MicroRNA-21 expression in neonatal blood associated with antenatal immunoglobulin E production and development of allergic rhinitis

MiR-223-3p regulates the eosinophil degranulation and enhances the inflammation in allergic rhinitis by targeting FBXW7

OBJECTIVES

MiR-223-3p is a multifunctional microRNA regulated by multiple transcription factors and plays a critical role in inflammation. This paper was designed to investigate the regulatory role and mechanism of miR-223-3p in eosinophils degranulation and allergic rhinitis (AR) inflammation.

METHODS

OVA sensitized AR mouse model and EOL-1 cells model were established. RT-qPCR and FISH were performed to detect the miR-223-3p expression. ELISA and WB were utilized to evaluate mRNA and protein expression. HE staining and transmission electron microscopy were applied to observe the morphological changes in nasal mucosa. Flow cytometry and immunofluorescence staining were performed to measure the proportion of eosinophils and eosinophilic major basic protein expression. The targeting relationship between miR-223-3p and FBXW7 was verified by bioinformatic analysis and dual-luciferase reporter gene assay. The expression of FBXW7 was detected by immunohistochemistry.

RESULTS

The level of miR-223-3p in nasal mucosa was significantly up-regulated in AR group. The expression of miR-223-3p, ECP, MBP, and EPO were increased in EOL-1 cells, further increasing the miR-223-3p level could promote the ECP and EPO mRNA expression. Upregulation of miR-223-3p increased eosinophils granule protein expression, aggravated mucosal destruction and enhanced AR inflammation. Luciferase assay verified miR-223-3p directly target the 3'-UTR of FBXW7. In vitro, overexpression of FBXW7 could reverse the increase in MBP expression caused by the up-regulation of miR-223-3p. In vivo, knockdown of FBXW7 could reverse the down-regulation in granule protein level caused by the down-regulation of miR-223-3p, thereby aggravating AR inflammation.

CONCLUSION

Collected evidence elucidated that miR-223-3p could regulate the eosinophil degranulation and enhances the inflammation in AR by targeting FBXW7. The miR-223-3p/FBXW7 axis may provide a novel approach for AR treatment.

Innate and adaptive immunity in allergic airway disease

PURPOSE OF REVIEW

This article explores recent findings on the involvement of innate immunity in allergic airways disease, concentrating on allergic rhinitis.

RECENT FINDINGS

We speculate on the ways in which environmental influences act to initiate inflammation and on how these may have altered in recent decades. Improved understanding of the mechanisms involved may reveal future possibilities for therapy.

SUMMARY

The complex nature of immunity - both innate and acquired - in airways disease has implications for prevention and for therapy and requires further elucidation.

Quercetin attenuates lipopolysaccharide-mediated inflammatory injury in human nasal epithelial cells via regulating miR-21/DMBT1/NF-κB axis

BACKGROUND

Quercetin (Qu) belongs to a flavonoid polyphenolic compound present in fruits and vegetables which has been confirmed to exert anti-inflammatory properties. Our study aimed to explore the impacts of quercetin on lipopolysaccharide (LPS)-induced inflammatory injury and signal transduction of miR-21/DMBT1/NF-κB axis in human nasal epithelial cells (HNEpC).

METHODS

HNEpCs were cultured and treated with 1 μg/mL of LPS and a gradient concentration (10, 100, and 200 μM) of quercetin for 24 h. Cell viability, apoptosis, and cytokines were detected to assess the inflammatory injury in LPS-exposed HNEpCs. The expressions of miR-21, DMBT1, and NF-κB mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of DMBT1 and NF-κB protein were measured by western blotting.

RESULTS

LPS treatment reduced cell viability, promoted cell apoptosis and inflammatory response, down-regulated miR-21 expression and up-regulated DMBT1, and NF-κB in HNEpC cells. Quercetin exerted the opposite effects to attenuate LPS-induced inflammatory injury in HNEpC cells at a concentration-dependent way. Additionally, miR-21 directly targeted DMBT1 to reduce its expression and further inducing cell viability via inhibiting cell apoptosis and inflammatory response. MiR-21 inhibition or DMBT1 over-expression weakened the protective effects of quercetin against LPS-induced inflammatory injury in HNEpC cells.

CONCLUSIONS

Quercetin could protect HNEpC cells against LPS-induced inflammatory injury via inducing miR-21/DMBT1/NF-κB axis. Therefore, quercetin could be utilized as a potential compound to treat for allergic rhinitis.

Genetics and Epigenetics in Allergic Rhinitis

The pathogenesis of allergic rhinitis is associated with genetic, environmental, and epigenetic factors. Genotyping of single nucleotide polymorphisms (SNPs) is an advanced technique in the field of molecular genetics that is closely correlated with genome-wide association studies (GWASs) in large population groups with allergic diseases. Many recent studies have paid attention to the role of epigenetics, including alteration of DNA methylation, histone acetylation, and miRNA levels in the pathogenesis of allergic rhinitis. In this review article, genetics and epigenetics of allergic rhinitis, including information regarding functions and significance of previously known and newly-discovered genes, are summarized. Directions for future genetic and epigenetic studies of allergic rhinitis are also proposed.

Long non-coding RNA growth arrest-specific 5 and its targets, microRNA-21 and microRNA-140, are potential biomarkers of allergic rhinitis

Objective

Long non‐coding RNA growth arrest‐specific 5 (lnc‐GAS5) and its targets (microRNA [miR]‐21 and miR‐140) are involved in the development and progression of allergic rhinitis (AR). However, the correlation of lnc‐GAS5 with miR‐21 and miR‐140 and their associations with disease risk, symptom severity, and Th1/Th2 cytokines in AR remain unclear. Thus, this study aimed to investigate this topic.

Methods

In total, 120 patients with AR and 60 controls were recruited. Nasal‐mucosa tissues were collected from all participants. Lnc‐GAS5, its targets (miR‐21 and miR‐140), interferon (IFN)‐γ, interleukin (IL)‐2, IL‐4, and IL‐10 were detected by reverse‐transcription quantitative polymerase chain reaction.

Results

Lnc‐GAS5 was elevated, while miR‐21 and miR‐140 was downregulated in AR patients than in controls (p < 0.001). In AR patients, lnc‐GAS5 was negatively correlated with miR‐21 (p < 0.001), miR‐140 (p < 0.001), IFN‐γ (p = 0.019), and IL‐2 (p = 0.039) and positively correlated with IL‐4 (p = 0.004) and IL‐10 (p < 0.001), individual nasal symptom scores (INSSs) for itching, sneezing, and congestion (p < 0.05), and total nasal symptom score (TNSS) (p < 0.001). Moreover, miR‐21 and miR‐140 were negatively correlated with some INSSs, total TNSS score, and IL‐10 and positively correlated with IFN‐γ and IL‐2 (p < 0.05).

