Altered miR-155 Expression in Allergic Asthmatic Airways

MicroRNA expression and their molecular targets in food allergies: a systematic review

Introduction

MicroRNAs (miRs) play an essential role in adaptive and innate immune systems by regulating the development of immune cells. However, detailed studies of miRs' role in food allergies are scarce compared to those of other allergic or non- allergic diseases. This systematic review aims to study miRs expression and its role in food allergies (FAs) and determine the signature miRs in FAs.

Method

Research articles published since 2015 were selected from various databases: Scopus, PubMed, ScienceDirect, and Web of Science. Randomized clinical trials, observational clinical studies, and in vivo studies were assessed via the Cochrane Risk of Bias 2 tool, the Newcastle-Ottawa scale, and SYRCLE method, respectively. The characteristics of the included studies, population characteristics, and experimental details were extracted, and the data were synthesized narratively.

Result

MiRs expression had been investigated in the context of cow milk allergy (CMA) and peanut allergy (PA) through both in vivo studies and clinical trials. Clinical trials included allergies to multiple combined foods, individual foods (such as milk, peanut, and what), and drugs and venom, while in vivo studies were conducted on milk, egg, and peanut allergies. MiR-146a, miR- 155, and miR-30a-5p were common miRs between in vivo studies and clinical trials. Moreover, few miRs were commonly studied between different types of food allergies. In clinical trials, miR-143-3p was studied in peanut allergy and non-celiac wheat sensitivity (NCWS), and miR-155 was studied in CMA and egg allergy in in vivo studies. Furthermore, the same miRs varied on their molecular target and effect depending on the type of food allergy.

Discussion

The study on signature miRs and their molecular target determination for the therapeutic purpose of food allergy is in its initial stage. For individual food allergies, miRs determination via next-generation sequencing (NGS), their validation via polymerase chain reaction (PCR), and target molecule determination via RNA interference (RNAi) should be the focus of future studies in order to determine reliable signature miRs of food allergy.

Breath and Sputum Analyses in Asthmatic Patients: An Overview

Recent advancements in asthma management include non-invasive methodologies such as sputum analysis, exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO). These techniques offer a means to assess airway inflammation, a critical feature of asthma, without invasive procedures. Sputum analysis provides detailed insights into airway inflammation patterns and cellular composition, guiding personalized treatment strategies. EBC collection, reflecting bronchoalveolar lining fluid composition, provides a non-invasive window into airway physiology. FeNO emerges as a pivotal biomarker, offering insights into eosinophilic airway inflammation and aiding in asthma diagnosis, treatment monitoring, and the prediction of exacerbation risks. Despite inherent limitations, each method offers valuable tools for a more comprehensive assessment of asthma. Combining these techniques with traditional methods like spirometry may lead to more personalized treatment plans and improved patient outcomes. Future research is crucial to refine protocols, validate biomarkers, and establish comprehensive guidelines in order to enhance asthma management with tailored therapeutic strategies and improved patient outcomes.

Expression profiles of miRNAs in the lung tissue of piglets infected with Glaesserella parasuis and the roles of ssc-miR-135 and ssc-miR-155-3p in the regulation of inflammation

MicroRNAs (miRNAs) have been shown to play an important regulatory role in the process of pathogenic infection. However, the miRNAs that regulate the pathogenic process of G. parasuis and their functions are still unknown. Here, high-throughput sequencing was used to quantify the expression of miRNA in piglet lung tissue after G. parasuis XX0306 strain infection. A total of 25 differentially expressed microRNAs (DEmiRNAs) were identified. GO and KEGG pathway enrichment analysis showed that many of the functions of genes that may be regulated by DEmiRNA are related to inflammatory response and immune regulation. Further studies found that ssc-miR-135 may promote the expression of inflammatory factors through NF-κB signaling pathway. Whereas, ssc-miR-155-3p inhibited the inflammatory response induced by G. parasuis, and its regulatory mechanism remains to be further investigated. This study provides a valuable reference for revealing the regulatory effects of miRNAs on the pathogenesis of G. parasuis. DATA AVAILABILITY: The datasets generated during the current study are not publicly available due to this study is currently in the ongoing research stage, and some of the data cannot be made public sooner yet, but are available from the corresponding author on reasonable request.

MicroRNAs: Key modulators of inflammation-associated diseases

Inflammation is a multifaceted biological and pathophysiological response to injuries, infections, toxins, and inflammatory mechanisms that plays a central role in the progression of various diseases. MicroRNAs (miRNAs) are tiny, 19-25 nucleotides long, non-coding RNAs that regulate gene expression via post-transcriptional repression. In this review, we highlight the recent findings related to the significant roles of miRNAs in regulating various inflammatory cascades and immunological processes in the context of many lifestyle-related diseases such as diabetes, cardiovascular diseases, cancer, etc. We also converse on how miRNAs can have a dual impact on inflammatory responses, suggesting that regulation of their functions for therapeutic purposes may be disease-specific.

Air Pollution and microRNAs: The Role of Association in Airway Inflammation

Air pollution exposure plays a key role in the alteration of gene expression profiles, which can be regulated by microRNAs, inducing the development of various diseases. Moreover, there is also evidence of sensitivity of miRNAs to environmental factors, including tobacco smoke. Various diseases are related to specific microRNA signatures, suggesting their potential role in pathophysiological processes; considering their association with environmental pollutants, they could become novel biomarkers of exposure. Therefore, the aim of the present work is to analyse data reported in the literature on the role of environmental stressors on microRNA alterations and, in particular, to identify specific alterations that might be related to the development of airway diseases so as to propose future preventive, diagnostic, and therapeutic strategies.

