Exosomes and Exosomal miRNA in Respiratory Diseases

Exosomes are nanosized vesicles released from every cell in the body including those in the respiratory tract and lungs. They are found in most body fluids and contain a number of different biomolecules including proteins, lipids, and both mRNA and noncoding RNAs. Since they can release their contents, particularly miRNAs, to both neighboring and distal cells, they are considered important in cell-cell communication. Recent evidence has shown their possible importance in the pathogenesis of several pulmonary diseases. The differential expression of exosomes and of exosomal miRNAs in disease has driven their promise as biomarkers of disease enabling noninvasive clinical diagnosis in addition to their use as therapeutic tools. In this review, we summarize recent advances in this area as applicable to pulmonary diseases

The miR-196a SNP Rs11614913 but not the miR-499 rs37464444 SNP is a risk factor for non-small cell lung cancer in an Iranian population

BACKGROUND: Globally, lung cancer represents a major cause of cancer-related deaths. The regulation of gene expression is modulated by small noncoding RNAs called miRNAs that can act as both tumor suppressors and oncogenes. The maturation, expression and binding to target mRNAs is affected by single nucleotide polymorphisms (SNPs) in miRNA genomic regions thereby contributing to cancer susceptibility. SNPs Rs11614913 in miR196a and Rs3746444 in miR-499 are implicated in the development of cancers such as non-small cell lung cancer (NSCLC) in non-Arabic subjects. MATERIALS AND METHODS: A small cohort of 204 participants including 104 lung cancer patients and 100 non-cancer controls subjects were enrolled into the study. The allele frequencies were determined by Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) and their correlation with lung cancer risk was determined. RESULTS: The miR-196a rs11614913 polymorphism increased the risk of NSCLC (CC vs. TT+TC: OR= 2.26, 95%CI= 1.28 - 3.98, P= 0.0046) in a dominant genetic model. No statistically significant association was found between the miR-499 rs37464444 polymorphism and NSCLC. CONCLUSION: The rs11614913 polymorphism in miR-196a, but not the miR-499 rs37464444 polymorphism, increased the risk of NSCLC. Further studies with larger sample sizes in correlation with functional outcomes at the cellular level should be undertaken

MiRNAs in tuberculosis: Their decisive role in the fate of TB

Tuberculosis (TB) is one of the most lethal global infectious diseases. Despite the availability of much higher levels of technology in health and medicine, tuberculosis still remains a serious global health problem. Mycobacterium tuberculosis has the capacity for prolonged survival inside macrophages by exploiting host metabolic and energy pathways and perturbing autophagy and apoptosis of infected cells. The mechanism(s) underlying this process are not completely understood but evidence suggests that mycobacteria subvert the host miRNA network to enable mycobacterial survival. We present here a comprehensive review on the role of miRNAs in TB immune escape mechanisms and the potential for miRNA-based TB therapeutics. Further validation studies are required to (i) elucidate the precise effect of TB on host miRNAs, (ii) determine the inhibition of mycobacterial burden using miRNA-based therapies and (iii) identify novel miRNA biomarkers that may prove useful in TB diagnosis and treatment monitoring

A bioinformatics analysis of exosomal microRNAs released following mycobacterial infection

Background: Tuberculosis (TB) still remains a major health threat worldwide. The current TB diagnostics are suboptimal, and there is a high clinical need for identifying novel biomarkers of disease prevalence. Circulating exosomes have been currently attractive as novel biomarkers in a wide range of pathological conditions. Methods: In this study, we performed bioinformatics analysis on the downstream targets of a dysregulated microRNA (miRNA) cluster induced by Bacillus Calmette–Guerin infection of human macrophages to provide greater understanding of their potential roles in disease pathogenesis. Results: Our analysis demonstrated that these dysregulated miRNAs have central roles in the host metabolic and energy pathways. Conclusion: This suggests that the host miRNA network is perturbed by Mycobacterium to re-patterning host metabolism machinery to favor its intracellular survival. The dysregulated miRNAs can be delivered to local and distal cells by exosomes and thereby modulate their function