Conclusion

Lnc‐GAS5 is negatively correlated with that of its targets (miR‐21 and miR‐140) in AR; meanwhile, lnc‐GAS5, miR‐21, and miR‐140 are correlated with disease risk, symptom severity, and Th1/Th2 imbalance in AR, suggesting the potential of these biomarkers in the development and progression of AR.

MicroRNA and cyclooxygenase-2 in breast cancer

Cancer remains a major public health problem worldwide and the latest statistics show that breast cancer (BC) is among the most frequent in women. MicroRNAs (miRNAs; miRs) and cyclooxygenase-2 (COX-2) are new diagnostic and therapeutic biomarkers for monitoring BC. COX-2 is a prominent tumor-associated inflammatory factor highly expressed in human tumor cells, including BC. Expression of COX-2 contributes to tumor growth, metastasis and recurrence. MiRs are a group of short (~22 nucleotides), noncoding regulatory RNAs that downregulate gene expression post-transcriptionally and play vital roles in regulating cancer development and progression. Interestingly, there are a group of miRNAs differentially expressed in breast tumor tissue. Understanding the pathway linking miRNAs to COX-2 can provide novel insight for suppressing COX-2 expression via gene silencing thereby leading to the development of selective miRNA inhibitors. Further research can also reveal key intermediate players and their potential as therapeutic targets. Given the association between different miRNAs and COX-2 expression in BC, this review presents a comprehensive overview of the current literature concerning how miRNAs and COX-2 signaling interact in BC progression.

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.

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.

The correlation of long non-coding RNA NEAT1 and its targets microRNA (miR)-21, miR-124, and miR-125a with disease risk, severity, and inflammation of allergic rhinitis

The present study aimed to investigate the correlation of long non-coding RNA nuclear-enriched abundant transcript 1 (lncRNA NEAT1) with microRNA (miR)-21, miR-124, and miR-125a, and their associations with disease risk, severity, and inflammatory cytokines of allergic rhinitis (AR).Totally 70 AR patients and 70 non-atopic obstructive snoring patients (as controls) were recruited. Inferior turbinate mucosa samples were collected from all participants for lncRNA NEAT1, its targets (miR-21, miR-124, and miR-125a), interleukin (IL)-4, IL-6, IL-10, and IL-17 detection via reverse transcription quantitative polymerase chain reaction. Disease severity of AR patients was assessed using individual nasal symptom score (INSS) and total nasal symptom score (TNSS).LncRNA NEAT1 was upregulated, while miR-21, miR-124, and miR-125a were downregulated in AR patients compared with controls. Additionally, lncRNA NEAT1, miR-21, and miR-125a displayed good values in differentiating AR patients from controls, while miR-124 could only slightly differentiate AR patients from controls. In AR patients, lncRNA NEAT1 was negatively associated with miR-21 and miR-125a, but not miR-124. However, in controls, no correlation of lncRNA NEAT1 with miR-21, miR-124, or miR-125a was observed. Furthermore, in AR patients, lncRNA NEAT1 was positively, while miR-21 and miR-125a was negatively associated with INSS (rhinorrhea, itching, congestion scores), TNSS and inflammatory cytokines; however, correlation of miR-124 with INSS, TNSS, and inflammatory cytokines was slight.LncRNA NEAT1 and its targets (miR-21 and miR-125a) present close correlations with disease risk, severity, and inflammation of AR, suggesting their potential as biomarkers for AR assessment.

circARRDC3 contributes to interleukin‑13‑induced inflammatory cytokine and mucus production in nasal epithelial cells via the miR‑375/KLF4 axis

Allergic rhinitis (AR) is a common inflammatory disorder of the nasal mucosa. It is a major risk factor for asthma development, and uncontrolled AR can lead to the worsening of asthma symptoms, which affects the quality of life and productivity of patients. Circular RNAs (circRNA) were reported to be involved in the pathogenesis of AR. The aim of the present study was to investigate the functional role of circRNA arrestin domain-containing 3 (circARRDC3) in AR progression. circARRDC3 knockdown suppressed the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and eotaxin and mucin 5AC (MUC5AC) in IL-13-induced nasal epithelial cells. Moreover, circARRDC3 silencing promoted viability and suppressed apoptosis in IL-13-induced NECs. circARRDC3 targeted microRNA (miR)-375 and negatively regulated its expression. miR-375 inhibition reversed the effects of circARRDC3 knockdown on GM-CSF, eotaxin and MUC5AC expression levels, cell viability and cell apoptosis. In addition, miR-375 inhibited krueppel-like factor 4 (KLF4) expression through direct interaction, and miR-375 overexpression inhibited GM-CSF, eotaxin and MUC5AC expression levels, and cell apoptosis, which was abolished following KLF4 overexpression. In addition, circARRDC3, miR-375 and KLF4 were all dysregulated in the nasal mucosa of patients with AR. miR-375 expression was negatively correlated with circARRDC3 and KLF4 expression, and circARRDC3 expression was positively correlated with KLF4 expression. In conclusion, circARRDC3 contributed to the development of AR by regulating the miR-375/KLF4 axis. These findings may provide novel insights into the pathogenesis of AR.

An endothelial microRNA-1-regulated network controls eosinophil trafficking in asthma and chronic rhinosinusitis

BACKGROUND

Airway eosinophilia is a prominent feature of asthma and chronic rhinosinusitis (CRS), and the endothelium plays a key role in eosinophil trafficking. To date, microRNA-1 (miR-1) is the only microRNA known to be regulated in the lung endothelium in asthma models.

OBJECTIVE

We sought to determine the role of endothelial miR-1 in allergic airway inflammation.

METHODS

We measured microRNA and mRNA expression using quantitative RT-PCR. We used ovalbumin and house dust mite models of asthma. Endothelium-specific overexpression of miR-1 was achieved through lentiviral vector delivery or induction of a transgene. Tissue eosinophilia was quantified by using Congo red and anti-eosinophil peroxidase staining. We measured eosinophil binding with a Sykes-Moore adhesion chamber. Target recruitment to RNA-induced silencing complex was assessed by using anti-Argonaute2 RNA immunoprecipitation. Surface P-selectin levels were measured by using flow cytometry.

RESULTS

Serum miR-1 levels had inverse correlations with sputum eosinophilia, airway obstruction, and number of hospitalizations in asthmatic patients and sinonasal tissue eosinophilia in patients with CRS. IL-13 stimulation decreased miR-1 levels in human lung endothelium. Endothelium-specific overexpression of miR-1 reduced airway eosinophilia and asthma phenotypes in murine models and inhibited IL-13-induced eosinophil binding to endothelial cells. miR-1 recruited P-selectin, thymic stromal lymphopoietin, eotaxin-3, and thrombopoietin receptor to the RNA-induced silencing complex; downregulated these genes in the lung endothelium; and reduced surface P-selectin levels in IL-13-stimulated endothelial cells. In our asthma and CRS cohorts, miR-1 levels correlated inversely with its target genes.