Non-Coding RNAs in Pulmonary Diseases: Comparison of Different Airway-Derived Biosamples

Due to their structural conservation and functional role in critical signalling pathways, non-coding RNA (ncRNA) is a promising biomarker and modulator of pathological conditions. Most research has focussed on the role of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules have been investigated both in a cellular and an extracellular context. Sources of ncRNAs may include organ-specific body fluids. Therefore, studies on ncRNAs in respiratory diseases include those on sputum, bronchoalveolar lavage fluid (BALF) and exhaled breath condensate (EBC). It is worth identifying the limitations of these biosamples in terms of ncRNA abundance, processing and diagnostic potential. This review describes the progress in the literature on the role of ncRNAs in the pathogenesis and progression of severe respiratory diseases, including cystic fibrosis, asthma and interstitial lung disease. We showed that there is a deficit of information on lncRNAs and circRNAs in selected diseases, despite attempts to functionally bind them to miRNAs. miRNAs remain the most well-studied, but only a few investigations have been conducted on the least invasive biosample material, i.e., EBC. To summarise the studies conducted to date, we also performed a preliminary in silico analysis of the reported miRNAs, demonstrating the complexity of their role and interactions in selected respiratory diseases.

Serum exosome inflamma-miRs are surrogate biomarkers for asthma phenotype and severity

BACKGROUND

Asthma is a heterogeneous disease with several phenotypes, endotypes and severity degrees, in which different T-cell subpopulations are involved. These cells express specific miRNAs (i.e. inflamma-miRs) that can be released to serum in exosomes after activation and be used as biomarkers of underlying inflammation. Thus, we aim to evaluate specific T-cell miRNA signatures in serum exosomes from different subgroups of asthmatic patients.

METHODS

Samples from healthy donors (N = 30) and patients (N = 119) with different asthma endotypes (T2^high -Atopic/T2^high -Non-atopic/T2^low ) and severity degrees (mild/MA and moderate-severe/MSA) were used. Demographic, clinical, haematological and biochemical characteristics were collected. Twelve miRNAs previously associated with different Th subsets were preselected and their levels in serum exosome samples were measured using RTqPCR.

RESULTS

We detected five miRNAs with high confidence in serum exosomes: miR-16-5p, miR-21-5p, miR-126-3p, miR146a-5p and miR-215-5p. All of them, except miR-16-5p were upregulated in MSA patients compared to MA. A logistic regression model including each of these miRNAs was created to discriminate both conditions, rendering a ROC curve AUC of 0.896 (0.830-0.961). miR-21-5p and miR-126-3p, both involved in Th1/Th2 differentiation, were specifically augmented in T2^high -Atopic patients. Of note, all these changes were found in samples collected in autumn. On the contrary, IL-6^high patients with MSA, which were more obese, older, with higher neutrophil and basophil counts and TNF levels, displayed a decrease of miR-21-5p, miR-126-3p and miR-146a-5p.

CONCLUSION

Immune-related miRNAs, including miR-21-5p, miR-126-3p, miR-146a-5p and miR-215-5p, can be used as clinically relevant non-invasive biomarkers of the phenotype/endotype and severity of asthma.

miR-146a, miR-221, and miR-155 are Involved in Inflammatory Immune Response in Severe COVID-19 Patients

COVID-19 infection triggered a global public health crisis during the 2020-2022 period, and it is still evolving. This highly transmissible respiratory disease can cause mild symptoms up to severe pneumonia with potentially fatal respiratory failure. In this cross-sectional study, 41 PCR-positive patients for SARS-CoV-2 and 42 healthy controls were recruited during the first wave of the pandemic in Mexico. The plasmatic expression of five circulating miRNAs involved in inflammatory and pathological host immune responses was assessed using RT-qPCR (Reverse Transcription quantitative Polymerase Chain Reaction). Compared with controls, a significant upregulation of miR-146a, miR-155, and miR-221 was observed; miR-146a had a positive correlation with absolute neutrophil count and levels of brain natriuretic propeptide (proBNP), and miR-221 had a positive correlation with ferritin and a negative correlation with total cholesterol. We found here that CDKN1B gen is a shared target of miR-146a, miR-221-3p, and miR-155-5p, paving the way for therapeutic interventions in severe COVID-19 patients. The ROC curve built with adjusted variables (miR-146a, miR-221-3p, miR-155-5p, age, and male sex) to differentiate individuals with severe COVID-19 showed an AUC of 0.95. The dysregulation of circulating miRNAs provides new insights into the underlying immunological mechanisms, and their possible use as biomarkers to discriminate against patients with severe COVID-19. Functional analysis showed that most enriched pathways were significantly associated with processes related to cell proliferation and immune responses (innate and adaptive). Twelve of the predicted gene targets have been validated in plasma/serum, reflecting their potential use as predictive prognosis biomarkers.

T cell-intrinsic miR-155 is required for Th2 and Th17-biased responses in acute and chronic airway inflammation by targeting several different transcription factors

Asthmatic airway inflammation is divided into two typical endotypes: Th2-mediated eosinophilic and Th1- or Th17-mediated neutrophilic airway inflammation. The miRNA miR-155 has well-documented roles in the regulation of adaptive T-cell responses and innate immunity. However, no specific cell-intrinsic role has yet been elucidated for miR-155 in T cells in the course of Th2-eosinophilic and Th17-neutrophilic airway inflammation using actual in vivo asthma models. Here, using conditional KO (miR155^ΔCD4 cKO) mice that have the specific deficiency of miR-155 in T cells, we found that the specific deficiency of miR-155 in T cells resulted in fully suppressed Th2-type eosinophilic airway inflammation following acute allergen exposure, as well as greatly attenuated the Th17-type neutrophilic airway inflammation induced by repeated allergen exposure. Furthermore, miR-155 in T cells appeared to regulate the expression of several different target genes in the functional activation of CD4+ Th2 and Th17 cells. To be more precise, the deficiency of miR-155 in T cells enhanced the expression of c-Maf, SOCS1, Fosl2, and Jarid2 in the course of CD4+ Th2 cell activation, while C/EBPβ was highly enhanced in CD4+ Th17 cell activation in the absence of miR-155 expression. Conclusively, our data revealed that miR-155 could promote Th2 and Th17-mediated airway inflammation via the regulation of several different target genes, depending on the context of asthmatic diseases. Therefore, these results provide valuable insights in actual understanding of specific cell-intrinsic role of miR-155 in eosinophilic and neutrophilic airway inflammation for the development of fine-tune therapeutic strategies.

