HNECs, macrophages differentiated from THP-1 cells, and polyp tissues, which was inhibited by the blocking antibody for Toll-like receptor 4, but not advanced glycation end products. The expression of MMPs and VEGF-A in tissues correlated with CIRP levels in nasal secretions in patients with CRSwNP.

CONCLUSIONS

The upregulated production and release of CIRP from nasal epithelial cells and macrophages may contribute to the edema formation in both eosinophilic and noneosinophilic CRSwNP by inducing MMP and VEGF-A production from epithelial cells and macrophages.

The Role of Epigenetics in the Chronic Sinusitis with Nasal Polyp

PURPOSE OF REVIEW

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and heterogeneous inflammatory disease. The underlying epigenetic mechanisms and treatment of CRSwNP are partially understood. Of the different epigenetic changes in CRSwNP, histone deacetylases (HDACs), methylation of DNA, and the levels of miRNA are widely studied. Here, we review the human studies of epigenetic mechanisms in CRSwNP.

RECENT FINDINGS

The promoters of COL18A1, PTGES, PLAT, and TSLP genes are hypermethylated in CRSwNP compared with those of controls, while the promoters of PGDS, ALOX5AP, LTB4R, IL-8, and FZD5 genes are hypomethylated in CRSwNP. Promoter hypermethylation suppresses the gene expression, while promoter hypomethylation increases the gene expression. Studies have shown the elevation in the levels of HDAC2, HDAC4, and H3K4me3 in CRSwNP. In CRSwNP patients, there is also an upregulation of certain miRNAs including miR-125b, miR-155, miR-19a, miR-142-3p, and miR-21 and downregulation of miR-4492. Epigenetics takes part in the immunology of CRSwNP and may give rise to endotypes of CRSwNP. Both HDAC2 and the miRNA including miR-18a, miR-124a, and miR-142-3p may take function in the regulation of glucocorticoid resistance. HDAC inhibitors and KDM2B have shown effectiveness in decreasing nasal polyp, and DNA methyltransferase (DNMT) or HDAC inhibitors may have a potential efficacy for the treatment of CRSwNP. Recent advances in the epigenetics of CRSwNP have led to the identification of several potential therapeutic targets for this disease. The use of epigenetics may provide novel and effective biomarkers and therapies for the treatment of nasal polyp.

miR-31 attenuates murine allergic rhinitis by suppressing interleukin-13-induced nasal epithelial inflammatory responses

The present study aimed to investigate whether microRNA (miR)-31 exerted therapeutic potential in allergic rhinitis (AR) and to explore its underlying mechanism. Firstly, the expression levels of miR-31 were detected by reverse transcription-quantitative PCR in the nasal mucosa of patients and mice. Subsequently, an ovalbumin (OVA)-induced animal model of AR was constructed. Allergic symptom score, histopathological characteristics, OVA-specific immunoglobulin E (IgE) titers, and T-helper (Th)1 and Th2 cell-related cytokine levels were analyzed in OVA-sensitized mice, miR-31-overexpressing mice, miR-negative control mice and control mice. Furthermore, interleukin (IL)-13-stimulated nasal epithelial cells (NECs) were used to assess the effects of miR-31 on the production of IL-13-induced inflammatory cytokines and mucin 5AC by performing western blotting and ELISA. The expression levels of miR-31 were significantly decreased in the nasal mucosa of the AR group compared with those in the control group. Moreover, upregulation of miR-31 markedly attenuated sneezing and nasal rubbing events, reduced nasal eosinophil infiltration and goblet cell hyperplasia, and decreased the levels of OVA-specific IgE and Th2-related cytokines. In addition, subsequent in vitro experiments showed that upregulation of miR-31 inhibited IL-13 receptor α1 chain expression and signal transducer and activator of transcription 6 phosphorylation in NECs. Furthermore, miR-31 suppressed IL-13-induced expression of thymic stromal lymphopoietin, granulocyte-macrophage colony-stimulating factor, eotaxin and mucin 5AC in NECs. In conclusion, these data revealed that miR-31 could ameliorate AR by suppressing IL-13-induced nasal epithelial inflammatory responses, and thus may serve as a novel therapeutic target for AR.

