Additional stories of microRNAs

Saliva as a potential non-invasive liquid biopsy for early and easy diagnosis/prognosis of head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) are the most devastating diseases in India and southeast Asia. It is a preventable and curable disease if detected early. Tobacco and alcohol consumption are the two major risk-factors but infection of high-risk HPVs are also associated with development of predominantly oral and oropharyngeal carcinomas. Interestingly, unlike cervical cancer, HPV-induced HNSCCs show good prognosis and better survival in contrast, majority of tobacco-associated HPV-ve HNSCCs are highly aggressive with poor clinical outcome. Biomarker analysis in circulatory body-fluids for early cancer diagnosis, prognosis and treatment monitoring are becoming important in clinical practice. Early diagnosis using non-invasive saliva for oral or other diseases plays an important role in successful treatment and better prognosis. Saliva mirrors the body's state of health as it comes into direct contact with oral lesions and needs no trained manpower to collect, making it a suitable bio-fluid of choice for screening. Saliva can be used to detect not only virus, bacteria and other biomarkers but variety of molecular and genetic markers for an early detection, treatment and monitoring cancer and other diseases. The performance of saliva-based diagnostics are reported to be highly (≥95 %) sensitive and specific indicating the test's ability to correctly identify true positive or negative cases. This review focuses on the potentials of saliva in the early detection of not only HPV or other pathogens but also identification of highly reliable gene mutations, oral-microbiomes, metabolites, salivary cytokines, non-coding RNAs and exosomal miRNAs. It also discusses the importance of saliva as a reliable, cost-effective and an easy alternative to invasive procedures.

Targeting miRNA by Natural Products: A Novel Therapeutic Approach for Nonalcoholic Fatty Liver

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) as multifactorial chronic liver disease and the lack of a specific treatment have begun a new era in its treatment using gene expression changes and microRNAs. This study aimed to investigate the potential therapeutic effects of natural compounds in NAFLD by regulating miRNA expression. MicroRNAs play essential roles in regulating the cell's biological processes, such as apoptosis, migration, lipid metabolism, insulin resistance, and adipocyte differentiation, by controlling the posttranscriptional gene expression level. The impact of current NAFLD pharmacological management, including drug and biological therapies, is uncertain. In this context, various dietary fruits or medicinal herbal sources have received worldwide attention versus NAFLD development. Natural ingredients such as berberine, lychee pulp, grape seed, and rosemary possess protective and therapeutic effects against NAFLD by modifying the gene's expression and noncoding RNAs, especially miRNAs.

Clusterin and Its Potential Regulatory microRNAs as a Part of Secretome for the Diagnosis of Abnormally Invasive Placenta: Accreta, Increta, and Percreta Cases

Magnetic resonance imaging (MRI) and ultrasound methods used for the diagnosis of an abnormally invasive placenta (AIP) have a wide range of sensitivity (Se, 33–93%) and specificity (Sp, 71–100%) levels, which results in a high risk of unfavorable maternal and perinatal outcomes. The relevance of optimizing the diagnosis of AIP is beyond doubt. Given the epigenetic nature of trophoblast invasion, we aimed to quantitate microRNAs and proteins of their target genes that are potentially associated with AIP in blood plasma samples from 64 pregnant women at gestation weeks 30–34 by reverse transcription coupled with polymerase chain reaction (RT-PCR) and Western blotting, respectively. Statistically significant increases in the expression levels of hsa-miR-17-5p, hsa-miR-21-5p, hsa-miR-25-3p, hsa-miR-92a-3p, and hsa-miR-320a-3p were revealed in the groups of women with AIP (accreta, increta, percreta) relative to the group of women with scars on the uterus or to the group with placenta previa. Opposite changes in the expression level of “gene–target protein/miRNA” pairs were found for the α-subunit of the clusterin secretory form and any of the hsa-miR-21-5p, hsa-miR-25-3p, hsa-miR-92a-3p, hsa-miR-320a-3p, and hsa-miR-17-5p in all cases of AIP. The developed logistic regression models to diagnose AIP cases of various severity gave Se values of 88.8–100% and Sp values of 91.6–100% using a combination of hsa-miR-21-5p, hsa-miR-92a-3p, hsa-miR-320a-3p, or clusterin levels.