Emerging role of exosomes in the pathology of chronic obstructive pulmonary diseases; destructive and therapeutic properties

Chronic obstructive pulmonary disease (COPD) is known as the third leading cause of human death globally. Enhanced chronic inflammation and pathological remodeling are the main consequences of COPD, leading to decreased life span. Histological and molecular investigations revealed that prominent immune cell infiltration and release of several cytokines contribute to progressive chronic remodeling. Recent investigations have revealed that exosomes belonging to extracellular vesicles are involved in the pathogenesis of COPD. It has been elucidated that exosomes secreted from immune cells are eligible to carry numerous pro-inflammatory factors exacerbating the pathological conditions. Here, in this review article, we have summarized various and reliable information about the negative role of immune cell-derived exosomes in the remodeling of pulmonary tissue and airways destruction in COPD patients.

MicroRNAs: A Promising Tool for Asthma Diagnosis and Severity Assessment. A Systematic Review

Micro RNAs (miRNAs) are short, non-coding RNAs (Ribonucleic acids) with regulatory functions that could prove useful as biomarkers for asthma diagnosis and asthma severity-risk stratification. The objective of this systematic review is to identify panels of miRNAs that can be used to support asthma diagnosis and severity-risk assessment. Three databases (Medline, Embase, and SCOPUS) were searched up to 15 September 2020 to identify studies reporting differential expression of specific miRNAs in the tissues of adults and children with asthma. Studies reporting miRNAs associations in animal models that were also studied in humans were included in this review. We identified 75 studies that met our search criteria. Of these, 66 studies reported more than 200 miRNAs that are differentially expressed in asthma patients when compared to non-asthmatic controls. In addition, 16 studies reported 17 miRNAs that are differentially expressed with differences in asthma severity. We were able to construct two panels of miRNAs that are expressed in blood and can serve as core panels to further investigate the practicality and efficiency of using miRNAs as non-invasive biomarkers for asthma diagnosis and severity-risk assessment, respectively.

Dietary Acid Load Modulation of Asthma-Related miRNAs in the Exhaled Breath Condensate of Children

Individual nutrients and bioactive compounds have been implicated in the expression of microRNAs (miRNAs), which are related to inflammation and asthma. However, evidence about the impact of diet is scarce. Therefore, we aimed to assess the association between dietary acid load and asthma-related miRNA in the exhaled breath condensate (EBC) of school-aged children. This cross-sectional analysis included 150 participants aged 7 to 12 years (52% girls) from a nested case–control study, which randomly selected 186 children attending 71 classrooms from 20 public schools located in city of Porto, Portugal. Dietary data were collected by one 24 h-recall questionnaire. Dietary acid load was assessed using the potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores. Based on previous studies, eleven asthma-related miRNAs were chosen and analyzed in EBC by reverse transcription-quantitative real-time PCR. PRAL, NEAP and miRNAs were categorized as high or low according to the median. Logistic regression models were performed to assess the association between dietary acid load scores and miRNAs. Children in high dietary acid load groups (PRAL ≥ 14.43 and NEAP ≥ 55.79 mEq/day) have significantly increased odds of having high miR-133a-3p levels. In conclusion, higher dietary acid loads possibly modulate asthma-related miRNAs of school-aged children.

Role of MicroRNA-155 as a Potential Biomarker for Allergic Rhinitis in Children

Background

Allergic rhinitis (AR) is an inflammatory state categorized by a disturbance of immunoregulatory mechanisms. MicroRNA-155 (miRNA-155) has an essential role in regulating gene expression and can mediate the allergic TH2 process.

Objective

In this study, we aimed to evaluate the role of miR-155 as a biomarker in AR and correlate its level with the total nasal symptom score (TNSS) and the levels of serum interleukin-4 (IL-4).

Methods

This study included 90 children: 45 with pollen-induced AR and 45 healthy controls. Serum miR-155 expression levels were measured using quantitative real-time PCR. Human IL-4 ELIZA kits were used for the semiquantitative detection of the serum levels of IL-4. Receiver operating characteristic (ROC) curves were used to determine the best cutoff values for the studied parameters for the diagnosis of AR.

Results

The demographic characteristics of the two groups were matched with respect to age and sex. The AR case group included 23 (51.1%) males and 22 (48.9%) females, while the control group included 24 (53.3%) males and 21 (46.7%) females. The miR-155 level was increased in the serum of children with pollen-induced AR compared with controls (mean difference = 2.8, p < 0.001). A significant positive correlation between the serum expression level of miR-155 and TNSS in children with AR was detected (r = 0.494, p < 0.001). However, no significant correlation was identified between the expression of miR-155 and that of IL-4. At a cutoff value of 1.09, the sensitivity of miR-155 as a biomarker for AR was 100%, and the specificity was 71.1%.

Conclusion

MiR-155 expression levels were elevated in the serum of AR children. Therefore, miR-155 could be used as a biomarker in AR diagnosis.