Effects of miR-101-3p on goat granulosa cells in vitro and ovarian development in vivo via STC1

Background

MiRNAs act as pivotal post-transcriptional gene mediators in the regulation of diverse biological processes, including proliferation, development and apoptosis. Our previous study has showed that miR-101-3p is differentially expressed in dairy goat ovaries compared single with multiple litters. The objective of this research was to explore the potential function and molecular mechanism of miR-101-3p via its target STC1 in goat ovarian growth and development.

Results

cDNA libraries were constructed using goat granulosa cells transfected with miR-101-3p mimics and negative control by RNA-sequencing. In total, 142 differentially expressed unigenes (DEGs) were detected between two libraries, including 78 down-regulated and 64 up-regulated genes. GO and KEGG enrichment analysis showed the potential impacts of DEGs on ovarian development. STC1 was singled out from DEGs for further research owing to it regulates reproductive-related processes. In vitro, bioinformatics analysis and 3′-UTR assays confirmed that STC1 was a target of miR-101-3p. ELISA was performed to detect the estrogen (E2) and progesterone (P4) levels. CCK8, EdU and flow cytometry assays were performed to detect the proliferation and apoptosis of granulosa cells. Results showed that miR-101-3p regulated STAR, CYP19A1, CYP11A1 and 3β-HSD steroid hormone synthesis-associated genes by STC1 depletion, thus promoted E2 and P4 secretions. MiR-101-3p also affected the key protein PI3K, PTEN, AKT and mTOR in PI3K-AKT pathway by STC1, thereby suppressing proliferation and promoting apoptosis of granulosa cells. In vivo, the distribution and expression levels of miR-101-3p in mouse ovaries were determined through fluorescence in situ hybridisation (FISH). Immunohistochemistry results showed that STC1 expression was suppressed in mouse ovaries in miR-101-3p-agonist and siRNA-STC1 groups. Small and stunted ovarian fragments, decreased numbers of follicles at diverse stages were observed using Hematoxylin-eosin (HE) staining, thereby showing unusual ovarian development after miR-101-3p overexpression or STC1 depletion. Inhibition of miR-101-3p manifested opposite results.

Conclusions

Taken together, our results demonstrated a regulatory mechanism of miR-101-3p via STC1 in goat granulosa cells, and offered the first in vivo example of miR-101-3p and STC1 functions required for ovarian development.

Up-regulation of microRNA-335-5p reduces inflammation via negative regulation of the TPX2-mediated AKT/GSK3β signaling pathway in a chronic rhinosinusitis mouse model

Chronic rhinosinusitis (CRS) is featured with chronic symptoms of inflammation or infection in the nasal and sinus tissues. MicroRNAs (miRNAs/miRs), such as dysregulated expression of miR-125b and miR-26a, has been previously demonstrated to be related to CRS. The present study is intended to define the role of miR-335-5p in inflammation and the related mechanism in a mouse model of CRS. The differentially expressed genes associated with CRS were screened by microarray analysis. The targeting relationship between miR-335-5p and TPX2 was analyzed by target prediction program and dual luciferase reporter gene assay. The mouse model of CRS was established, and mice were introduced with miR-335-5p mimics, miR-335-5p inhibitors, or siRNA against TPX2 to explore the regulatory functions of miR-335-5p. The regulatory effect of miR-335-5p on inflammation with the involvement of the AKT signaling pathway was also analyzed with the expression of inflammatory cytokines and AKT signaling pathway-related factors measured. It was indicated that miR-335-5p regulated the TPX2 gene-mediated AKT signaling pathway. TPX2 was identified as a target gene of miR-335-5p, and miR-335-5p elevation inhibited the activation of the AKT signaling pathway. In mice with CRS, up-regulation of miR-335-5p or silence of TPX2 inhibited the inflammation, as evidenced by decreased levels of TNF-α, IL-6 and IL-8, and higher levels of GSK3β and IL-10. Collectively, miR-335-5p inhibits the activation of AKT signaling pathway by negatively mediating TPX2, which may confer anti-inflammatory protection in CRS.