Epigenetic Regulation of ALS and CMT: A Lesson from Drosophila Models

Amyotrophic lateral sclerosis (ALS) is the third most common neurodegenerative disorder and is sometimes associated with frontotemporal dementia. Charcot–Marie–Tooth disease (CMT) is one of the most commonly inherited peripheral neuropathies causing the slow progression of sensory and distal muscle defects. Of note, the severity and progression of CMT symptoms markedly vary. The phenotypic heterogeneity of ALS and CMT suggests the existence of modifiers that determine disease characteristics. Epigenetic regulation of biological functions via gene expression without alterations in the DNA sequence may be an important factor. The methylation of DNA, noncoding RNA, and post-translational modification of histones are the major epigenetic mechanisms. Currently, Drosophila is emerging as a useful ALS and CMT model. In this review, we summarize recent studies linking ALS and CMT to epigenetic regulation with a strong emphasis on approaches using Drosophila models.

MiRNA-873-5p Acts as a Potential Novel Biomarker and Promotes Cervical Cancer Progression by Regulating ZEB1 via Notch Signaling Pathway

OBJECTIVE

Our group aimed to investigate the expression pattern of miRNA-873-5p in cervical cancer (CC) patients and its association with CC progression.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was applied for the examination of the expressions of miRNA-873-5p in both CC specimens and cell lines. The clinical significance of miRNA-873-5p was statistically analyzed. MTT, colony formation, Transwell and flow cytometry assays were used to detect cell proliferation, metastasis, and apoptosis changes of Hela and Siha cell line. Luciferase reporter assays and Western blots were utilized to identify the target genes of miRNA-873-5p. Western blot and RT-PCR were used to judge the dysregulation of Notch signaling.

RESULTS

Our results indicated that miRNA-873-5p expression was distinctly reduced in CC patients. Low miRNA-873-5p expressions were distinctly correlated with positively distant metastasis, The International Federation of Gynecology and Obstetrics (FIGO) stage and poor prognosis of CC patients. A functional assay using miRNA-873-5p mimics indicated that overexpression of miRNA-873-5p distinctly suppressed CC cells proliferation and metastasis, and promoted apoptosis. Bioinformatic assays revealed that miRNA-873-5p may target the 3'-UTR of ZEB1 and lead to the suppression of its translation, which was verified by the use of luciferase assays. Finally, overexpression of miRNA-873-5p suppressed the expressions of Jag1, Maml2 and Hey1.

CONCLUSION

Taken together, we firstly provided evidence that miRNA-873-5p expression was a poor favorable factor for CC patients, and the use of miRNA-873-5p may represent a and potential biomarker and promising therapeutic approach for CC.

Regulating Osteogenic Differentiation by Suppression of Exosomal MicroRNAs

IMPACT STATEMENT

We investigated the role of exosomes in osteogenesis and the use of miRNA inhibitor-transfected exosomes to control osteogenic differentiation. RNA-sequencing (RNA-seq) of exosomal miRNAs revealed that growth condition of milieu of preosteoblast exosomes harbors high levels of let-7, which plays a critical role in osteogenesis regulation. We modified exosomes by transfecting let-7 inhibitor into exosomes under growth condition in MC3T3-E1 cells and revealed that exosomes whose let-7 was inactivated by engineering lost the ability to recover osteogenic differentiation. Genetically modified exosomes may serve as powerful biomaterials for developmental control, including of osteogenesis regulation.