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.

miR-33a-5p in small extracellular vesicles as non-invasive biomarker for oxaliplatin sensitivity in human colorectal cancer cells

microRNAs (miRNAs) contained in small extracellular vesicles (sEVs) are candidates for non-invasive biomarkers. Oxaliplatin (L-OHP) has been approved for advanced colorectal cancer (CRC) chemotherapy. However, the response to L-OHP differs among CRC patients. In addition, CRC cells often acquire the resistance to L-OHP. This study aimed at the prediction of L-OHP sensitivity by measuring extracellular miRNAs levels. Firstly, we compared intracellular miRNAs expressions in L-OHP-sensitive CRC cells (SW620 and HCT116 cells) with those in acquired and intrinsic L-OHP-resistant cells. In microarray and real-time RT-PCR analyses, the intracellular miR-33a-5p, miR-210–3p, and miR-224–5p expressions were lower in acquired and intrinsic L-OHP-resistant CRC cells than sensitive cells. Furthermore, in SW620 cells, L-OHP sensitivity was decreased by miR-33a-5p inhibitor. On the other hand, miR-210–3p or miR-224–5p inhibitor did not affect L-OHP sensitivity in SW620 cells. Secondly, the amount of miR-33a-5p, miR-210–3p, and miR-224–5p in sEVs was compared. The amount of miR-33a-5p and miR-210–3p in sEVs secreted from acquired and intrinsic L-OHP-resistant cells tended to be small. miR-224–5p was not detected in sEVs secreted from three types of CRC cells examined. To the best of our knowledge, this is the first study demonstrating that miR-33a-5p and/or miR-210–3p in sEVs would be candidates for biomarkers of L-OHP sensitivity. In particular, miR-33a-5p is a promising candidate because it would be directly involved in L-OHP sensitivity.

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miR-33a-5p was down-regulated in oxaliplatin-resistant colorectal cancer cells.

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Reduction of intracellular miR-33a-5p expression caused oxaliplatin resistance.

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miR-33a-5p amount in small extracellular vesicles from resistant cells was small.

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miR-33a-5p is a candidate for non-invasive biomarker of oxaliplatin sensitivity.

Exosomes: A Key Piece in Asthmatic Inflammation

Asthma is a chronic disease of the airways that has an important inflammatory component. Multiple cells are implicated in asthma pathogenesis (lymphocytes, eosinophils, mast cells, basophils, neutrophils), releasing a wide variety of cytokines. These cells can exert their inflammatory functions throughout extracellular vesicles (EVs), which are small vesicles released by donor cells into the extracellular microenvironment that can be taken up by recipient cells. Depending on their size, EVs can be classified as microvesicles, exosomes, or apoptotic bodies. EVs are heterogeneous spherical structures secreted by almost all cell types. One of their main functions is to act as transporters of a wide range of molecules, such as proteins, lipids, and microRNAs (miRNAs), which are single-stranded RNAs of approximately 22 nucleotides in length. Therefore, exosomes could influence several physiological and pathological processes, including those involved in asthma. They can be detected in multiple cell types and biofluids, providing a wealth of information about the processes that take account in a pathological scenario. This review thus summarizes the most recent insights concerning the role of exosomes from different sources (several cell populations and biofluids) in one of the most prevalent respiratory diseases, asthma.

Diet Modifications in Primary Prevention of Asthma. Where Do We Stand?

The steep increase in asthma prevalence, observed worldwide in recent decades, has created an urgent need to search for effective methods of its prevention. Among other environmental factors, changes in diet habits and the potential influence of individual food components on immunological processes have been extensively studied as a potential method of intervention in primary prevention of asthma. The preventive role of some nutrients has been confirmed: unpasteurized milk reduced the risk of asthma in epidemiological studies, vitamin D supplementation was effective in preventing the transient forms of wheezing in small children and high maternal intake of fish oil reduced the risk of persistent wheeze and asthma in children. However, not all studies provided consistent results, and many food ingredients are still pending for defining their role in asthma development. Moreover, a novel approach looking not only at single food ingredients, but the whole dietary patterns and diversity has recently been proposed. In this paper, we discuss the current role of nutrients in asthma primary prevention and the reasons for inconsistencies in the study results. We look at single diet components, but also the whole dietary patterns. We describe the proposed mechanisms of action at different stages of life, identify the role of modifiers and delineate future perspectives on the application of nutrients in targeting strategies for asthma primary prevention.

A comprehensive analysis of microRNAs as diagnostic biomarkers for asthma

Background:

It is unclear whether microRNAs could be a potential diagnostic biomarker for asthma or not. The objective of this study is to figure out the diagnostic value of microRNAs in asthma.

Methods:

Literature retrieval, screening of publications, specific data extraction, and quality evaluation were conducted according to the standard criteria. Stata 14.0 software was used to analyze the diagnostic value of microRNA for asthma, including the combined sensitivity (Sen), specificity (Spe), the area under the curve (AUC), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR).

Results:

A total of 72 studies, containing 4143 cases and 2188 controls, were included for this comprehensive analysis. None of the included publications were rated low in quality. We summarized that, compared with controls, more than 100 miRNAs were reported differently expressed in asthma, although the expression trends were inconsistent. Besides, there were five studies among these 72 articles that applied the diagnostic evaluation of microRNAs in asthma. We found that the pooled Sen, Spe, and AUC for the combination of miR-185-5p, miR-155, let-7a, miR-21, miR-320a, miR-1246, miR-144-5p, and miR-1165-3p in asthma were 0.87 (95%CI: 0.72–0.95), 0.84 (95%CI: 0.74–0.91), and 0.93 (95%CI: 0.89–0.94) individually, and the PLR, NLR, and DOR were 5.5 (95%CI: 3.1–9.7), 0.15 (95%CI: 0.07–0.36), and 35 (95%CI: 10–127) in asthma, respectively. In terms of subgroup analyses, we found that the Sen for these combination miRNAs from serum was higher than that in plasma, while the Spe in plasma worked better than that in serum. Furthermore, compared with children, the combination of above miRNAs from adults had higher Spe and similar Sen.

Conclusions:

From our analysis, the combination of miR-185-5p, miR-155, let-7a, miR-21, miR-320a, miR-1246, miR-144-5p, and miR-1165-3p from peripheral blood could potentially act as a diagnostic biomarker for asthma.

The reviews of this paper are available via the supplemental material section.

