Pleiotropic microRNA-21 in pulmonary remodeling: novel insights for molecular mechanism and present advancements

Cellular Transdifferentiation: A Crucial Mechanism of Fibrosis in Systemic Sclerosis

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology with a highly complex pathogenesis that despite extensive investigation is not completely understood. The clinical and pathologic manifestations of the disease result from three distinct processes: 1) Severe and frequently progressive tissue fibrosis causing exaggerated and deleterious accumulation of interstitial collagens and other extracellular matrix molecules in the skin and various internal organs; 2) extensive fibroproliferative vascular lesions affecting small arteries and arterioles causing tissue ischemic alterations; and 3) cellular and humoral immunity abnormalities with the production of numerous autoantibodies, some with very high specificity for SSc. The fibrotic process in SSc is one of the main causes of disability and high mortality of the disease. Owing to its essentially universal presence and the severity of its clinical effects, the mechanisms involved in the development and progression of tissue fibrosis have been extensively investigated, however, despite intensive investigation, the precise molecular mechanisms have not been fully elucidated. Several recent studies have suggested that cellular transdifferentiation resulting in the phenotypic conversion of various cell types into activated myofibroblasts may be one important mechanism. Here, we review the potential role that cellular transdifferentiation may play in the development of severe and often progressive tissue fibrosis in SSc.

Harnessing the power of miRNAs: The molecular architects of asthma pathogenesis and potential targets for therapeutic innovation

Asthma is a chronic non-communicable respiratory disease that is characterized by airway inflammation and hyperreactivity. Defective functions of airway smooth muscle and dysregulated signaling pathways play a crucial role in the pathogenesis of asthma. Anti-inflammatories and targeted therapy are mainly used for the treatment of asthma. Recent studies have investigated the role of non-coding RNAs, especially microRNAs (miRNAs; miR) in regulating gene expression and their involvement in the dysfunctional signaling pathways. In immune-mediated diseases, including asthma, miRNAs govern the actions of cells that form the airway structure and those responsible for the defense mechanisms in the bronchi and lungs. miRNAs control cell survival, proliferation, and growth, as well as the cells' capacity to produce and release chemokines and immune mediators. Moreover, miRNAs have an important role in the response to therapeutic interventions. Collectively, this review highlights the regulatory roles of miRNAs in modulating the different signaling pathways and therapeutic responses in asthma. Patients who suffer from asthma, particularly those with severe disease characteristics, may benefit from the prospective treatment options that include targeting miRNAs in order to reduce airway inflammation, hyperreactivity, and mucus production.

High Expression Levels of miR-21-5p in Younger Hospitalized COVID-19 Patients Are Associated with Mortality and Critical Disease

In COVID-19, critical disease and invasive mechanical ventilation (IMV) increase the risk of death, mainly in patients over 60 years of age.

OBJECTIVES

To find the relationship between miR-21-5p and miR-146a-5p in terms of the severity, IMV, and mortality in hospitalized COVID-19 patients younger than 55 years of age.

METHODS

The patients were stratified according to disease severity using the IDSA/WHO criteria for severe and critical COVID-19 and subclassified into critical non-survivors and critical survivors.

RESULTS

Ninety-seven severe/critical COVID-19 patients were included; 81.3% of the deceased were male and 18.8% were female. Higher expression miR-21-5p levels were associated as follows: severe vs. critical disease (p = 0.007, FC = 0.498), PaO₂/FiO₂ index, mild vs. severe (p = 0.027, FC = 0.558), and survivors vs. non-survivors (p = 0.03, FC = 0.463). Moreover, we identified correlations with clinical variables: CRP (rho = -0.54, p < 0.001), D-dimer (rho = -0.47, p < 0.05), related to damage in the kidney (rho = 0.60, p < 0.001), liver (rho = 0.41, p < 0.05), and lung (rho = 0.54, p < 0.001). Finally, miR-21-5p thresholds were calculated according to severity (8.191), IMV (8.191), and mortality (8.237); these values increased the risk of developing a critical disease (OR = 4.19), the need for IMV (OR = 5.63), and death (OR = 6.00).

CONCLUSION

Increased expression levels of miR-21-5p are related to worse outcome of COVID-19 in younger hospitalized patients.