CONCLUSION

Endothelial miR-1 regulates eosinophil trafficking in the setting of allergic airway inflammation. miR-1 has therapeutic potential in asthmatic patients and patients with CRS.

Evaluation of the Possible Role of miRNAs in Chemical Allergen Potency

Objectives

MicroRNAs (miRNAs) are short, endogenous noncoding RNA molecules that can bind to certain parts of target mRNAs, thereby regulating gene expression. Studies showed that miRNAs could be up- or downregulated in different allergic skin conditions but there is still need for further studies. The aim of this study was to investigate the expression of miRNAs in response to the common contact allergen Bandrowski's base (BB), the principal allergen in patients reacting to p-phenylenediamine (PPD).

Materials and Methods

The human promyelocytic cell line THP-1 was exposed to BB at a concentration of 1 μg/mL for 24, 48, and 72 h. The dose was selected from the results of cytotoxicity assays. RNA was purified and miRNA expression profile and real-time polymerase chain reaction (RTPCR) were performed to identify up- or downregulated miRNAs and confirm their modulations.

Results

Among the different modulated miRNAs, the upregulation of miRNA-155 and the downregulation of miRNA-21 were found to be important because these are related to immune system. This expression profile of miRNAs was also confirmed by RT-PCR.

Conclusion

These preliminary results showed that miR-155 and miR-21 may play a role in the pathogenesis of allergic contact dermatitis, but further studies are needed to clarify their definite roles.

Emerging role of non-coding RNAs in allergic disorders

RNA transcripts that not undergo translation into polypeptides recently came into focus of research. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) comprise the most important groups of these transcripts. LncRNAs have a length over 200 nucleotides and like mRNAs, have regulated transcription in a tissue specific manner. Biogenesis and function of lncRNAs is related to cell differentiation, response to stimuli and regulation of immune responses. LncRNAs can interact with both miRNAs and mRNAs. MiRNAs are characterized by a length of 22-24 nucleotides. MiRNAs regulate expression of genes at the post-transcriptional level. LncRNAs together with miRNAs are considered as regulators of the immune system. Alterations in their biogenesis is an important mechanism in the development immune related disorders. CircRNAs are products of aberrant maturation of protein-coding transcripts in a process of back-splicing, in which a single strand RNA molecule attains a closed circle shape. Despite a low expression, some circRNA were found to titrate miRNAs and interfere with maturation of legitimate protein-coding transcripts. We summarize the current knowledge on the role of non-coding transcripts in allergic disorders: asthma, atopic dermatitis, allergic rhinitis and urticaria. The reviewed data suggest lncRNA and miRNAs as therapeutic targets and biomarkers of allergic disorders.

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.

MicroRNAs: Potential Biomarkers and Targets of Therapy in Allergic Diseases?

MicroRNAs (miRNAs) are small non-coding RNA molecules that are 18-22 nucleotides long and highly conserved throughout evolution. Currently, they are considered one of the fundamental regulatory mechanisms of genes expression. It has been demonstrated that miRNAs are involved in many biologic processes, such as signal transduction, cell proliferation and differentiation, apoptosis and stress responses. More recently, the role of miRNA has also been revealed in numerous immunological and inflammatory disorders, including allergic inflammation. Specific miRNA profiles were demonstrated in asthma, allergic rhinitis and atopic dermatitis. A core set of miRNAs involved in atopic diseases include upregulated miR-21, miR-223, miR-146a, miR-142-5p, miR-142-3p, miR-146b, miR-155 and downregulated let-7 family, miR-193b and miR-375. Most of the involved miRNAs increase secretion of Th2 cytokines (miR-1248, miR-146b), decrease secretion of Th1 cytokines (miR-513-5p, miR-625-5p) or promote differentiation of T cells towards Th2 (miR-21, miR-19a). In asthma miR-140-3p, miR-708 and miR-142-3p play a role in hyperplasia and hypertrophy of bronchial smooth muscle cells. Some single miRNAs or, more probably, their sets hold the promise for their use as biomarkers of atopic diseases. They are also promising target of future therapies.

Epigenetic changes: An emerging potential pharmacological target in allergic rhinitis

The importance of epigenetics has increased due to identification of its role in the pathophysiology of a number of diseases including allergic rhinitis. Amongst the different epigenetic changes in allergic retinitis, deacetylation of histone proteins by histone deacetylase (HDACs), hypermethylation of DNA by DNA methyltransferases (DNMT) and alteration in post-transcriptional process by the changes in the levels of miRNA are widely studied. Studies conducted related to allergic rhinitis have shown the elevation in the levels of HDAC1, 3 and 11 in the nasal epithelia and HDAC inhibitors have shown effectiveness in decreasing the symptoms of rhinitis. Their beneficial effects are attributed to restoration of the expression of TWIK-related potassium channel-1, correction of cytokine profile along with normalization of Th1/Th2 imbalance. Another epigenetic change due to increase in DNMT activity may induce DNA hypermethylation in CpG sites in the airway epithelial cells and CD4⁺ T-cells. The reduction in DNA methylation decreases allergic symptoms and normalizes the over-reactive immune system. Mechanistically, allergens may promote the hypermethylation in the promoter region of IFN-γ gene in CD4⁺ T cells via activation of ERK pathway to decrease the expression of IFN-γ. In allergic rhinitis patients, there is also a downregulation of certain miRNAs including miR-135a, miR-146a, miR-181a, miR-155 and upregulation of miRNA19a. This review discusses the studies describing the epigenetic changes taking place in the host cells in response to allergen along with possible mechanisms.

Bioinformatics-Based Approaches Predict That MIR-17-5P Functions in the Pathogenesis of Seasonal Allergic Rhinitis Through Regulating ABCA1 and CD69

OBJECTIVE

As the most prevalent type of rhinitis, allergic rhinitis is consisted of seasonal allergic rhinitis (SAR) and perennial allergic rhinitis. This study is carried out for revealing the mechanisms of SAR.

METHODS

Microarray data set GSE43523 (including 7 SAR nasal epithelial cells and 5 nonallergic control nasal epithelial cells) was extracted from Gene Expression Omnibus database. Based on limma package, differential expression analysis for the 2 groups was performed to obtain differentially expressed genes (DEGs). Using Multifaceted Analysis Tool for Human Transcriptome online tool, the functions involving the DEGs were predicted by enrichment analysis. Combined with Cytoscape software, protein-protein interaction (PPI) network was built and a significant network module was acquired. In addition, transcription factor (TF)-target and miRNA-target pairs were predicted using WebGestalt tool, and then TF-miRNA-target regulatory network was built by Cytoscape software.