M2 Macrophage-Derived Exosomes Promote Angiogenesis and Growth of Pancreatic Ductal Adenocarcinoma by Targeting E2F2

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive tumors all over the world, has a generally poor prognosis, and its progression is positively correlated with the density of blood vessels. Recently, tumor-associated macrophages (TAMs) were proven to be beneficial for angiogenesis, but their mechanism of action remains unclear. Our study indicated that M2 macrophages were positively correlated with the microvessel density (MVD) of PDAC tissues, and M2 macrophage-derived exosomes (MDEs) could promote the angiogenesis of mouse aortic endothelial cells (MAECs) in vitro. At the same time, the M2 MDEs could also promote the growth of subcutaneous tumors and increase the vascular density of mice. Moreover, we also found that miR-155-5p and miR-221-5p levels in the M2 MDEs were higher than those in M0 MDEs, and they could be transferred into MAECs, as demonstrated by RNA sequencing (RNA-seq) and qPCR analysis. Our data confirmed the interaction between TAMs and the angiogenesis of PDAC by exosomes. Additionally, targeting the exosomal miRNAs derived from TAMs might provide diagnostic and therapeutic strategies for PDAC.

Innate lymphoid cells in isocyanate-induced asthma: role of microRNA-155

BACKGROUND

Occupational asthma, induced by workplace exposures to low molecular weight agents such as toluene 2,4-diisocyanate (TDI), causes a significant burden to patients and society. Little is known about innate lymphoid cells (ILCs) in TDI-induced asthma. A critical regulator of ILC function is microRNA-155, a microRNA associated with asthma.

OBJECTIVE

To determine whether TDI exposure modifies the number of ILCs in the lung and whether microRNA-155 contributes to TDI-induced airway inflammation and hyperresponsiveness.

METHODS

C57BL/6 wild-type and microRNA-155 knockout mice were sensitised and challenged with TDI or vehicle. Intracellular cytokine expression in ILCs and T-cells was evaluated in bronchoalveolar lavage (BAL) fluid using flow cytometry. Peribronchial eosinophilia and goblet cells were evaluated on lung tissue, and airway hyperresponsiveness was measured using the forced oscillation technique. Putative type 2 ILCs (ILC2) were identified in bronchial biopsies of subjects with TDI-induced occupational asthma using immunohistochemistry. Human bronchial epithelial cells were exposed to TDI or vehicle.

RESULTS

TDI-exposed mice had higher numbers of airway goblet cells, BAL eosinophils, CD4⁺ T-cells and ILCs, with a predominant type 2 response, and tended to have airway hyperresponsiveness. In TDI-exposed microRNA-155 knockout mice, inflammation and airway hyperresponsiveness were attenuated. TDI exposure induced IL-33 expression in human bronchial epithelial cells and in murine lungs, which was microRNA-155 dependent in mice. GATA3⁺CD3^- cells, presumably ILC2, were present in bronchial biopsies.

CONCLUSION

TDI exposure is associated with increased numbers of ILCs. The proinflammatory microRNA-155 is crucial in a murine model of TDI asthma, suggesting its involvement in the pathogenesis of occupational asthma due to low molecular weight agents.

MicroRNAs in chronic airway diseases: Clinical correlation and translational applications

MicroRNAs (miRNAs) are short single-stranded RNAs that have pivotal roles in disease pathophysiology through transcriptional and translational modulation of important genes. It has been implicated in the development of many diseases, such as stroke, cardiovascular conditions, cancers and inflammatory airway diseases. There is recent evidence that miRNAs play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD), and could help to distinguish between T2-low (non-eosinophilic, steroid-insensitive) versus T2-high (eosinophilic, steroid-sensitive) disease endotypes. As these are the two most prevalent chronic respiratory diseases globally, with rising disease burden, miRNA research might lead to the development of new diagnostic and therapeutic targets. Research involving miRNAs in airway disease is challenging because: (i) asthma and COPD are heterogeneous inflammatory airway diseases; there are overlapping but distinct inter- and intra-disease differences in the immunological pathophysiology, (ii) there exists more than 2000 known miRNAs and a single miRNA can regulate multiple targets, (iii) differential effects of miRNAs could be present in different cellular subtypes and tissues, and (iv) dysregulated miRNA expression might be a direct consequence of an indirect effect of airway disease onset or progression. As miRNAs are actively secreted in fluids and remain relatively stable, they have the potential for biomarker development and therapeutic targets. In this review, we summarize the preclinical data on potential miRNA biomarkers that mediate different pathophysiological mechanisms in airway disease. We discuss the framework for biomarker development using miRNA and highlight the need for careful patient characterization and endotyping in the screening and validation cohorts, profiling both airway and blood samples to determine the biological fluids of choice in different disease states or severity, and adopting an untargeted approach. Collaboration between the various stakeholders - pharmaceutical companies, laboratory professionals and clinician-scientists is crucial to reduce the difficulties and cost required to bring miRNA research into the translational stage for airway diseases.

Circulating microRNAs correlate to clinical parameters in individuals with allergic and non-allergic asthma

BACKGROUND

Asthma is a chronic airway disease affecting millions of people. Better methods to define asthma subgroups using clinical parameters and molecular biomarkers are crucial in the development of personalized medicine.

OBJECTIVE

The aim of this study was to determine if circulating microRNAs (miRNAs) may be used to distinguish well-defined asthma groups.

METHODS

Blood serum from 116 well-defined subjects, including healthy controls and individuals with allergic or non-allergic asthma, from the West Sweden Asthma Study were included. Serum was analyzed for circulating miRNA expression of miR-126, - 145, -146a, - 155, - 223, and -374a and eosinophil cationic protein (ECP). Correlations between clinical characteristics and circulating miRNA expression as well as potential miRNA gene targets were investigated.

RESULTS

A subset of miRNAs were differentially expressed between allergic and non-allergic asthmatic individuals. Alterations in expression of miR-155, -146a, -374a and - 145 were observed in allergic asthmatics in response to inhaled corticosteroid usage. Additionally, miR-223 and miR-374a expression varied in non-allergic asthmatics based on blood eosinophil numbers. Numerous clinical parameters, including lung function measurements, correlated with subsets of miRNAs. Finally, pathway analysis revealed a potential role for inhaled corticosteroid induced miRNAs in leukocyte regulation, IL-6 signaling and glucocorticoid response.