Extracellular RNAs in periodontopathogenic outer membrane vesicles promote TNF-α production in human macrophages and cross the blood-brain barrier in mice

Among the main bacteria implicated in the pathology of periodontal disease, Aggregatibacter actinomycetemcomitans (Aa) is well known for causing loss of periodontal attachment and systemic disease. Recent studies have suggested that secreted extracellular RNAs (exRNAs) from several bacteria may be important in periodontitis, although their role is unclear. Emerging evidence indicates that exRNAs circulate in nanosized bilayered and membranous extracellular vesicles (EVs) known as outer membrane vesicles (OMVs) in gram-negative bacteria. In this study, we analyzed the small RNA expression profiles in activated human macrophage-like cells (U937) infected with OMVs from Aa and investigated whether these cells can harbor exRNAs of bacterial origin that have been loaded into the host RNA-induced silencing complex, thus regulating host target transcripts. Our results provide evidence for the cytoplasmic delivery and activity of microbial EV-derived small exRNAs in host gene regulation. The production of TNF-α was promoted by exRNAs via the TLR-8 and NF-κB signaling pathways. Numerous studies have linked periodontal disease to neuroinflammatory diseases but without elucidating specific mechanisms for the connection. We show here that intracardiac injection of Aa OMVs in mice showed successful delivery to the brain after crossing the blood-brain barrier, the exRNA cargos increasing expression of TNF-α in the mouse brain. The current study indicates that host gene regulation by microRNAs originating from OMVs of the periodontal pathogen Aa is a novel mechanism for host gene regulation and that the transfer of OMV exRNAs to the brain may cause neuroinflammatory diseases like Alzheimer's.-Han, E.-C., Choi, S.-Y., Lee, Y., Park, J.-W., Hong, S.-H., Lee, H.-J. Extracellular RNAs in periodontopathogenic outer membrane vesicles promote TNF-α production in human macrophages and cross the blood-brain barrier in mice.

Microbe-Host Communication by Small RNAs in Extracellular Vesicles: Vehicles for Transkingdom RNA Transportation

Extracellular vesicles (EVs) are evolutionary well-conserved nano-sized membranous vesicles that are secreted by both prokaryotic and eukaryotic cells. Recently, they have gained great attention for their proposed roles in cell-to-cell communication, and as biomarkers for human disease. In particular, small RNAs (sRNAs) contained within EVs have been considered as candidate interspecies-communication molecules, due to their demonstrated capacity to modulate gene expression in multiple cell types and species. While research into this field is in its infancy, elucidating the mechanisms that underlie host–microbe interactions and communications promises to impact many fields of biological research, including human health and medicine. Thus, this review discussed the results of recent studies that have examined the ways in which EVs and sRNAs mediate ‘microbe–host’ and ‘host–microbe’ interspecies communication.

Epigenetic mechanisms underlying nervous system diseases

Epigenetic mechanisms act as control systems for modulating genomic structure and activity in response to evolving profiles of cell-extrinsic, cell-cell, and cell-intrinsic signals. These dynamic processes are responsible for mediating cell- and tissue-specific gene expression and function and gene-gene and gene-environmental interactions. The major epigenetic mechanisms include DNA methylation and hydroxymethylation; histone protein posttranslational modifications, nucleosome remodeling/repositioning, and higher-order chromatin reorganization; noncoding RNA regulation; and RNA editing. These mechanisms are intimately involved in executing fundamental genomic programs, including gene transcription, posttranscriptional RNA processing and transport, translation, X-chromosome inactivation, genomic imprinting, retrotransposon regulation, DNA replication, and DNA repair and the maintenance of genomic stability. For the nervous system, epigenetics offers a novel and robust framework for explaining how brain development and aging occur, neural cellular diversity is generated, synaptic and neural network connectivity and plasticity are mediated, and complex cognitive and behavioral phenotypes are inherited transgenerationally. Epigenetic factors and processes are, not surprisingly, implicated in nervous system disease pathophysiology through several emerging paradigms - mutations and genetic variation in genes encoding epigenetic factors; impairments in epigenetic factor expression, localization, and function; epigenetic mechanisms modulating disease-associated factors and pathways; and the presence of deregulated epigenetic profiles in central and peripheral tissues.