RESULTS

There were 274 DEGs between rhinitis and control samples, including 144 upregulated genes and 130 downregulated genes. After PPI for the DEGs was built, a significant network module was identified. In the TF-miRNA-target regulatory network, ABCA1, CPEB4, CD69, MIR-17-5P, and CREB had higher degrees. Furthermore, both ABCA1 and CD69 were targeted by MIR-17-5P in the regulatory network.

CONCLUSION

CPEB4 and CREB might be implicated in the pathogenesis of SAR. Besides, MIR-17-5P might also act in SAR via targeting ABCA1 and CD69.

MicroRNAs for the pediatric otolaryngologist

The scope of pediatric otolaryngology is broad and encompasses a wide variety of diseases in which the fundamental phenotype-causing abnormality exists at the level of gene regulation and expression. Development of novel molecular biology instruments to diagnose disease, monitor treatment response, and prevent recurrence will facilitate the delivery of appropriate surgical and adjuvant medical treatments with lower morbidity. MicroRNAs (miRNAs) have emerged as a relatively new class of molecules that directly modulate gene expression and are abnormally expressed in a multitude of disease processes including those within the scope of pediatric otolaryngology. Functionally, miRNAs control multiple cellular functions including angiogenesis, cell proliferation, cell survival, genome stability, and inflammation. These short, non-protein coding RNA molecules are present and stable in tissue, blood, saliva, and urine, making them ideal disease biomarkers. The simple structure of miRNAs and their ability to directly modulate the expression of specific genes lends exciting therapeutic potential to miRNA-based therapies. Here we review the current literature of miRNAs as it relates to diseases within the scope of pediatric otolaryngology, and discuss their potential as diagnostic biomarkers and therapeutic targets.

miR-130a and miR-145 reprogram Gr-1+CD11b+ myeloid cells and inhibit tumor metastasis through improved host immunity

Tumor-derived soluble factors promote the production of Gr-1+CD11b+ immature myeloid cells, and TGFβ signaling is critical in their immune suppressive function. Here, we report that miR-130a and miR-145 directly target TGFβ receptor II (TβRII) and are down-regulated in these myeloid cells, leading to increased TβRII. Ectopic expression of miR-130a and miR-145 in the myeloid cells decreased tumor metastasis. This is mediated through a downregulation of type 2 cytokines in myeloid cells and an increase in IFNγ-producing cytotoxic CD8 T lymphocytes. miR-130a- and miR-145-targeted molecular networks including TGFβ and IGF1R pathways were correlated with higher tumor stages in cancer patients. Lastly, miR-130a and miR-145 mimics, as well as IGF1R inhibitor NT157 improved anti-tumor immunity and inhibited metastasis in preclinical mouse models. These results demonstrated that miR-130a and miR-145 can reprogram tumor-associated myeloid cells by altering the cytokine milieu and metastatic microenvironment, thus enhancing host antitumor immunity.

Chinese Society of Allergy Guidelines for Diagnosis and Treatment of Allergic Rhinitis

Allergic rhinitis (AR) is a global health problem that causes major illnesses and disabilities worldwide. Epidemiologic studies have demonstrated that the prevalence of AR has increased progressively over the last few decades in more developed countries and currently affects up to 40% of the population worldwide. Likewise, a rising trend of AR has also been observed over the last 2-3 decades in developing countries including China, with the prevalence of AR varying widely in these countries. A survey of self-reported AR over a 6-year period in the general Chinese adult population reported that the standardized prevalence of adult AR increased from 11.1% in 2005 to 17.6% in 2011. An increasing number of Journal Articles and imporclinical trials on the epidemiology, pathophysiologic mechanisms, diagnosis, management and comorbidities of AR in Chinese subjects have been published in international peer-reviewed journals over the past 2 decades, and substantially added to our understanding of this disease as a global problem. Although guidelines for the diagnosis and treatment of AR in Chinese subjects have also been published, they have not been translated into English and therefore not generally accessible for reference to non-Chinese speaking international medical communities. Moreover, methods for the diagnosis and treatment of AR in China have not been standardized entirely and some patients are still treated according to regional preferences. Thus, the present guidelines have been developed by the Chinese Society of Allergy to be accessible to both national and international medical communities involved in the management of AR patients. These guidelines have been prepared in line with existing international guidelines to provide evidence-based recommendations for the diagnosis and management of AR in China.

MiR-302e attenuates allergic inflammation in vitro model by targeting RelA

Allergic inflammation is the foundation of allergic rhinitis and asthma. Although microRNAs are implicated in the pathogenesis of various diseases, information regarding the functional role of microRNAs in allergic diseases is limited. Herein, we reported that microRNA-302e (miR-302e) serves as an important regulator of allergic inflammation in human mast cell line, HMC-1 cells. Our results showed that miR-302e is the dominant member of miR-302 family expressed in HMC-1 cells. Moreover, the expression of miR-302e was significantly decreased in response to phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187 or ovalbumin (OVA) stimulation. Overexpression of miR-302e blocked PMA/A23187 or OVA induced the increase in inflammatory cytokines levels, such as IL-1β, IL-6, tumor necrosis factor (TNF)-α and thymic stromal lymphopoietin, while miR-302 inhibition further promoted the release of these cytokines. Mechanistically, we found that miR-302e is a novel miRNA that targets RelA, a gene known to be involved in regulating inflammation, through binding to the 3'-UTR of RelA mRNA. Ectopic miR-302e remarkably suppressed the luciferase activity and expression of RelA, whereas down-regulation of miR-302e increased RelA luciferase activity and expression. Pharmacological inhibition of NF-κB reversed the augmented effect of miR-302e down-regulation on inflammatory cytokines level. Taken together, the present study demonstrates miR-302e limits allergic inflammation through inhibition of NF-κB activation, suggesting miR-302e may play an anti-inflammatory role in allergic diseases and function as a novel therapeutic target for the treatment of these diseases.

MicroRNA-17-5p aggravates lipopolysaccharide-induced injury in nasal epithelial cells by targeting Smad7

Background

Globally, rhinitis is one of the most common chronic disorders. Despite availability of drugs to manage the symptomatology of rhinitis, researchers still focus on identification of novel molecular targets for better management. MicroRNAs are implicated in many biological and pathological processes. However, the role of miR-17-5p in rhinitis remains unexplored. This study aimed to explore the role of miR-17-5p in lipopolysaccharide (LPS)-induced injury of nasal epithelial RPMI2650 cells and to elucidate the possible underlying molecular mechanism.

Results

LPS damaged RPMI2650 cells by inhibiting cell proliferation, promoting apoptosis, and stimulating the release of inflammatory cytokines. miR-17-5p expression was significantly increased in RPMI2650 cells following treatment with LPS. Furthermore, it was found that overexpression of miR-17-5p led to aggravation of LPS-induced injury. miR-17-5p negatively regulated expression of Smad7; overexpression of Smad7 protected the RPMI2650 cells by inactivating NF-κB and Wnt/β catenin pathways and vice versa.