CONCLUSION

Circulating miRNA expression was altered in subjects with allergic and non-allergic asthma and correlated to clinical parameters including lung function and potential gene targets involved in immune processes. This combination of clinical and molecular data may be a basis for the further, more precise classification of asthma subgroups. Taken together, these findings would further asthma research and benefit future patients through the discovery of molecular mechanisms as well as identifying asthma subgroups contributing to the development of personalized medicine.

MicroRNA-155 Implication in M1 Polarization and the Impact in Inflammatory Diseases

Macrophages are known to have an impact in cytokine signaling in the myriad of organs in which they reside and are classically known to be either pro-inflammatory (M1), anti-inflammatory (M2). Different classes of signaling molecules influence these states, of which, microRNAs represent key modulators. These are short RNA species approximately 21 to 23 nucleotides long that generally act by binding to the 3' untranslated region of mRNAs, regulating their translation, and, thus, the quantity of protein they encode. From these species, microRNA-155 was observed to be of great importance for M1 polarization. Because of it's major implication in M1 polarization microRNA-155 was shown to be implicated in different inflammatory diseases. To name a few, microRNA-155 was shown to be modified in patients with asthma and to correlate with asthma symptoms in mouse model; it has been shown to modulate the activity of foam cells and influence the dimensions of the atherosclerotic plaque and it has also been shown to be of crucial influence in transducing the signal of LPS in septic shock. Because of this, the current review aims to offer an overview of the role of microRNA-155 in M1 polarization, the implication that this poses for the pathophysiology of inflammatory diseases and the potential therapeutic possibilities that this knowledge might bring. Currently, microRNA-155 has been used in clinical trials as a marker of inflammation, but the question remains if it's inhibition will be useful in inflammatory diseases, as other products might have a better cost/benefit ratio.

Aberrant MicroRNAomics in Pulmonary Complications: Implications in Lung Health and Diseases

Over the last few decades, evolutionarily conserved molecular networks have emerged as important regulators in the expression and function of eukaryotic genomes. Recently, miRNAs (miRNAs), a large family of small, non-coding regulatory RNAs were identified in these networks as regulators of endogenous genes by exerting post-transcriptional gene regulation activity in a broad range of eukaryotic species. Dysregulation of miRNA expression correlates with aberrant gene expression and can play an essential role in human health and disease. In the context of the lung, miRNAs have been implicated in organogenesis programming, such as proliferation, differentiation, and morphogenesis. Gain- or loss-of-function studies revealed their pivotal roles as regulators of disease development, potential therapeutic candidates/targets, and clinical biomarkers. An altered microRNAome has been attributed to several pulmonary diseases, such as asthma, chronic pulmonary obstructive disease, cystic fibrosis, lung cancer, and idiopathic pulmonary fibrosis. Considering the relevant roles and functions of miRNAs under physiological and pathological conditions, they may lead to the invention of new diagnostic and therapeutic tools. This review will focus on recent advances in understanding the role of miRNAs in lung development, lung health, and diseases, while also exploring the progress and prospects of their application as therapeutic leads or as biomarkers.

The Beneficial Effect of Farm Milk Consumption on Asthma, Allergies, and Infections: From Meta-Analysis of Evidence to Clinical Trial

The low prevalence of asthma and allergies in farm children has partially been ascribed to the consumption of raw cow's milk. A literature search identified 12 publications on 8 pertinent studies. A meta-analysis corroborated the protective effect of raw milk consumption early in life (<1 to 5 years, according to study) on asthma (odds ratio [OR], 0.58; 95% CI, 0.49-0.69), current wheeze (OR, 0.66; 95% CI, 0.55-0.78), hay fever or allergic rhinitis (OR, 0.68; 95% CI, 0.57-0.82), and atopic sensitization (OR, 0.76; 95% CI, 0.62-0.95). The effect particularly on asthma was observed not only in children raised on farms (OR, 0.62; 95% CI, 0.58-0.82) but also in children living in rural areas but not on a farm (OR, 0.60; 95% CI, 0.48-0.74). This demonstrates that the effect of farm milk consumption is independent of other farm exposures and that children not living on a farm can theoretically profit from this effect. Because of the minimal but real risk of life-threatening infections, however, consumption of raw milk and products thereof is strongly discouraged. Raw farm milk and industrially processed milk differ in many instances including removal of cellular components, manipulation of the fat fraction, and various degrees of heating. Preliminary evidence attributes the effect to heat-labile molecules and components residing in the fat fraction. The Milk Against Respiratory Tract Infections and Asthma (MARTHA) trial is currently testing the protective effect of microbiologically safe, minimally processed cow's milk against standard ultra-heat-treated milk in children from 6 months to 3 years with the primary outcome of an asthma diagnosis until age 5 years. If successful, this approach might provide a simple but effective prevention strategy.

Development and validation of exhaled breath condensate microRNAs to identify and endotype asthma in children

Detection and quantification of microRNAs (miRNAs) in exhaled breath condensate (EBC) has been poorly explored. Therefore we aimed to assess miRNAs in EBC as potential biomarkers to diagnose and endotype asthma in school aged children. In a cross sectional, nested case control study, all the asthmatic children (n = 71) and a random sample of controls (n = 115), aged 7 to 12 years, attending 71 classrooms from 20 local schools were selected and arbitrarily allocated to the development or validation set. Participants underwent skin-prick testing, spirometry with bronchodilation, had exhaled level of nitric oxide determined and EBC collected. Based on previous studies eleven miRNAs were chosen and analyzed in EBC by reverse transcription-quantitative real-time PCR. Principal component analysis was applied to identify miRNAs profiles and associations were estimated using regression models. In the development set (n = 89) two clusters of miRNAs were identified. After adjustments, cluster 1 and three of its clustered miRNAs, miR-126-3p, miR-133a-3p and miR-145-5p were positively associated with asthma. Moreover miR-21-5p was negatively associated with symptomatic asthma and positively associated with positive bronchodilation without symptoms. An association was also found between miR-126-3p, cluster 2 and one of its clustered miRNA, miR-146-5p, with higher FEF25-75 reversibility. These findings were confirmed in the validation set (n = 97) where two identical clusters of miRNAs were identified. Additional significant associations were observed between miR-155-5p with symptomatic asthma, negative bronchodilation with symptoms and positive bronchodilation without symptoms. We showed that microRNAs can be measured in EBC of children and may be used as potential biomarkers of asthma, assisting asthma endotype establishment.