Tiny RNAs and their voyage via extracellular vesicles: Secretion of bacterial small RNA and eukaryotic microRNA

MicroRNAs are small non-coding RNAs that bind to the 3'-untranslated region of target mRNAs and have transcriptional or translational inhibitory function in eukaryotes. Before microRNAs were widely known, bacterial non-coding small RNAs around 50-200 nt in length were discovered whose mechanism of action resembled that of microRNAs. Recently, RNAs that are of similar size to or smaller than microRNAs have been discovered in bacteria and indeed, this class of small RNAs have been found throughout all domains of life. Moreover, recent findings suggest that these tiny RNAs can be released via extracellular vesicles (such as exosomes in eukaryotes and outer membrane vesicles in bacteria), which in turn heralds a new field of research, interkingdom communication. This review discusses two similar classes of small RNAs in evolutionarily distinct eukaryotes and bacteria. In addition to their biogenesis and regulation, we discuss small RNA vehicles and their secretion. Impact statement The possible endogenous functions of small RNAs such as regulatory small RNAs in bacteria and microRNAs in eukaryotes have been extensively studied since they were first discovered. However, their powerful functions should not be seen as limited to their cells of origin. Recently, several papers have demonstrated that small RNAs function as signaling molecules between cells. This is possible because small RNAs can be shuttled around after being incorporated into environmentally protective extracellular vesicles. It is now clearly plausible that secreted small RNAs can regulate other types of cells through biofluids. Given their "common molecule" status, the role of small RNAs in mediating bacteria-human crosstalk is an emerging and competitive area of genetic research. This review provides insight into the function of small RNAs in intercellular and even interkingdom communication.

The role of microRNAs in oral lichenoid disorders. Systematic review

Background

Certain changes in the microRNA expression are considered to be associated with chronic inflammatory processes and with the malignant transformation of oral potentially malignant disorders. The purpose of this systematic review is to update the existing data on the aberrant microRNA expression profiles identified in oral lichenoid disease (OLD).

Material and Methods

A search in PubMed-Medline and Scopus was performed on the English literature published between 2010 and August 2016 using the following keywords: oral lichenoid disease, oral lichen planus and microRNA.

Results

Originally, 25 articles were considered, of which 12 case-control articles were selected according to the inclusion/exclusion criteria.

Conclusions

OLD seems to have altered microRNA expression profile. Certain altered microRNAs (146a, 155) may be useful as biomarkers for this disorder. More studies including larger number of cases are needed in order to study further on the biological processes and on the regulation pathways of these altered microRNAs.

Key words:microRNAs, oral lichenoid disease, oral lichen planus.

WITHDRAWN: MicroRNA-505 modulates cancer proliferation and migration in human non-small cell lung cancer through inverse regulation of FZD4

This article has been withdrawn at the request of the Editor-in-Chief. Following peer-review and acceptance of the above referenced paper for publication in Lung Cancer, the Editor-in-Chief was contacted by the Editor-in-Chief of the journal, Gene Therapy, with information that the manuscript had simultaneously been submitted to both Lung Cancer and Gene Therapy. A referee selected to review the manuscript for Gene Therapy was also contacted by the Editor-in-Chief of the journal, Respiratory Research, with a request to review the same manuscript for that journal. The three journals ascertained that the manuscript had been simultaneously submitted to all three journals. In addition, as part of their investigation of potential simultaneous submission, the Editors of Lung Cancer compared the manuscript submitted to Gene Therapy with that accepted for publication in Lung Cancer, and this has raised concerns related to the data presented in the paper. The paper accepted for publication in Lung Cancer examines A549 and H810 cells. The paper submitted to Gene Therapy examines A549 and H510A cells. However, the data presented in both papers, including the figures, are identical. The Editors of Lung Cancer have asked the authors for an explanation, but the corresponding author has not responded. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Oncogene LSD1 is epigenetically suppressed by miR-137 overexpression in human non-small cell lung cancer

PURPOSE

We examined the epigenetic regulation of microRNA-137 (miR-137) on lysine-specific demethylase 1 (KDM1A, or LSD1) induced oncogenic effects in NSCLC.