Conclusions

Overexpression of miR-17-5p aggravated LPS-induced damage of RPMI2650 cells. Expression of Smad7 was negatively regulated by miR-17-5p; Smad7 expression inactivated NF-κB and Wnt/β catenin pathways.

MicroRNA-let-7e regulates the progression and development of allergic rhinitis by targeting suppressor of cytokine signaling 4 and activating Janus kinase 1/signal transducer and activator of transcription 3 pathway

The present study aimed to explore the microRNA-let-7e (miR-let-7e) expression in allergic rhinitis (AR), and to investigate the underlying molecular mechanisms. miR-let-7e expression in the nasal mucosa of mice and patients with AR were detected. The expression levels of three inflammatory factors, including histamine, immunoglobulin E and tumor necrosis factor-α (TNF-α), in the blood of AR mice and in interleukin (IL)-13-stimulated nasal epithelial cells (NECs) were also measured. Furthermore, the target gene of miR-let-7e was predicted and validated using a luciferase reporter assay. The expression levels of Janus kinase 1 (JAK1) and signal transducer and activator of transcription 3 (STAT3) were detected. The results demonstrated that miR-let-7e was downregulated in patients and mice with AR compared with the controls. In addition, the expression levels of inflammatory factors were higher in the blood of mice with AR compared with the control group, while miR-let-7e overexpression inhibited these levels in AR mice and IL-13-stimulated NECs. Furthermore, suppressor of cytokine signaling 4 (SOCS4) was revealed as a potential target gene of miR-let-7e and was negatively regulated by miR-let-7e. Overexpression of SOCS4 abrogated the anti-inflammatory activity of miR-let-7e overexpression. Finally, miR-let-7e overexpression activated the JAK1/STAT3 signaling pathway. In conclusion, miR-let-7e may serve an important role in the progression and development of AR, while overexpression of miR-let-7e had an anti-inflammatory effect by targeting SOCS4, which may be achieved by activation of the JAK1/STAT3 signaling pathway.

MicroRNAs in Allergic Disease

PURPOSE OF REVIEW

MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs that are increasingly being recognized as important epigenetic regulators. They have been implicated in the pathogenesis of many diseases including cancer, cardiovascular diseases, connective tissue diseases, and neuromuscular disorders.

RECENT FINDINGS

A few miRNAs have already been recognized as a core set of miRNAs important in allergic inflammation. These include let-7, miR-21, miR-142, and miR-146. This review aims to bring together some of the recent findings on how miRNAs regulate allergic inflammation with special focus on asthma, atopic dermatitis, allergic rhinitis, and eosinophilic esophagitis. We will also touch upon extracellular miRNAs and future perspective of this field of study.

MicroRNA-142-3p and let-7g Negatively Regulates Augmented IL-6 Production in Neonatal Polymorphonuclear Leukocytes

Neonatal PMN are qualitatively impaired in functions, yet they frequently reveal augmented inflammatory reactions during sepsis. Here, we hypothesized that PMN from newborns produce more IL-6 than those from adults under LPS stimulation, in which transcriptional or posttranscriptional regulation is involved in the altered expression. We found that neonatal PMN produced significantly higher IL-6 mRNA and protein than adult PMN. The higher IL-6 expression was not related to transcriptional but posttranscriptional regulation as the IL-6 expression was affected by the addition of cycloheximide but not actinomycin. To examine whether miRNA was involved in the IL-6 regulation of neonatal PMN, we surveyed differential displays of miRNAs that could potentially regulate IL-6 expression before and after LPS stimulation. Four miRNAs: hsa-miR-26a, hsa-miR-26b, hsa-miR-142-3p and hsa-let 7g decreased or increased after LPS treatment for 4 h. Further validation by qRT-PCR identified miR-26b, miR-142-3p and let-7g significantly changed in neonatal PMN after LPS stimulation. The functional verification by transfection of miR-142-3p and let-7g precursors into neonatal PMN significantly repressed the IL-6 mRNA and protein expression, suggesting that miR-142-3p and let-7g negatively regulate IL-6 expression in neonatal PMN. Modulation of miRNA expression may be used to regulate IL-6 production in newborns with altered inflammatory reactions.

MicroRNAs as regulators of drug abuse and immunity

MicroRNAs (miRNAs) are 20-22 nucleotide non-coding RNAs that participate in gene regulation. They bind to 3'-untranslated regions of their mRNA targets, inhibiting the transcripts' translation and/or destabilizing them. Chronic drug abuse induces changes of miRNAs expression in the brain, which is thought to contribute to addictive behaviors. Lots of miRNAs have been identified to play critical roles in the development of drug addiction. Moreover, miRNAs have been shown to play critical roles in a broad array of biologic processes, including regulation of the cell cycle, oncogenic transformation, immune cell regeneration and differentiation, and psychiatry disorders. We hypothesized that chronic drug abuse leads to aberrant expression of several miRNAs, and then aberrant miRNAs influence the innate and adaptive immunity, especially differentiation and function of T cells and B cells, through down-regulated miRNAs' target gene expression. Characterization of miRNA actions is important and has high potential effect for the management of drug addiction and immunity diseases. miRNAs are potential biomarkers, and the modulation of their expression can be used for therapeutic purposes.

Pediatric rhinitis risk factors

Rhinitis is a common global disorder that impacts on the quality of life of the sufferer and caregivers. Treatment for pediatric rhinitis is empirical and does not include a detailed history of the allergy triggers or allergy testing. Thus, allergen avoidance advice is not tailored to the child's sensitivities, which may result in adenoid hypertrophy. However, infant onset rhinitis, especially its relationship with respiratory viruses, remains to be further clarified. Rhinitis basically involves inflammation of the upper nasal lining, presenting typically with symptoms of runny nose (rhinorrhea), nasal blockage, and/or sneezing. While not typically fatal, it does impose significant health, psychological, and monetary burden to its sufferers, and is thus considered a global health problem. Previous findings showed that immunotherapy had significant clinical efficacy in children with allergic rhinitis. The present review article aims to highlight recent perspectives pertaining to the rhinitis risk factors especially in pediatric patients.

microRNA and Allergy

Allergy is a common hypersensitivity disorder of the immune system, which, along with other factors, is also subjected to regulation by microRNAs. The most common allergic diseases are allergic rhinitis, asthma, atopic dermatitis, and food allergy, which all are multifactorial and very heterogeneous conditions, highlighting the need for more individualized treatment techniques. More particular key questions in relation to allergic diseases are how microRNAs influence the differentiation, polarization, plasticity and functions of T helper and other immune cells, as well as the development of immune tolerance. In addition, microRNAs can affect allergic inflammation and tissue remodeling through their functions in epithelial and other tissue cells. Among immune system-related microRNAs, miR-21, miR-146a, and miR-155 are the most intensively studied and have convincingly been demonstrated to regulate immune responses and tissue inflammation in allergic diseases. Further characterization of microRNA functions is important, as similar to other conditions, the modulation of microRNA expression could potentially be used for therapeutic purposes in allergic diseases in the future. In addition, miRNAs could be implemented as biomarkers for endotyping complex allergic conditions.