Noncoding RNAs: Master Regulator of Fibroblast to Myofibroblast Transition in Fibrosis

Myofibroblasts escape apoptosis and proliferate abnormally under pathological conditions, especially fibrosis; they synthesize and secrete a large amount of extracellular matrix (ECM), such as α-SMA and collagen, which leads to the distortion of organ parenchyma structure, an imbalance in collagen deposition and degradation, and the replacement of parenchymal cells by fibrous connective tissues. Fibroblast to myofibroblast transition (FMT) is considered to be the main source of myofibroblasts. Therefore, it is crucial to explore the influencing factors regulating the process of FMT for the prevention, treatment, and diagnosis of FMT-related diseases. In recent years, non-coding RNAs, including microRNA, long non-coding RNAs, and circular RNAs, have attracted extensive attention from scientists due to their powerful regulatory functions, and they have been found to play a vital role in regulating FMT. In this review, we summarized ncRNAs which regulate FMT during fibrosis and found that they mainly regulated signaling pathways, including TGF-β/Smad, MAPK/P38/ERK/JNK, PI3K/AKT, and WNT/β-catenin. Furthermore, the expression of downstream transcription factors can be promoted or inhibited, indicating that ncRNAs have the potential to be a new therapeutic target for FMT-related 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.

Role of circulatory miRNA-21 and associated signaling pathways in the pathogenesis of pulmonary fibrosis among individuals recovered after COVID-19 infection

Introduction

Currently pulmonary fibrosis in post-COVID individuals represents a crucial milieu of investigation due to long-term associated complications and worse clinical outcome. Lack of studies in Indian population confers a crucial need for elucidating possible targets and mechanisms to explore better management and outcome. Hence, this study aimed to explore the role of circulating miRNA-21 in patients from South India after COVID-19 recovery, while targeting TGF-β signaling pathway involved in the development of pulmonary fibrosis.

Methods

This prospective, single centre, hospital-based study enrolled a total of 50 participants in the age group of 50 to 60 years including 25 non-infected controls and 25 patients who were recovered after 3–6 months of COVID-19 infection and presented radiological pulmonary abnormalities. Quantification of miRNA-21 and selected gene transcripts (TGF-β, Col1A2, Col3A1, and α-SMA) was performed in plasma samples of both patients and controls.

Results

Significantly increased expression levels of miRNA-21 was observed in patient samples compared to controls (4.50 ± 1.03 vs 12.60 ± 3.52, p < 0.0001) with 72.10% sensitivity and 80.10% specificity. Further, significantly increased levels of central fibrosis regulatory gene transcript TGF-β (0.56 ± 0.27 vs 1.83 ± 0.98), two crucial collagen transcripts Col1A2 (0.62 ± 0.19 vs 1.56 ± 1.00) and Col3A1 (0.61 ± 0.27 vs 1.54 ± 0.89), and α-SMA (0.46 ± 0.17 vs 1.20 ± 0.78) was observed in patients compared to controls. Western-blot analysis also showed almost similar observations at proteins levels.

Conclusion

Circulating miRNA-21 may provide crucial insights for elucidating TGF-β mediated pulmonary remodeling involved in the fibrosis development and achieve better clinical outcome for post-COVID patients after recovery, in real-time with high diagnostic accuracy.

The current landscape of microRNAs (miRNAs) in bacterial pneumonia: opportunities and challenges

MicroRNAs (miRNAs), which were initially discovered in Caenorhabditis elegans, can regulate gene expression by recognizing cognate sequences and interfering with the transcriptional or translational machinery. The application of bioinformatics tools for structural analysis and target prediction has largely driven the investigation of certain miRNAs. Notably, it has been found that certain miRNAs which are widely involved in the inflammatory response and immune regulation are closely associated with the occurrence, development, and outcome of bacterial pneumonia. It has been shown that certain miRNA techniques can be used to identify related targets and explore associated signal transduction pathways. This enhances the understanding of bacterial pneumonia, notably for “refractory” or drug-resistant bacterial pneumonia. Although these miRNA-based methods may provide a basis for the clinical diagnosis and treatment of this disease, they still face various challenges, such as low sensitivity, poor specificity, low silencing efficiency, off-target effects, and toxic reactions. The opportunities and challenges of these methods have been completely reviewed, notably in bacterial pneumonia. With the continuous improvement of the current technology, the miRNA-based methods may surmount the aforementioned limitations, providing promising support for the clinical diagnosis and treatment of “refractory” or drug-resistant bacterial pneumonia.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