Chinese Society of Allergy and Chinese Society of Otorhinolaryngology-Head and Neck Surgery Guideline for Chronic Rhinosinusitis

The current document is based on a consensus reached by a panel of experts from the Chinese Society of Allergy and the Chinese Society of Otorhinolaryngology-Head and Neck Surgery, Rhinology Group. Chronic rhinosinusitis (CRS) affects approximately 8% of Chinese adults. The inflammatory and remodeling mechanisms of CRS in the Chinese population differ from those observed in the populations of European descent. Recently, precision medicine has been used to treat inflammation by targeting key biomarkers that are involved in the process. However, there are no CRS guidelines or a consensus available from China that can be shared with the international academia. The guidelines presented in this paper cover the epidemiology, economic burden, genetics and epigenetics, mechanisms, phenotypes and endotypes, diagnosis and differential diagnosis, management, and the current status of CRS in China. These guidelines-with a focus on China-will improve the abilities of clinical and medical staff during the treatment of CRS. Additionally, they will help international agencies in improving the verification of CRS endotypes, mapping of eosinophilic shifts, the identification of suitable biomarkers for endotyping, and predicting responses to therapies. In conclusion, these guidelines will help select therapies, such as pharmacotherapy, surgical approaches and innovative biotherapeutics, which are tailored to each of the individual CRS endotypes.

The impact of microRNAs on alterations of gene regulatory networks in allergic diseases

Allergic diseases including asthma are worldwide on the rise and contribute significantly to health expenditures. Allergic diseases are prototypic diseases with a strong gene by environment interaction component and epigenetic mechanisms might mediate the effects of the environment on the disease phenotype. MicroRNAs, small non-coding RNAs (miRNAs), regulate gene expression post-transcriptionally. Functional single-stranded miRNAs are generated in multiple steps of enzymatic processing from their precursors and mature miRNAs are included into the RNA-induced silencing complex (RISC). They imperfectly base-pair with the 3'UTR region of targeted genes leading to translational repression or mRNA decay. The cellular context and microenvironment as well the isoform of the mRNA control the dynamics and complexity of the regulatory circuits induced by miRNAs that regulate cell fate decisions and function. MiR-21, miR-146a/b and miR-155 are among the best understood miRNAs of the immune system and implicated in different diseases including allergic diseases. MiRNAs are implicated in the induction of the allergy reinforcing the Th2 phenotype (miR-19a, miR-24, miR-27), while other miRNAs promote regulatory T cells associated with allergen tolerance or unresponsiveness. In the current chapter we describe in detail the biogenesis and regulatory function of miRNAs and summarize current knowledge on miRNAs in allergic diseases and allergy relevant cell fate decisions focusing mainly on immune cells. Furthermore, we evoke the principles of regulatory loops and feedback mechanisms involving miRNAs on examples with relevance for allergic diseases. Finally, we show the potential of miRNAs and exosomes containing miRNAs present in several biological fluids that can be exploited with non-invasive procedures for diagnostic and potentially therapeutic purposes.

Chloroquine Treatment Suppresses Mucosal Inflammation in a Mouse Model of Eosinophilic Chronic Rhinosinusitis

PURPOSE

The Toll-like receptor 9 (TLR9) signaling pathway is involved in the pathogenesis of chronic rhinosinusitis (CRS) with nasal polyposis. The aim of this study was to assess the therapeutic potential of the TLR9 pathway inhibitor chloroquine in CRS mice.

METHODS

The expression of type I interferons (IFNs) in human CRS tissues was evaluated using quantitative polymerase chain reaction (qPCR), western blotting, and immunofluorescence. Mice were divided into 4 treatment groups: the control, nasal polyp (NP), chloroquine treatment (NP + Chlq), and dexamethasone treatment (NP + Dexa) groups. The effects of chloroquine on polyp formation and mucosal inflammation were examined by hematoxylin and eosin staining. The expression levels of type I IFN, B-cell activating factor (BAFF), TLR9, high mobility group box 1 (HMGB1), and proinflammatory cytokine expression levels were assessed using qPCR, western blot, or enzyme-linked immunosorbent assay.

RESULTS

IFN-α and IFN-β mRNA levels were significantly higher in patients with eosinophilic NPs (EPs) than in healthy individuals or non-EP patients. The polyp score, epithelial thickness, mucosal thickness, and the number of eosinophils in nasal mucosa were significantly higher in the NP group compared with the control, NP + Chlq, and NP + Dexa groups. NP + Chlq or NP + Dexa significantly suppressed the induction of type I IFN and BAFF expression in the NP group; these treatments also significantly suppressed the induction of TLR9, HMGB1, interferon regulatory factors, interleukin (IL)-6, IL-1β, tumor necrosis factor-α, and Th cytokine expression in the NP group. The secreted levels of anti-dsDNA Immunoglobulin G (IgG) were significantly higher in the NP group than in the control, NP + Chlq, and NP + Dexa groups. There were significant positive correlations between BAFF and mRNA levels of IFN-α/β/the protein levels of anti-dsDNA IgG.