Determining Immune and miRNA Biomarkers Related to Respiratory Syncytial Virus (RSV) Vaccine Types

Respiratory Syncytial Virus (RSV) causes serious respiratory tract illness and substantial morbidity and some mortality in populations at the extremes of age, i.e., infants, young children, and the elderly. To date, RSV vaccine development has been unsuccessful, a feature linked to the lack of biomarkers available to assess the safety and efficacy of RSV vaccine candidates. We examined microRNAs (miR) as potential biomarkers for different types of RSV vaccine candidates. In this study, mice were vaccinated with a live attenuated RSV candidate that lacks the small hydrophobic (SH) and attachment (G) proteins (CP52), an RSV G protein microparticle (GA2-MP) vaccine, a formalin-inactivated RSV (FI-RSV) vaccine or were mock-treated. Several immunological endpoints and miR expression profiles were determined in mouse serum and bronchoalveolar lavage (BAL) following vaccine priming, boost, and RSV challenge. We identified miRs that were linked with immunological parameters of disease and protection. We show that miRs are potential biomarkers providing valuable insights for vaccine development.

A Review of Macrophage MicroRNAs' Role in Human Asthma

There is an imbalance in asthma between classically activated macrophages (M1 cells) and alternatively activated macrophages (M2 cells) in favor of the latter. MicroRNAs (miRNAs) play a critical role in regulating macrophage proliferation and differentiation and control the balance of M1 and M2 macrophage polarization, thereby controlling immune responses. Here we review the current published data concerning miRNAs with known correlation to a specific human macrophage phenotype and polarization, and their association with adult asthma. MiRNA-targeted therapy is still in the initial stages, but clinical trials are under recruitment or currently running for some miRNAs in other diseases. Regulating miRNA expression via their upregulation or downregulation could show potential as a novel therapy for improving treatment efficacy in asthma.

Differential expression of miR-155 and Let-7a in the plasma of childhood asthma: Potential biomarkers for diagnosis and severity

BACKGROUND

MicroRNAs (miRNAs) are emerging gene expression regulators and their expression has been linked to various biological processes. However, the role of miRNAs in the regulation of allergic inflammatory disease still not clearly understood.

AIM

Our study was designed to investigate circulating miR-155 and Let-7a expression levels in the plasma of asthmatic children and healthy controls. Also, to correlate their expression levels to degree of severity of asthma as well as to IL-13 level and lung function parameters.

METHOD

Our study included 100 asthmatic children and 100 healthy children as control group. Plasma miR-155 and Let-7a expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

MicroRNA-155 expression was significantly increased in the plasma of asthmatic children than in control children. While, Let-7a expression was significantly lower in asthmatics than in control children. The relative levels of miR-155 and Let-7a were associated with degree of asthma severity. Receiver operating characteristic (ROC) curve analysis demonstrated that the levels of miR-155 and Let-7a were helpful for diagnosis of childhood asthma (AUC were 0.91 and 0.92, respectively), and in prediction of the severity of disease (AUC were 0.83 and 0.80, respectively). Plasma miRNA-155 was correlated positively with Il-13 levels and correlated negatively with FEV1and FVC. While, Let-7a was correlated negatively with Il-13 and correlated positively with FEV1 and FVC.

CONCLUSION

MicroRNA-155 and let-7a could be used as serological non-invasive biomarkers for diagnosis of asthma and degree of severity. Our results could be used for exploring the pathogenesis of asthma and help in selecting promising therapeutic modalities.

MicroRNA-155: A Master Regulator of Inflammation

MicroRNAs (miRNAs) are naturally occurring, highly conserved families of transcripts (∼22 nucleotides in length) that are processed from larger hairpin precursors. miRNAs primarily regulate gene expression by promoting messenger RNA (mRNA) degradation or repressing mRNA translation. miRNAs have been shown to be important regulators of a variety of cellular processes involving development, differentiation, and signaling. Moreover, various human diseases, including cancer and immune dysfunction, are associated with aberrant expression of miRNAs. This review will focus on how the multifunctional miRNA, miR-155, regulates inflammatory diseases, including cancer and pulmonary disorders, and also how miR-155 expression and biogenesis are regulated. We will also provide examples of miR-155-regulated networks in coordination with other noncoding RNAs, including long noncoding RNAs as well as coding mRNAs acting as competing endogenous RNAs.

Role of microRNA in severe asthma

The various roles of microRNAs (miRNAs) in the epigenetic regulation of human disease are gaining importance as areas of research, and a better understanding of these roles may identify targets for development of novel therapies for severe asthma. MiRNAs, a class of small non-coding RNAs that serve as post-transcriptional gene repressors, are recognized as critical components in regulating tissue homeostasis. Alteration in miRNA expression disrupts homeostasis and is an underlying mechanism for development of chronic respiratory diseases, including asthma. Differential profiles of miRNA expression are involved in inflammation and remodeling pathogenicity via activating airway structural cells and immune cells and inducing cytokine releases. miRNA action leads to asthma progression from mild to severe stages. Here, current knowledge of the heterogeneous roles of miRNAs in severe asthma, including biological mechanisms underlying Th2 and macrophage polarization, type 2 innate lymphoid cell (ILC2) biology regulation, steroid-resistant asthma phenotype, airway smooth muscle (ASM) dysfunction, and impaired anti-viral innate immune, are reviewed.