Regulatory network identified by pulmonary transcriptome and proteome profiling reveals extensive change of tumor-related genes in microRNA-21 knockout mice

PURPOSE

MicroRNA-21 (miR-21) is a well-known oncomiR and plays key roles in regulating various biological processes related to pulmonary diseases, especially lung carcinoma. The regulatory roles and downstream targets of miR-21 remain far from well understood. We aimed to identify miR-21-gene regulatory network in lung tissue.

METHODS

Transcriptome and proteome analyses were performed on lung tissues from miR-21 knockout (KO) mice and their wildtype (WT) littermates. Differentially expressed genes (DEGs) and proteins (DEPs) between miR-21KO and WT were analyzed, and correlation analysis was performed between transcriptional and translational level. DEPs were used for prediction of miR-21 target genes and construction of co-expression network.

RESULTS

Comparing with WT mice, 820 DEGs and 623 DEPs were identified in lung tissues of miR-21KO mice. Upregulated DEGs and DEPs were both significantly enriched in pathways of metabolism of xenobiotics by cytochrome P450, drug metabolism, and chemical carcinogenesis. Of the 31 molecules commonly identified in DEGs and DEPs, 9 upregulated genes were tumor suppressor genes while 8 downregulated genes were oncogenes, and 12 genes showed closely positive correlation between mRNA and protein expression. Real-time PCR validation results were consistent with the omics data. Among the upregulated DEPs in miR-21KO mice, 21 genes were predicted as miR-21 targets. The miR-21 regulatory network was constructed by target genes and their highly co-expressed proteins, which identified the miR-21 target Itih4 as a hub gene.

CONCLUSION

MiR-21-gene regulatory network was constructed in mouse lung tissue. MiR-21KO resulted in extensive upregulation of tumor suppressor genes and downregulation of oncogenes.

OUP accepted manuscript

Acute lung injury has been reported following various chemotherapeutic agents administration. Several pathways for lung injury have been speculated however, the exact mechanism of the lung injury induced by methotrexate (MTX) is yet to be defined. The potential protective effect of Ginkgo biloba extract (GB), a Chinese herbal medicine, against MTX-induced lung injury is still not reported. Therefore, this study was performed to examine the possible implication of NLRP3 inflammasome and miRNA-21 in the pathogenesis of the MTX-induced lung injury as well as the protective role of GB in ameliorating the induced lung injury. Rats received GB (100 mg/kg/day, orally) for 10 days and MTX (20 mg/kg single dose, intraperitoneally) on the fifth day. MTX-induced lung injury was manifested by lung histopathology. MTX exhibited a marked increase in lung malondialdehyde beside a notable decrease in lung reduced glutathione. Moreover, MTX injection activated the lung NLRP3 inflammasome by significant upregulation of the NLRP3, ASC, caspase-1 lung mRNA expressions and protein levels in addition to lung NF-kBp65 protein expression, and miRNA-21 expression when compared with the normal control group. However, GB administration mitigated lung injury and inhibited the NLRP3 activation. This study is the first report to reveal the involvement of NLRP3 inflammasome in the pathogenesis of MTX-induced lung injury and also to show that the administration of GB alleviates the lung injury induced by MTX via suppressing the oxidative stress, restoring the antioxidant activity, blocking the NLRP3/ASC/Caspase-1 signaling and downregulating the NF-kBp65 protein expression ae well as miRNA-21 expression in lung tissue.

miRNAs, from Evolutionary Junk to Possible Prognostic Markers and Therapeutic Targets in COVID-19

The COVID-19 pandemic has been a public health issue around the world in the last few years. Currently, there is no specific antiviral treatment to fight the disease. Thus, it is essential to highlight possible prognostic predictors that could identify patients with a high risk of developing complications. Within this framework, miRNA biomolecules play a vital role in the genetic regulation of various genes, principally, those related to the pathophysiology of the disease. Here, we review the interaction of host and viral microRNAs with molecular and cellular elements that could potentiate the main pulmonary, cardiac, renal, circulatory, and neuronal complications in COVID-19 patients. miR-26a, miR-29b, miR-21, miR-372, and miR-2392, among others, have been associated with exacerbation of the inflammatory process, increasing the risk of a cytokine storm. In addition, increased expression of miR-15b, -199a, and -491 are related to the prognosis of the disease, and miR-192 and miR-323a were identified as clinical predictors of mortality in patients admitted to the intensive care unit. Finally, we address miR-29, miR-122, miR-155, and miR-200, among others, as possible therapeutic targets. However, more studies are required to confirm these findings.