MicroRNA in United Airway Diseases

The concept of united airway diseases (UAD) has received increasing attention in recent years. Sustained and increased inflammation is a common feature of UAD, which is inevitably accompanied with marked gene modification and tight gene regulation. However, gene regulation in the common inflammatory processes in UAD remains unclear. MicroRNA (miRNA), a novel regulator of gene expression, has been considered to be involved in many inflammatory diseases. Although there are an increasing number of studies of miRNAs in inflammatory upper and lower airway diseases, few miRNAs have been identified that directly link the upper and lower airways. In this article, therefore, we reviewed the relevant studies available in order to improve the understanding of the roles of miRNAs in the interaction and pathogenesis of UAD.

Regulation of IL-4 Expression in Immunity and Diseases

IL-4 was first identified as a T cell-derived growth factor for B cells. Studies over the past several decades have markedly expanded our understanding of its cellular sources and function. In addition to T cells, IL-4 is produced by innate lymphocytes, such as NTK cells, and myeloid cells, such as basophils and mast cells. It is a signature cytokine of type 2 immune response but also has a nonimmune function. Its expression is tightly regulated at several levels, including signaling pathways, transcription factors, epigenetic modifications, microRNA, and long noncoding RNA. This chapter will review in detail the molecular mechanism regulating the cell type-specific expression of IL-4 in physiological and pathological type 2 immune responses.

Intranasal Administration of Lentiviral miR-135a Regulates Mast Cell and Allergen-Induced Inflammation by Targeting GATA-3

Mast cell (MC) degranulation is the foundation of the acute phase of allergic rhinitis (AR). Previously, downregulation of GATA binding protein 3 (GATA-3) was shown to suppress MC activation in an AR mouse model. Binding of microRNA-135a (miR-135a) to GATA-3 was also observed, and overexpression of this miRNA decreased GATA-3 mRNA and protein expression. However, the effects of miR-135a on MCs during AR are currently unknown. In the present study, we utilized a lentiviral (LV) vector to intranasally administer miR-135a to ovalbumin (OVA)-sensitized AR mice. Following miR-135a treatment, the total serum IgE concentration observed during AR was significantly reduced. In the nasal mucosa, the expression of T-box expressed in T cells (T-bet) was higher, whereas that of GATA-3 was lower in the AR mice following miRNA treatment. Notably, during AR, the ratio of type 1 T-helper cells (Th1) to type 2 (Th2) cells in the spleen is unbalanced, favoring Th2. However, administering miR-135a to the AR mice appeared to balance this ratio by increasing and decreasing the percentage of Th1 and Th2 cells, respectively. MiR-135a also appeared to strongly suppress the infiltration of eosinophils and MCs into the nasal mucosa, and it was specifically localized in the MCs, suggesting that its influence is modulated through regulation of GATA-3 in these cells. Additional work identifying the full therapeutic potential of miR-135a in the treatment of AR and diseases involving allergen-induced inflammation is warranted.

Altered microRNA Expression Profiles of Extracellular Vesicles in Nasal Mucus From Patients With Allergic Rhinitis

Purpose

Allergic rhinitis (AR) is an inflammatory disorder of the upper airway. Exosomes or extracellular vesicles are nanosized vesicles of endosomal origin released from inflammatory and epithelial cells that have been implicated in allergic diseases. In this study, we characterized the microRNA (miRNA) content of exosomes in AR.

Methods

Extracellular vesicles were isolated from nasal mucus from healthy control subjects (n=10) and patients with severe AR (n=10). Vesicle RNA was analyzed by using a TaqMan microRNA assays Human Panel-Early Access kit (Applied Biosystems, Foster City, CA, USA) containing probes for 366 human miRNAs, and selected findings were validated with quantitative RT-PCR. Target prediction and pathway analysis for the differentially expressed miRNAs were performed using DIANA-mirPath.

Results

Twenty-one vesicle miRNAs were up-regulated and 14 miRNAs were under-regulated significantly (P<0.05) in nasal mucus from AR patients when compared to healthy controls. Bioinformatic analysis by DIANA-mirPath demonstrated that 32 KEGG biological processes were significantly enriched (P<0.05, FDR corrected) among differentially expressed vesicle miRNA signatures. Among them, the B-cell receptor signaling pathway (P=3.709E-09), the natural killer cell-mediated cytotoxicity (P=8.466E-05), the T-cell receptor signaling pathway (P=0.00075), the RIG-I-like receptor signaling pathway (P=0.00127), the Wnt signaling pathway (P=0.00130), endocytosis (P=0.00440), and salivary secretion (P=0.04660) were the most prominent pathways enriched in quantiles with differential vesicle miRNA patterns. Furthermore, miR-30-5p, miR-199b-3p, miR-874, miR-28-3p, miR-203, and miR-875-5p, involved in B-cell receptor and salivary secretion signaling pathways, were selected for validation using independent samples from 44 AR patients and 20 healthy controls. MiR-30-5p and miR-199b-3p were significantly increased in extracellular vesicles from nasal mucus when compared to healthy controls, while miR-874 and miR-28-3p were significantly down-regulated. In addition, miRNA-203 was significantly increased in AR patients, while miRNA-875-5p was found to be significantly decreased in AR patients.

Conclusions

This study demonstrated that vesicle miRNA may be a regulator for the development of AR.

miR-21 in ischemia/reperfusion injury: a double-edged sword?

MicroRNAs (miRNAs or miRs) are endogenous, small RNA molecules that suppress expression of targeted mRNA. miR-21, one of the most extensively studied miRNAs, is importantly involved in divergent pathophysiological processes relating to ischemia/reperfusion (I/R) injury, such as inflammation and angiogenesis. The role of miR-21 in renal I/R is complex, with both protective and pathological pathways being regulated by miR-21. Preconditioning-induced upregulation of miR-21 contributes to the protection against subsequent renal I/R injury through the targeting of genes such as the proapoptotic gene programmed cell death 4 and interactions between miR-21 and hypoxia-inducible factor. Conversely, long-term elevation of miR-21 may be detrimental to the organ by promoting the development of renal interstitial fibrosis following I/R injury. miR-21 is importantly involved in several pathophysiological processes related to I/R injury including inflammation and angiogenesis as well as the biology of stem cells that could be used to treat I/R injury; however, the effect of miR-21 on these processes in renal I/R injury remains to be studied.