METHODS

NSCLC cell lines, A549 and H460 cells were transfected with a mammalian LSD1 overexpression plasmid. It's effects on endogenous KDM1A gene and LSD1 protein expressions were examined by qRT-PCR and western blot assays. NSCLC proliferation and migration were also examined by MTT proliferation and wound-scratch assays, respectively. In LSD1-overexpeseed NSCLC cells, lentiviral transfection was conducted to upregulated miR-137 expression. The subsequent effects of miR-137 upregulation on LSD1-mediated cancer regulations were also examined. In addition, key components of histone deacetylases-associated signaling pathways, including EZH2, HDAC1 and HDAC2 were also examined by western blot in LSD1-and miR-137-mediated NSCLC cells.

RESULTS

Mammalian LSD1 overexpression plasmid was efficient in upregulating KDM1A gene and LSD1 protein in A549 and H460 cells. It also exerted oncogenic effects in NSCLC by promoting cancer proliferation and migration. MiR-137 was inversely correlated with LSD1 in NSCLC, as lentivirus-mediated miR-137 upregulation suppressed KDM1A/LSD1 productions and inhibited proliferation or migration in LSD1-overexpressed A549 and H460 cells. Further western blot analysis demonstrated EZH2, HDAC1 and HDAC2 were activated by LSD1, but inhibited by miR-137 in NSCLC.

CONCLUSION

Oncogenic effects of LSD1 were reversely regulated by its upstream epigenetic modulator miR-137 in NSCLC. The interaction between LSD1 and miR-137 may very well involve the regulation on histone deacetylases-associated signaling pathways.

A regulatory BMI1/let-7i/ERK3 pathway controls the motility of head and neck cancer cells

Extracellular signal‐regulated kinase 3 (ERK3) is an atypical mitogen‐activated protein kinase (MAPK), whose biological activity is tightly regulated by its cellular abundance. Recent studies have revealed that ERK3 is upregulated in multiple cancers and promotes cancer cell migration/invasion and drug resistance. Little is known, however, about how ERK3 expression level is upregulated in cancers. Here, we have identified the oncogenic polycomb group protein BMI1 as a positive regulator of ERK3 level in head and neck cancer cells. Mechanistically, BMI1 upregulates ERK3 expression by suppressing the tumor suppressive microRNA (miRNA) let‐7i, which directly targets ERK3 mRNA. ERK3 then acts as an important downstream mediator of BMI1 in promoting cancer cell migration. Importantly, ERK3 protein level is positively correlated with BMI1 level in head and neck tumor specimens of human patients. Taken together, our study revealed a molecular pathway consisting of BMI1, miRNA let‐7i, and ERK3, which controls the migration of head and neck cancer cells, and suggests that ERK3 kinase is a potential new therapeutic target in head and neck cancers, particularly those with BMI1 overexpression.

Secretable Small RNAs via Outer Membrane Vesicles in Periodontal Pathogens

MicroRNAs (miRNAs) have been shown to be major regulators of eukaryotic gene expression. However, bacterial RNAs comparable in size to eukaryotic miRNAs (18-22 nucleotides) have received little attention. Recently, a novel class of small RNAs similar in size to miRNAs (miRNA-size, small RNAs or msRNAs) have also been found in several bacteria. Like miRNAs, msRNAs are approximately 15 to 25 nucleotides in length, and their precursors are predicted to form a hairpin loop secondary structure. Here, we identified msRNAs in the periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola. We examined these msRNAs using a deep sequencing method and characterized dozens of msRNAs through bioinformatic analysis. Highly expressed msRNAs were selected for further validation. The findings suggest that this class of small RNAs is well conserved across the domains of life. Indeed, msRNAs secreted via bacterial outer membrane vesicles (OMVs) were detected. The ability of bacterial OMVs to deliver RNAs into eukaryotic cells was also observed. These msRNAs in OMVs allowed us to identify their potential human immune-related target genes. Furthermore, we found that exogenous msRNAs could suppress expression of certain cytokines in Jurkat T cells. We propose msRNAs may function as novel bacterial signaling molecules that mediate bacteria-to-human interactions. Furthermore, this study may provide fresh insight into bacterial pathogenic mechanisms of periodontal diseases.