HDAC8-inhibitor PCI-34051-induced exosomes inhibit human bronchial smooth muscle cell proliferation via miR-381-3p mediated TGFB3

The present study aimed to investigate the effects of PCI-34051-induced human bronchial epithelial cells (HBECs)-derived exosomes (PCI-Exo) on human bronchial smooth muscle cells (HBSMCs) and the key exosomal miRNAs involved in this process. Blank exosomes (Exo) and PCI-Exo were extracted from HBECs treated with PBS and PCI-34051, respectively. RNA-sequencing was performed to uncover the miRNA expression profile affected by PCI-Exo. The MTT, flow cytometry and TUNEL assays were performed to reveal the effect of PCI-34051 and PCI-Exo on the proliferation and apoptosis of HBSMCs. Western blotting and qRT-PCR were used for detecting protein and mRNA expression. A total of 25 exosomal miRNAs consisted of 17 down-regulated and eight up-regulated miRNAs were differentially expressed among PCI-Exo and Exo. Target genes of the exosomal miRNAs were mainly associated with signal transduction, cell adhesion, microRNAs in cancer, and ECM receptor interaction. miR-381-3p was identified as the most significant upregulated differential miRNA in PCI-Exo after qRT-PCR validation and could be transferred to HBSMCs by PCI-Exo. PCI-Exo treatment inhibited the proliferation but induced the apoptosis of HBSMCs. TGFβ3 was identified as a target gene of miR-381-3p which could directly bind to the 3'UTR of TGFβ3 mRNA. After transfecting the miR-381-3p mimic into HBSMCs, the proliferation inhibition and apoptosis rate of HBSMCs was significantly increased, and siTGFβ3 transfection showed similar effects. Moreover, miR-381-3p overexpression could not only decrease the expression of α-SMA, FN1 and collagen I but also increase that of E-cadherin in HBSMCs. Our findings suggested that PCI-Exo could hinder the proliferation and obviously induce the apoptosis of HBSMCs, and its mechanisms might partly be attributable to the reduction of TGFβ3 level by up-regulating exosomal miR-381-3p expression. These results may be vital for the treatment of lung related-diseases, especially asthma.

MiR-21 in the Cancers of the Digestive System and Its Potential Role as a Diagnostic, Predictive, and Therapeutic Biomarker

MicroRNAs (miRNAs) are small non-coding RNAs. They can regulate the expression of their target genes, and thus, their dysregulation significantly contributes to the development of cancer. Growing evidence suggests that miRNAs could be used as cancer biomarkers. As an oncogenic miRNA, the roles of miR-21 as a diagnostic and prognostic biomarker, and its therapeutic applications have been extensively studied. In this review, the roles of miR-21 are first demonstrated via its different molecular networks. Then, a comprehensive review on the potential targets and the current applications as a diagnostic and prognostic cancer biomarker and the therapeutic roles of miR-21 in six different cancers in the digestive system is provided. Lastly, a brief discussion on the challenges for the use of miR-21 as a therapeutic tool for these cancers is added.