CONCLUSIONS

Chloroquine may be used for the treatment of patients with eosinophilic CRS.

Differential expression of miR-4492 and IL-10 is involved in chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis (CRS) is one of the most common types of respiratory disease and affects a large proportion of the population worldwide. The clinical differences between CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP) facilitate studies on the development of polyps. In the present study, next-generation sequencing was performed to identify differentially expressed microRNAs (miRNAs/miRs) in CRSwNP vs. CRSsNP tissues and subsequently validated the expression of selected genes using reverse transcription-quantitative polymerase chain reaction analysis. In total, 6 miRNAs were identified to be downregulated in the CRSwNP samples compared with those in the CRSsNP samples. The predicted targets of these miRNAs were determined to be enriched in a number of signaling pathways, including the ErbB, Ras, cyclic adenosine monophosphate and Janus kinase (Jak)/signal transducer and activator of transcription (STAT) pathways. The expression of miR-4492 and that if its targets predicted by a bioinformatics analysis, tumor necrosis factor α (TNF-α) and interleukin (IL)-10, was validated in 96 clinical specimens. miR-4492 was downregulated and IL-10 was upregulated in CRSwNP vs. CRSsNP tissues, and an inverse correlation between miR-4492 and IL-10 was determined in CRS tissues; however no difference was identified in the expression of TNF-α between the different groups. The present results indicate that the miR-4492/IL-10 interaction in the Jak/STAT signaling pathway may be one of the key mechanisms in CRSwNP.

MEK inhibition drives anti-viral defence in RV but not RSV challenged human airway epithelial cells through AKT/p70S6K/4E-BP1 signalling

BACKGROUND

The airway epithelium is a major target tissue in respiratory infections, and its antiviral response is mainly orchestrated by the interferon regulatory factor-3 (IRF3), which subsequently induces type I (β) and III (λ) interferon (IFN) signalling. Dual specificity mitogen-activated protein kinase kinase (MEK) pathway contributes to epithelial defence, but its role in the regulation of IFN response in human primary airway epithelial cells (AECs) is not fully understood. Here, we studied the impact of a small-molecule inhibitor (MEKi) on the IFN response following challenge with two major respiratory viruses rhinovirus (RV2) and respiratory syncytial virus (RSVA2) and a TLR3 agonist, poly(I:C).

METHODS

The impact of MEKi on viral load and IFN response was evaluated in primary AECs with or without a neutralising antibody against IFN-β. Quantification of viral load was determined by live virus assay and absolute quantification using qRT-PCR. Secretion of cytokines was determined by AlphaLISA/ELISA and expression of interferon-stimulated genes (ISGs) was examined by qRT-PCR and immunoblotting. A poly(I:C) model was also used to further understand the molecular mechanism by which MEK controls IFN response. AlphaLISA, siRNA-interference, immunoblotting, and confocal microscopy was used to investigate the effect of MEKi on IRF3 activation and signalling. The impact of MEKi on ERK and AKT signalling was evaluated by immunoblotting and AlphaLISA.

RESULTS

Here, we report that pharmacological inhibition of MEK pathway augments IRF3-driven type I and III IFN response in primary human AECs. MEKi induced activation of PI3K-AKT pathway, which was associated with phosphorylation/inactivation of the translational repressor 4E-BP1 and activation of the protein synthesis regulator p70 S6 kinase, two critical translational effectors. Elevated IFN-β response due to MEKi was also attributed to decreased STAT3 activation, which consequently dampened expression of the transcriptional repressor of IFNB1 gene, PRDI-BF1. Augmented IFN response translated into inhibition of rhinovirus 2 replication in primary AECs but not respiratory syncytial virus A2.

CONCLUSIONS

Our findings unveil MEK as a key molecular mechanism by which rhinovirus dampens the epithelial cell's antiviral response. Our study provides a better understanding of the role of signalling pathways in shaping the antiviral response and suggests the use of MEK inhibitors in anti-viral therapy against RV.