Exosomal miRNAs and association with pulmonary tuberculosis

Introduction: Tuberculosis (TB) remains a major threat to human health. Due to the limited accuracy of the current TB diagnostic tests, it is critical to determine novel biomarkers for this disease. Circulating exosomes have been used as diagnostic biomarkers in various diseases. Objective of the Study: In this study, we examined the expression of miRNAs as biomarker candidates for the diagnosis of TB infection. Methods: Serum exosomes were isolated using the total exosome isolation (TEI) reagent (Invitrogen, Thermo Fisher Scientific Corporation, USA). Serum-derived exosomes were isolated from TB patients (25 new case of active TB) and matched control subjects (25 persons). The expression of miR-484, miR-425, and miR-96 was examined by RT-PCR. Results: The expression of miR-484, miR-425, and miR-96 were significantly increased in serum of TB patients which correlated with the TB infection level. After normalization to U6, a statistically significant upregulation of miR-484 (13 55 ± 3 44 − fold increase, p ≤ 0 01), miR-425 (6 84 ± 1 7 − fold increase, p ≤ 0 01), and miR-96 (2 37 ± 0 53 − fold increase, p ≤ 0 05) was demonstrated in TB patients in comparison to healthy controls. A receiver operating characteristic (ROC) curve analysis showed the diagnostic potency of each individual serum exosomal miRNA with an area under the curve AUC =072 for miR-484 (p<005), 0.66 for miR-425 (p<005), and 0.62 for miR-96 (p<005). Conclusion: These results demonstrate that exosomal miRNAs have diagnostic potential in active tuberculosis. The diagnostic power may be improved when combined with conventional diagnostic markers

In vitro effects of water-pipe smoke condensate on the endocytic activity of Type II alveolar epithelial cells (A549) with bacillus Calmette-Guérin.

OBJECTIVE/BACKGROUND: Tuberculosis (TB) is a major global health problem and poses immense threats to many populations. The association between tobacco smoke and TB has already been studied. Water-pipe smoking has become an increasing problem not only in Middle Eastern countries but also globally as it is considered by users as being safer than cigarettes. The presence of high levels of toxic substances in water-pipe smoke may be predisposing factors that enhance the incidence of pulmonary disorders in water-pipe smokers. For example, uncontrolled macropinocytosis occurs in alveolar epithelial cells following exposure to water-pipe smoke, which may predispose individuals to pulmonary infection. In this work, we studied the effects of water-pipe condense (WPC) on the internalization of Mycobacterium bovis (bacillus Calmette-Guérin [BCG]) by macropinocytosis in Type II alveolar epithelial cells (A549). METHODS: A549 cells were treated by WPC (4mg/mL) for 24 h, 48 h, 72 h, and 96 h, respectively. The effect on cell proliferation was studied using a methylthiazolyldiphenyl-tetrazolium bromide (MTT) reduction assay. Cells were exposed to fluorescein isothiocyanate (FITC)-dextran (1mg/mL; control) and FITC-BCG (multiplicity of infection, 10) for 20min at 37°C before their collection and the uptake of BCG-FITC was determined by flow cytometry. Similar experiments were performed at 4°C as a control. RESULTS: WPC (4mg/mL) after 72h (1.4±0.2-fold, p<0.05) and 96h (1.6±0.2-fold, p<0.05) hours increased the uptake of BCG-FITC. No effect on BCG-FITC uptake was observed at 24h or 48h. WPC also significantly increased the uptake of FITC-dextran (2.9±0.3-fold, p<0.05) after 96h. WPC also significantly decreased cell proliferation after 24h (84±2%), 48h (78±3%), 72h (64±2%, p<0.05), and 96h (45±2%, p<0.05). CONCLUSION: WPC exposure increased epithelial cells' permeability and death and enhanced their capacity for macropinocytosis. Our in vitro data suggest possible harmful effects of WPC on the ability of lung epithelial cells to phagocytose mycobacteria. Further studies will be conducted to understand the mechanism of action of WPC

Evaluation expression of miR-146a and miR-155 in non-small cell lung cancer patients