MicroRNAs in shaping the resolution phase of inflammation

Inflammation is a host defense mechanism orchestrated through imperative factors - acute inflammatory responses mediated by cellular and molecular events leading to activation of defensive immune subsets - to marginalize detrimental injury, pathogenic agents and infected cells. These potent inflammatory events, if uncontrolled, may cause tissue damage by perturbing homeostasis towards immune dysregulation. A parallel host mechanism operates to contain inflammatory pathways and facilitate tissue regeneration. Thus, resolution of inflammation is an effective moratorium on the pro-inflammatory pathway to avoid the tissue damage inside the host and leads to reestablishment of tissue homeostasis. Dysregulation of the resolution pathway can have a detrimental impact on tissue functionality and contribute to the diseased state. Multiple reports have suggested peculiar dynamics of miRNA expression during various pro- and anti-inflammatory events. The roles of miRNAs in the regulation of immune responses are well-established. However, understanding of miRNA regulation of the resolution phase of events in infection or wound healing models, which is sometimes misconstrued as anti-inflammatory signaling, remains limited. Due to the deterministic role of miRNAs in pro-inflammatory and anti-inflammatory pathways, in this review we have provided a broad perspective on the putative role of miRNAs in the resolution of inflammation and explored their imminent role in therapeutics.

Integrative Network Analysis of Predicted miRNA-Targets Regulating Expression of Immune Response Genes in Bovine Coronavirus Infection

Bovine coronavirus (BCoV) infection that causes disease outbreaks among farm animals, resulting in significant economic losses particularly in the cattle industry, has the potential to become zoonotic. miRNAs, which are short non-coding segments of RNA that inhibits the expression of their target genes, have been identified as potential biomarkers and drug targets, though this potential in BCoV remains largely unknown. We hypothesize that certain miRNAs could simultaneously target multiple genes, are significantly conserved across many species, thereby demonstrating the potential to serve as diagnostic or therapeutic tools for bovine coronavirus infection. To this end, we utilized different existing and publicly available computational tools to conduct system analysis predicting important miRNAs that could affect BCoV pathogenesis. Eleven genes including CEBPD, IRF1, TLR9, SRC, and RHOA, significantly indicated in immune-related pathways, were identified to be associated with BCoV, and implicated in other coronaviruses. Of the 70 miRNAs predicted to target the identified genes, four concomitant miRNAs (bta-miR-11975, bta-miR-11976, bta-miR-22-3p, and bta-miR-2325c) were found. Examining the gene interaction network suggests IL-6, IRF1, and TP53 as key drivers. Phylogenetic analysis revealed that miR-22 was completely conserved across all 14 species it was searched against, suggesting a shared and important functional role. Functional annotation and associated pathways of target genes, such as positive regulation of cytokine production, IL-6 signaling pathway, and regulation of leukocyte differentiation, indicate the miRNAs are major participants in multiple aspects of both innate and adaptive immune response. Examination of variants evinced a potentially deleterious SNP in bta-miR-22-3p and an advantageous SNP in bta-miR-2325c. Conclusively, this study provides new insight into miRNAs regulating genes responding to BCoV infection, with bta-miR-22-3p particularly indicated as a potential drug target or diagnostic marker for bovine coronavirus.

miR-21 mediates nickel nanoparticle-induced pulmonary injury and fibrosis

We and other groups have demonstrated that exposure to nickel nanoparticles (Nano-Ni) results in severe and persistent lung inflammation and fibrosis, but the underlying mechanisms remain unclear. Here, we propose that miR-21 may play an important role in Nano-Ni-induced lung inflammation, injury, and fibrosis. Our dose- and time-response studies demonstrated that exposure of C57BL/6J (WT) mice to Nano-Ni resulted in upregulation of miR-21, proinflammatory cytokines, and profibrotic mediators. Histologically, exposure to Nano-Ni caused severe pulmonary inflammation and fibrosis. Based on the dose- and time-response studies, we chose a dose of 50 µg of Nano-Ni per mouse to compare the effects of Nano-Ni on WT with those on miR-21 KO mouse lungs. At day 3 post-exposure, Nano-Ni caused severe acute lung inflammation and injury that were reflected by increased neutrophil count, CXCL1/KC level, LDH activity, total protein concentration, MMP-2/9 protein levels and activities, and proinflammatory cytokines in the BALF or lung tissues from WT mice, which were confirmed histologically. Although Nano-Ni had similar effects on miR-21 KO mice, the above-mentioned levels were significantly lower than those in WT mice. Histologically, lungs from WT mice exposed to Nano-Ni had infiltration of a large number of polymorphonuclear (PMN) cells and macrophages in the alveolar space and interstitial tissues. However, exposure of miR-21 KO mice to Nano-Ni only caused mild acute lung inflammation and injury. At day 42 post-exposure, Nano-Ni caused extensive pulmonary fibrosis and chronic inflammation in the WT mouse lungs. However, exposure of miR-21 KO mice to Nano-Ni only caused mild lung fibrosis and chronic lung inflammation. Our results also showed that exposure to Nano-Ni caused upregulation of TGF-β1, phospho-Smad2, COL1A1, and COL3A1 in both WT and miR-21 KO mouse lungs. However, levels were significantly lower in miR-21 KO mice than in WT mice, except TGF-β1, which was similar in both kinds of mice. Decreased expression of Smad7 was observed in WT mouse lungs, but not in miR-21 KO mice. Our results demonstrated that knocking out miR-21 ameliorated Nano-Ni-induced pulmonary inflammation, injury, and fibrosis, suggesting the important role of miR-21 in Nano-Ni-induced pulmonary toxicity.