Regulatory effect of microRNA-135a on the Th1/Th2 imbalance in a murine model of allergic rhinitis

Allergic rhinitis (AR) is primarily caused by a T helper cell (Th)1/Th2 imbalance. In a murine AR model of a previous study, the serum ovalbumin (OVA)-sIgE concentration was high, whereas microRNA (miR)-135a was lowly expressed in the nasal mucosa. The abnormal expression pattern of miR-135a coincided with highly expressed endogenous factors, including GATA binding protein (GATA)-3 and interleukin (IL)-4, and lowly expressed factors, including T-box expressed in T cells (T-bet) and interferon (IFN)-γ. We hypothesized that miR-135a may play an important role in immune regulation in AR mice. In the present study, AR was induced by OVA in the mice. Two groups of the AR mice were treated with a miR-135a mimic and a mimic control, respectively. The serum and nasal mucosa were collected for analysis. Following miR-135a application, the serum OVA-sIgE concentration was significantly reduced. In the nasal mucosa, the expression levels of miR-135a were higher, the mRNA and protein expression levels of GATA-3 and IL-4 were lower, and the expression levels of T-bet and IFN-γ were higher. The miR-135a corrected the Th1/Th2 imbalance in the AR mice. Findings of this study may provide a basis for novel genetic treatments in addressing allergic diseases.

MicroRNA profiles discriminate among colon cancer metastasis

MicroRNAs are being exploited for diagnosis, prognosis and monitoring of cancer and other diseases. Their high tissue specificity and critical role in oncogenesis provide new biomarkers for the diagnosis and classification of cancer as well as predicting patients' outcomes. MicroRNAs signatures have been identified for many human tumors, including colorectal cancer (CRC). In most cases, metastatic disease is difficult to predict and to prevent with adequate therapies. The aim of our study was to identify a microRNA signature for metastatic CRC that could predict and differentiate metastatic target organ localization. Normal and cancer tissues of three different groups of CRC patients were analyzed. RNA microarray and TaqMan Array analysis were performed on 66 Italian patients with or without lymph nodes and/or liver recurrences. Data obtained with the two assays were analyzed separately and then intersected to identify a primary CRC metastatic signature. Five differentially expressed microRNAs (hsa-miR-21, -103, -93, -31 and -566) were validated by qRT-PCR on a second group of 16 American metastatic patients. In situ hybridization was performed on the 16 American patients as well as on three distinct commercial tissues microarray (TMA) containing normal adjacent colon, the primary adenocarcinoma, normal and metastatic lymph nodes and liver. Hsa-miRNA-21, -93, and -103 upregulation together with hsa-miR-566 downregulation defined the CRC metastatic signature, while in situ hybridization data identified a lymphonodal invasion profile. We provided the first microRNAs signature that could discriminate between colorectal recurrences to lymph nodes and liver and between colorectal liver metastasis and primary hepatic tumor.

Augmented miR-150 expression associated with depressed SOCS1 expression involved in dengue haemorrhagic fever

OBJECTIVE

Suppressors of cytokine signalling (SOCS) proteins regulate cytokine responses and control immune balance. The objective of our study was to determine whether the expression of SOCS1 and its potential regulatory microRNAs (miRNAs) in leukocytes is correlated to the development of dengue haemorrhagic fever (DHF).

METHODS

We performed a case-control study to investigate the SOCS1 and miRNA expression in leukocytes for patients with DF and DHF in a DENV-2 outbreak that occurred in Taiwan between 2002 and 2003. We performed reverse transcription polymerase chain reaction to evaluate the expression of SOCS1 and its regulatory miRNAs in mononuclear leukocytes obtained from patients with or without DHF. The reciprocal relationship between SOCS1 and miR-150 expression was validated in DENV-2-infected peripheral mononuclear cells (PBMCs).

RESULTS

SOCS1 expression and lower IFN-γ level were significantly reduced in DHF patients, but not in patients with DF. Elevated SOCS1 and reduced miR-150 levels were detected 24 h after DENV-2 infection in PBMCs. Transfection of a miR-150 mimic into CD14(+) cells infected with DENV-2 suppressed the induction of SOCS1 expression in a dose-dependent manner.

CONCLUSION

We demonstrate for the first time that augmented miR-150 expression with depressed SOCS1 expression in CD14(+) cells are associated with the pathogenesis of DHF.

Asthma epigenetics

Asthma is the most common chronic disease of childhood, and a growing body of evidence indicates that epigenetic variations may mediate the effects of environmental exposures on the development and natural history of asthma. Epigenetics is the study of mitotically or meiotically heritable changes in gene expression that occur without directly altering the DNA sequence. DNA methylation, histone modifications and microRNAs are major epigenetic variations in humans that are currently being investigated for asthma etiology and natural history. DNA methylation results from addition of a methyl group to the 5 position of a cytosine ring and occurs almost exclusively on a cytosine in a CpG dinucleotide. Histone modifications involve posttranslational modifications such as acetylation, methylation, phosphorylation and ubiquitination on the tails of core histones. MicroRNAs are short ~22 nucleotide long, non-coding, single-stranded RNAs that binds to complementary sequences in the target mRNAs, usually resulting in gene silencing. While many studies have documented relationships of environmental exposures that have been implicated in asthma etiology with epigenetic alterations, to date, few studies have directly linked epigenetic variations with asthma development. There are several methodological challenges in studying the epigenetics of asthma. In this chapter, the influence of epigenetic variations on asthma pathophysiology, methodological concerns in conducting epigenetic research and future direction of asthma epigenetics research are discussed.

MicroRNAs in allergy and asthma

microRNAs (miRNAs) are short, single-stranded RNA molecules that function together with the partner proteins and cause degradation of target mRNAs or inhibit their translation. A particular miRNA can have hundreds of targets; therefore, miRNAs cumulatively influence the expression of a large proportion of genes. The functions of miRNAs in human diseases have been studied since their discovery in mammalian cells approximately 12 years ago. However, the role of miRNAs in allergic disease has only very recently begun to be uncovered. The purpose of this review is to provide an overview of the functions of miRNAs involved in the development of allergic diseases. We describe here the functions of miRNAs that regulate Th2 polarization and influence general inflammatory and tissue responses. In addition, we will highlight findings about the functions of extracellular miRNAs as possible noninvasive biomarkers of diseases with heterogeneous phenotypes and complex mechanisms and briefly discuss advances in the development of miRNA-based therapeutics.