Isolation and Characterization of a microRNA-size Secretable Small RNA in Streptococcus sanguinis

MicroRNAs in eukaryotic cells are thought to control highly complex signal transduction and other biological processes by regulating coding transcripts, accounting for their important role in cellular events in eukaryotes. Recently, a novel class of bacterial RNAs similar in size [18-22 nucleotides (nt)] to microRNAs has been reported. Herein, we describe microRNAs, small RNAs from the oral pathogen Streptococcus sanguinis. The bacteria are normally present in the oral cavities and cause endocarditis by contaminating bloodstreams. Small RNAs were analyzed by deep sequencing. Selected highly expressed small RNAs were further validated by real-time polymerase chain reaction and northern blot analyses. We found that skim milk supplement changed the expression of small RNAs S.S-1964 in tandem with the nearby SSA_0513 gene involved in vitamin B₁₂ conversion. We furthermore observed small RNAs secreted via bacterial membrane vesicles. Although their precise function remains unclear, secretable small RNAs may represent an entirely new area of study in bacterial genetics.

MicroRNAs in the Evaluation and Potential Treatment of Liver Diseases

Acute and chronic liver disease continue to result in significant morbidity and mortality of patients, along with increasing burden on their families, society and the health care system. This in part is due to increased incidence of liver disease associated factors such as metabolic syndrome; improved survival of patients with chronic predisposing conditions such as HIV; as well as advances in the field of transplantation and associated care leading to improved survival. The fact that one disease can result in different manifestations and outcomes highlights the need for improved understanding of not just genetic phenomenon predisposing to a condition, but additionally the role of epigenetic and environmental factors leading to the phenotype of the disease. It is not surprising that providers continue to face daily challenges pertaining to diagnostic accuracy, prognostication of disease severity, progression, and response to therapies. A number of these challenges can be addressed by incorporating a personalized approach of management to the current paradigm of care. Recent advances in the fields of molecular biology and genetics have paved the way to more accurate, individualized and precise approach to caring for liver disease. The study of microRNAs and their role in both healthy and diseased livers is one example of such advances. As these small, non-coding RNAs work on fine-tuning of cellular activities and organ function in a dynamic and precise fashion, they provide us a golden opportunity to advance the field of hepatology. The study of microRNAs in liver disease promises tremendous improvement in hepatology and is likely to lay the foundation towards a personalized approach in liver disease.

A circulating non-coding RNA panel as an early detection predictor of non-small cell lung cancer

AIMS

Early non-small cell lung cancer (NSCLC) diagnosis is generally poor due to the lack of convenient and noninvasive tools. MicroRNAs (miRNAs) and the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) are non-coding RNAs, that have attracted increased attention for their use as NSCLC tumor diagnostic markers.

MAIN METHODS

We constructed a serum miRNA and MALAT1 non-coding RNA panel and tested its diagnostic performance as an NSCLC biomarker. We tested the expression of 11 candidate miRNAs and MALAT1 in a training set (36 NSCLCs vs. 36 controls) by quantitative reverse transcription polymerase chain reactions. The serum non-coding RNA panel's diagnostic efficiency was tested and validated in a second validation sample set (120 NSCLCs and 71 controls) by receiver operating characteristic (ROC) curve analyses.