MicroRNA and ROS Crosstalk in Cardiac and Pulmonary Diseases

Reactive oxygen species (ROS) affect many cellular functions and the proper redox balance between ROS and antioxidants contributes substantially to the physiological welfare of the cell. During pathological conditions, an altered redox equilibrium leads to increased production of ROS that in turn may cause oxidative damage. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level contributing to all major cellular processes, including oxidative stress and cell death. Several miRNAs are expressed in response to ROS to mediate oxidative stress. Conversely, oxidative stress may lead to the upregulation of miRNAs that control mechanisms to buffer the damage induced by ROS. This review focuses on the complex crosstalk between miRNAs and ROS in diseases of the cardiac (i.e., cardiac hypertrophy, heart failure, myocardial infarction, ischemia/reperfusion injury, diabetic cardiomyopathy) and pulmonary (i.e., idiopathic pulmonary fibrosis, acute lung injury/acute respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, lung cancer) compartments. Of note, miR-34a, miR-144, miR-421, miR-129, miR-181c, miR-16, miR-31, miR-155, miR-21, and miR-1/206 were found to play a role during oxidative stress in both heart and lung pathologies. This review comprehensively summarizes current knowledge in the field.

Exosomal miRNAs in tumor microenvironment

Tumor microenvironment (TME) is the internal environment in which tumor cells survive, consisting of tumor cells, fibroblasts, endothelial cells, and immune cells, as well as non-cellular components, such as exosomes and cytokines. Exosomes are tiny extracellular vesicles (40-160nm) containing active substances, such as proteins, lipids and nucleic acids. Exosomes carry biologically active miRNAs to shuttle between tumor cells and TME, thereby affecting tumor development. Tumor-derived exosomal miRNAs induce matrix reprogramming in TME, creating a microenvironment that is conducive to tumor growth, metastasis, immune escape and chemotherapy resistance. In this review, we updated the role of exosomal miRNAs in the process of TME reshaping.

Effects of AntagomiRs on Different Lung Diseases in Human, Cellular, and Animal Models

INTRODUCTION

MiRNAs have been shown to play a crucial role among lung cancer, pulmonary fibrosis, tuberculosis (TBC) infection, and bronchial hypersensitivity, thus including chronic obstructive pulmonary disease (COPD) and asthma. The oncogenic effect of several miRNAs has been recently ruled out. In order to act on miRNAs turnover, antagomiRs have been developed.

MATERIALS AND METHODS

The systematic review was conducted under the PRISMA guidelines (registration number is: CRD42019134173). The PubMed database was searched between 1 January 2000 and 30 April 2019 under the following search strategy: (((antagomiR) OR (mirna antagonists) OR (mirna antagonist)) AND ((lung[MeSH Terms]) OR ("lung diseases"[MeSH Terms]))). We included original articles, published in English, whereas exclusion criteria included reviews, meta-analyses, single case reports, and studies published in a language other than English.

RESULTS AND CONCLUSIONS

A total of 68 articles matching the inclusion criteria were retrieved. Overall, the use of antagomiR was seen to be efficient in downregulating the specific miRNA they are conceived for. The usefulness of antagomiRs was demonstrated in humans, animal models, and cell lines. To our best knowledge, this is the first article to encompass evidence regarding miRNAs and their respective antagomiRs in the lung, in order to provide readers a comprehensive review upon major lung disorders.