MicroRNA in chronic rhinosinusitis and allergic rhinitis

Inflammatory upper airway diseases, particularly chronic rhinosinusitis (CRS) and allergic rhinitis (AR), have a high worldwide prevalence. CRS and AR involve sustained and exaggerated inflammation that is associated with marked changes in gene and protein expression under tight regulation. A novel group of gene expression regulators is a class of short single-stranded RNA molecules termed microRNAs (miRNAs). miRNAs can cause gene silencing through degradation of target mRNAs or inhibition of translation. Dysregulated expression of miRNAs has been shown in various human diseases, such as cancer, inflammatory skin and bowel diseases, rheumatoid arthritis, and asthma. Although studies of miRNAs in inflammatory upper airway diseases are relatively new and few, emerging evidence implicates an involvement of miRNAs in shaping the inflammation pattern in upper airways. The purpose of this review is to provide an overview on our current understanding of miRNA expression and function in CRS and AR, and to underscore the potential for clinical usage of miRNAs in CRS and AR.

Diagnostic, functional, and therapeutic roles of microRNA in allergic diseases

Allergic inflammation is accompanied by the coordinated expression of a myriad of genes and proteins that initiate, sustain, and propagate immune responses and tissue remodeling. MicroRNAs (miRNAs) are a class of short single-stranded RNA molecules that posttranscriptionally silence gene expression and have been shown to fine-tune gene transcriptional networks because single miRNAs can target hundreds of genes. Considerable attention has been focused on the key role of miRNAs in regulating homeostatic immune architecture and acquired immunity. Recent studies have identified miRNA profiles in multiple allergic inflammatory diseases, including asthma, eosinophilic esophagitis, allergic rhinitis, and atopic dermatitis. Specific miRNAs have been found to have critical roles in regulating key pathogenic mechanisms in allergic inflammation, including polarization of adaptive immune responses and activation of T cells (eg, miR-21 and miR-146), regulation of eosinophil development (eg, miR-21 and miR-223), and modulation of IL-13-driven epithelial responses (eg, miR-375). This review discusses recent advances in our understanding of the expression and function of miRNAs in patients with allergic inflammation, their role as disease biomarkers, and perspectives for future investigation and clinical utility.

MicroRNAs: Essential players in the regulation of inflammation

Regulation of inflammatory responses is ensured by coordinated control of gene expression in participating immune system and tissue cells. One group of gene expression regulators, the functions of which have recently been started to be uncovered in relation to any type of inflammatory condition, is a class of short single-stranded RNA molecules termed microRNAs (miRNAs). miRNAs function together with partner proteins and mainly cause gene silencing through degradation of target mRNAs or inhibition of translation. A particular miRNA can have hundreds of target genes, and thereby miRNAs together influence the expression of a large proportion of proteins. The role of miRNAs in the immune system has been extensively studied since the discovery of miRNAs in mammalian cells approximately 10 years ago. The purpose of the current review is to provide an overview on the functions of miRNAs in the regulation of inflammation, with a specific focus on the mechanisms of allergic inflammation. Because recent studies clearly demonstrate the presence of extracellular miRNAs in body fluids and propose the involvement of miRNAs in cell-cell communication, we will also highlight findings about functions of extracellular miRNAs. The possible use of miRNAs as biomarkers, as well as miRNA-related novel treatment modalities, might open a new future for the diagnosis and treatment of many inflammatory conditions, including allergic diseases.

Epigenetics and childhood asthma: current evidence and future research directions

Asthma is the most common chronic disease of childhood, affecting one in eight children in the USA and worldwide. It is a complex disease, influenced by both environmental exposures and genetic factors. Although epigenetic modifications (DNA methylation, histone modification and miRNA) can affect transcriptional activity in multiple genetic pathways relevant for asthma development, very limited work has been carried out so far to examine the role of epigenetic variations on asthma development and management. This review provides a brief overview of epigenetic modifications, summarizes recent findings, and discusses some of the major methodological concerns that are relevant for asthma epigenetics.

Developments in the field of allergy in 2010 through the eyes of Clinical and Experimental Allergy

In 2010 over 200 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, letters, book reviews and of course at the heart of the journal, papers containing original data which have moved the field of allergy forward on a number of fronts. For the third year running the editors felt it would be of value to summarize the key messages contained in these papers as a snapshot of where the cutting edge of research into allergic disease is leading. We have broadly followed the sections of the journal, although this year the mechanistic articles are grouped together and the studies involving experimental models of disease are discussed throughout the paper. In the field of asthma and rhinitis phenotypes and biomarkers continue to a major pre-occupation of our authors. There is continued interest in mechanisms of inflammation and disordered lung function with the mouse model of asthma continuing to offer new insights. There is also a steady flow of papers investigating new therapies, including those derived from plants and herbs, although many are mechanistic with too few high quality clinical trials. The mechanisms involved in allergic disease are well covered with many strong papers using clinical material to ask relevant questions. Pro-pre and snybiotics continue to be of major interest to our authors and this remains a controversial and complicated field. The discipline of epidemiology has retained its interest in risk factors for the development of allergic disease with a view to refining and debating the reasons for the allergy epidemic. There is continued interest in the relationship between helminthic disease and allergy with a new twist in 2010 involving studies using infection with helminths as a potential treatment. The genetics of allergic disease continues to be very productive, although the field has moved on from only investigating single nucleotide polymorphisms of candidate genes to Genome Wide Association Studies and an increasing and welcome emphasis on gene-environment interactions. In the field of clinical allergy there is steady flow of papers describing patterns of drug allergy with renewed interest in reactions to contrast media, but food allergy is the major area of interest in this section of the journal. Lastly in the field of allergens there is a growing interest in the role of component resolved diagnosis in improving the diagnosis and management of allergic disease. Another excellent year, full of fascinating and high quality work, which the journal has been proud to bring to the allergy community.

miRNA-125b regulates TNF-α production in CD14+ neonatal monocytes via post-transcriptional regulation

Neonates, although deficient in cell immunity, frequently reveal sepsis with augmented proinflammatory reactions. Here, we found that neonatal monocytes produced significantly higher TNF-α mRNA and protein than adult monocytes. Assessment of the transcriptional factor found no significant difference of NF-κB p65 level between neonatal and adult monocytes. Addition of Act D to access the half-life of TNF-α mRNA revealed no significant difference of the LPS-induced TNF-α mRNA half-life between them, whereas CHX increased neonatal TNF-α mRNA significantly. This suggests that a post-transcriptional mechanism involves the augmentation of TNF-α production by neonatal monocytes. To examine whether miRNA was involved in the post-transcriptional regulation, differential displays of miRNA array between neonatal and adult MNCs were performed, along with the discovery of hsa-miR-103, hsa-miR-125b, hsa-miR-130a, hsa-miR-454-3p, and hsa-miR-542-3p, which were greater than a twofold decrease or increase after LPS treatment for 4 h. The functional validation identified that miR-125b decreased significantly in association with higher TNF-α expression by neonatal monocytes after LPS stimulation. Transfection of the miR-125b precursor into neonatal monocytes significantly repressed the TNF-α mRNA and protein expression, suggesting that miR-125b negatively regulates TNF-α expression in neonatal monocytes. Modulation of miRNA expression may be used to regulate TNF-α production in newborns with altered proinflammatory reactions.