Isolation and profiling of plasma microRNAs: Biomarkers for asthma and allergic rhinitis

Chronic inflammatory diseases can be particularly challenging to diagnose and characterize, as inflammatory changes in tissue may not be present in blood. There is a crucial need to develop non-invasive biomarkers that would be useful in diagnosing disease and selecting medical therapies. For example, there are no blood tests to diagnose asthma, a common inflammatory lung disease. MicroRNA (miRNA) expression profiling in blood is emerging as a potentially sensitive and useful biomarker of many diseases. In particular, we have characterized a cost-effective PCR-based array technology to measure and profile circulating miRNAs in the plasma of patients with allergic rhinitis and asthma. Here, we describe the methods to isolate, quantify, and analyze miRNAs in the plasma of human subjects as well as ways to determine their diagnostic utility.

MicroRNAs in type 2 immunity

Type 2 immunity drives the pathology of allergic diseases and is necessary for expulsion of parasitic worms as well as having important implications in tumor progression. Over the last decade, a new research field has emerged describing a significant link between type 2 immunity and cancer development, called AllergoOncology. Thus, type 2 immune responses must be carefully regulated to mediate effective protection against damaging environmental factors, yet avoid excessive activation and immunopathology. Regulation of gene expression by microRNAs is required for normal behavior of most mammalian cells and has been studied extensively in the context of cancer. Although microRNA regulation of the immune system in cancer is well established and includes type 2 immune reactions in the tumor microenvironment, the involvement of microRNAs in these responses initiated by allergens, parasites or other environmental factors is just emerging. In this review, we focus on recent advances which increase the understanding of microRNA-mediated regulation of key mechanisms of type 2 immunity.

Macrophage polarization and allergic asthma

Allergic asthma is associated with airway inflammation and airway hyperresponsiveness. Macrophage polarization has been shown to have a profound impact on asthma pathogenesis. On exposure to local microenvironments, recruited macrophages can be polarized into either classically activated (or M1) or alternatively activated (or M2) phenotypes. Macrophage polarization has been heavily associated with development of asthma. The process of regulation of macrophage polarization involves an intricate interplay between various cytokines, chemokines, transcriptional factors, and immune-regulatory cells. Different signals from the microenvironment are controlled by different receptors on the macrophages to initiate various macrophage polarization pathways. Most importantly, there is an increased attention on the epigenetic changes (eg, microRNAs, DNA methylation, and histone modification) that impact macrophage functional responses and M1/M2 polarization through modulating cellular signaling and signature gene expression. Thus, modulation of macrophage phenotypes through molecular intervention by targeting some of those potential macrophage regulators may have therapeutic potential in the treatment of allergic asthma and other allergic diseases. In this review, we will discuss the origin of macrophages, characterization of macrophages, macrophage polarization in asthma, and the underlying mechanisms regarding allergen-induced macrophage polarization with emphasis on the regulation of epigenetics, which will provide new insights into the therapeutic strategy for asthma.

Overexpression of miR-155-5p Inhibits the Proliferation and Migration of IL-13-Induced Human Bronchial Smooth Muscle Cells by Suppressing TGF-β-Activated Kinase 1/MAP3K7-Binding Protein 2

Purpose

Molecular mechanisms leading to asthma is still ill-defined. Though the function of microRNAs (miRNAs) in asthma was previously reported, the involvement of miR-155 in important features of this disease remains unknown. The present study was designed to uncover the probable involvement of miR-155-5p in the proliferation and migration of IL-13-induced human bronchial smooth muscle cells (BSMCs) and the intrinsic regulatory mechanism.

Methods

The effects of different concentrations of IL-13 on the proliferation and migration of BSMCs as well as the expression of miR-155-5p and its predicted target transforming growth factor (TGF)-β-activated kinase 1/MAP3K7-binding protein 2 (TAB2) were investigated. The effects of miR-155-5p on the proliferation and migration of interleukin (IL)-13-induced BSMCs was determined in vitro using BSMCs transfected with miR-155 mimic/inhibitor and induced by a high concentration of IL-13. The quantitative real-time polymerase chain reaction (qRTPCR) was employed for determining the expression of miR-155-5p and TAB2. Western blotting was applied to analyze the expression of TAB2 at the protein level. Cell proliferation and migration were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Transwell assays, respectively.

Results

The proliferation and migration of BSMCs were dose-dependently increased with IL-13 treatment. Contrariwise, IL-13 dose-dependently inhibited the expression of miR-155-5p in BSMCs. Mechanistic studies showed that inhibition of miR-155-5p further promoted the stimulatory effects of IL-13, whereas overexpression of miR-155 significantly inhibited these effects. In silico studies and luciferase reporter assays indicated that TAB2 was a negatively regulated miR-155-5p target.

Conclusions

These results suggested that miR-155-5p-inhibit the IL-13-induced proliferation and migration of BSMCs by targeting TAB2 and that the IL-13/miR-155/TAB2 pathway could serve as a therapeutic target for pulmonary diseases, especially asthma.

Non-Coding RNAs in Pediatric Airway Diseases

Non-coding RNAs (ncRNAs) are involved in the regulation of numerous biological processes and pathways and therefore have been extensively studied in human diseases. Previous reports have shown that non-coding RNAs play a crucial role in the pathogenesis and aberrant regulation of respiratory diseases. The altered expression of microRNAs (miRNAs) and long non-coding RNAs in blood and also locally in sputum or exhaled breath condensate influences lung function, immune response, and disease phenotype and may be used for the development of biomarkers specific for airway disease. In this review, we provide an overview of the recent works studying the non-coding RNAs in airway diseases, with a particular focus on chronic respiratory diseases of childhood. We have chosen the most common chronic respiratory condition—asthma—and the most severe, chronic disease of the airways—cystic fibrosis. Study of the altered expression of non-coding RNAs in these diseases may be key to better understanding their pathogenesis and improving diagnosis, while also holding promise for the development of therapeutic strategies using the regulatory potential of non-coding RNAs.