Background: Non−small-cell lung cancer (NSCLC) is the major type of lung cancer. MicroRNAs (miRNAs) are novel markers and targets in cancer therapy and can act as both tumor suppressors and oncogenes and affect immune function. The aim of this study was to investigate the expression of miR146a and miR155 in linked to blood immune cell phenotypes and serum cytokines in NSCLC patients. Methods: Thirty-three NSCLC patients and 30 healthy subjects were enrolled in this study. The allele frequencies of potential DNA polymorphisms were studied using polymerase chain reaction (PCR)–restriction fragment length polymorphism (PCR-RFLP) analysis in peripheral blood samples. Quantitative reverse transcription PCR (qRT-PCR) was used to measure the expression of miR-146a and miR-155 in peripheral blood mononuclear cells (PBMCs). Serum cytokine (IL-1β, IL-6, TNF-α, TGF-β, IL-4, IFN-γ) levels were determined by ELISA. The frequency of circulating CD3+CTLA-4+ and CD4+CD25+FOXP3+ (T regulatory cells/Treg) expression was measured by flow cytometry. Results: miR-146a was significantly downregulated in PBMC of NSCLC patients (P ≤ 0.001). Moreover, IL-6 and TGF-β levels were elevated in NSCLC patients (P ≤ 0.001, P ≤ 0.018, respectively). CD3+ CTLA-4+ and Treg cells frequencies were higher in patients than in control subjects (P ≤ 0.0001, P ≤ 0.0001, respectively). There was a positive correlation between miR-155 and IL-1β levels (r=0.567, p ≤ 0.001) and a negative correlation between miR-146a and TGF-β levels (r=-0.376, P ≤ 0.031) in NSCLC patients. No significant differences were found in the relative expression of miR-146a and miR-155, cytokine levels or immune cell numbers according to miR-146a and miR-155 (GG/GC/CC, TT/AT/AA) genotypes. However, there was a positive correlation between miR-146a and IL-1β levels (r=0.74, P ≤ 0.009) in GG subjects and a positive correlation between miR-146a expression and CD3+CTLA4+ cell frequency (r=0.79, P ≤ 0.01) in CC genotyped subjects. Conversely, a negative correlation between miR-146a expression and Treg cell frequency (r=−0.87, P ≤ 0.05) was observed with the GG genotype. A positive correlation between miR-155 and IL-1β expression (r=0.58, p ≤ 0.009) in the TT genotype and between miR-155 expression and CD3+CTLA-4 cell frequency (r=0.75, P ≤ 0.01) was observed in the AT genotype. Conclusions: The current data suggest that the miR-146a expression in PBMC and serum TGF-β and IL-1β levels may act as blood markers in NSCLC patients. Further study is needed to elucidate the link between immune cells and serum miR146 at early disease stages

The roles of miRNAs as potential biomarkers in lung diseases.

MicroRNAs (miRNAs) are small non-coding RNAs which can act as master regulators of gene expression, modulate almost all biological process and are essential for maintaining cellular homeostasis. Dysregulation of miRNA expression has been associated with aberrant gene expression and may lead to pathological conditions. Evidence suggests that miRNA expression profiles are altered between health and disease and as such may be considered as biomarkers of disease. Evidence is increasing that miRNAs are particularly important in lung homeostasis and development and have been demonstrated to be the involved in many pulmonary diseases such as asthma, COPD, sarcoidosis, lung cancer and other smoking related diseases. Better understanding of the function of miRNA and the mechanisms underlying their action in the lung, would help to improve current diagnosis and therapeutics strategies in pulmonary diseases. Recently, some miRNA-based drugs have been introduced as possible therapeutic agents. In this review we aim to summarize the recent findings regarding the role of miRNAs in the airways and lung and emphasise their potential therapeutic roles in pulmonary diseases

Exosomes in Severe Asthma: Update in Their Roles and Potential in Therapy

Exosomes are nanosized vesicles and have recently been recognized as important players in cell-to-cell communication. Exosomes contain different mediators such as proteins, nucleic acids (DNA, mRNA, miRNAs, and other ncRNAs), and lipid mediators and can shuttle their exosomal content to both neighboring and distal cells. Exosomes are very effective in orchestrating immune responses in the airways and all cell types can contribute to the systemic exosome pool. Intracellular communication between the broad range of cell types within the lung is crucial in disease emphasizing the importance of exosomes. In asthma, exosomes affect the inflammatory microenvironment which ultimately determines the development or alleviation of the pathological symptoms. Recent studies in this area have provided insight into the underlying mechanisms of disease and led to interest in using exosomes as potential novel therapeutic agents