KEY FINDINGS

In the training set, the expression of the four non-coding RNAs (miR-1254, miR-485-5p, miR-574-5p, and MALAT1) was obviously different between the NSCLC patients and healthy controls. Risk score analysis revealed that the four non-coding RNA panel can distinguish NSCLC patient samples from controls. The ROC curve results revealed areas under the curves (AUCs) of 0.861 (95% confidence interval (CI) 0.771-0.952) and 0.844 (95% CI0.778-0.910) for the training set and validation set, respectively.

SIGNIFICANCE

The four non-coding RNA risk scores were also associated with NSCLC progression, and its diagnostic efficiency was relatively high for stages I/II/III. In conclusion, these data indicate that the four non-coding RNA panel can serve as a convenient tool for early NSCLC diagnosis.

MicroRNAs in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disorder. Strongly linked to obesity and diabetes, NAFLD has the characteristics of complex diseases with substantial heterogeneity. Accordingly, our ability to predict the risk of advanced NAFLD and provide efficient treatment may improve by a better understanding of the relationship between genotype and phenotype. MicroRNAs (miRNAs) play a major role in the fine-tuning of gene expression and they have recently emerged as novel biomarkers and therapeutic tools in the management of NAFLD. These short non-coding RNA sequences act by partial repression or degradation of targeted mRNAs. Deregulation of miRNAs has been associated with different stages of NAFLD, while their biological role in the pathogenesis remains to be fully understood. Systems biology analyses based on predicted target genes have associated hepatic miRNAs with molecular pathways involved in NAFLD progression such as cholesterol and lipid metabolism, insulin signaling, oxidative stress, inflammation, and pathways of cell survival and proliferation. Moreover, circulating miRNAs have been identified as promising noninvasive biomarkers of NAFLD and linked to disease severity. This rapidly growing field is likely to result in major advances in the pathomechanism, prognostication, and treatment of NAFLD.

Diagnostic profiling of salivary exosomal microRNAs in oral lichen planus patients

OBJECTIVE

Oral lichen planus is a chronic inflammatory oral mucosal disease whose exact cause is unclear and which requires efficient diagnostic and therapeutic strategies. Identification of disease-specific biomarkers in saliva is an easy, quick, and non-invasive approach for molecular diagnosis. This study was designed to examine salivary exosomal microRNAs (miRNAs) that could be candidates for diagnosing and elucidating the pathogenesis of oral lichen planus.

SUBJECTS AND METHODS

We compared miRNA profiles of salivary exosomes of patients with oral lichen planus with those of healthy controls. Saliva samples from 16 patients with oral lichen planus and eight healthy controls were divided into two sets and examined using miRNA microarray analysis and TaqMan quantitative PCR.

RESULTS

The three miRNAs identified (miR-4484, miR-1246, and miR-1290) were further validated. Of these, miR-4484 was significantly upregulated in the salivary exosomes of patients with oral lichen planus.

CONCLUSIONS

This study thus identifies a potential miRNA biomarker for oral lichen planus and provides insight into the functions of miRNAs in the pathogenesis of oral inflammatory diseases.

Revisiting Chaos Theorem to Understand the Nature of miRNAs in Response to Drugs of Abuse

Just like Matryoshka dolls, biological systems follow a hierarchical order that is based on dynamic bidirectional communication among its components. In addition to the convoluted inter-relationships, the complexity of each component spans several folds. Therefore, it becomes rather challenging to investigate phenotypes resulting from these networks as it requires the integration of reductionistic and holistic approaches. One dynamic system is the transcriptome which comprises a variety of RNA species. Some, like microRNAs, have recently received a lot of attention. miRNAs are very pleiotropic and have been considered as therapeutic and diagnostic candidates in the biomedical fields. In this review, we survey miRNA profiles in response to drugs of abuse (DA) using 118 studies. After providing a summary of miRNAs related to substance use disorders (SUD), general patterns of miRNA signatures are compared among studies for single or multiple drugs of abuse. Then, current challenges and drawbacks in the field are discussed. Finally, we provide support for considering miRNAs as a chaotic system in normal versus disrupted states particularly in SUD and propose an integrative approach for studying and analyzing miRNA data.