Small RNAs have a large impact: circulating microRNAs as biomarkers for human diseases

One-Step Monitoring of Multiple Enterovirus 71 Infection-Related MicroRNAs Using Core-Satellite Structure of Magnetic Nanobeads and Multicolor Quantum Dots

The accurate and rapid monitoring of the expression levels of enterovirus 71 (EV71)-related microRNAs (miRNAs) can contribute to diagnosis of hand, foot, and mouth disease (HFMD) at the early stage. However, there is currently a lack of convenient methods for simultaneous monitoring of multiplex miRNAs in one step. Herein a one-step method for the simultaneous monitoring of multiple EV71 infection-related miRNAs is developed based on core-satellite structure assembled with magnetic nanobeads and quantum dots (MNs-ssDNA-QDs). In the presence of target miRNAs, duplex-specific nuclease (DSN)-assisted target recycling can be triggered, resulting in the release of QDs and recycling of target miRNAs. Then the simultaneous quantification can be easily realized by recording the corresponding amplified fluorescence signal of QDs in the suspension. With this method, simultaneous detection of hsa-miRNA-296-5p and hsa-miRNA-16-5p, potential biomarkers of EV71 infection, can be easily achieved with femtomolar sensitivity and single-base mismatch specificity. Moreover, the method is successfully used for monitoring of the expression level of miRNAs in EV71-infected cells at different time points, demonstrating the potential for diagnostic applications. With the merits of one-step operation and single-nucleotide mismatch discrimination, this work opens a new avenue for multiplex miRNAs detection. As different nucleotide sequences and multicolor QDs can be employed, this work is expected to offer great potential for the development of high throughput diagnosis.

Oxidative stress and antioxidants in the trabecular meshwork

Glaucoma is an age-dependent disease closely related to oxidative stress and is regarded as the second leading cause of irreversible blindness worldwide. In recent years, many studies have shown that morphological and functional abnormalities of the trabecular meshwork (TM) are closely related to glaucoma, especially with respect to oxidative stress. In this review, the mechanisms of oxidative stress in the TM and treatment strategies for this condition, including strategies involving antioxidants, noncoding RNAs and exogenous compounds, are discussed. Although many questions remain to be answered, the reviewed findings provide insights for further research on oxidative stress alleviation in glaucoma and suggest new targets for glaucoma prevention.

Identification of suitable controls for miRNA quantification in T-cells and whole blood cells in sepsis

Complex immune dysregulation is a hallmark of sepsis. The occurring phases of immunosuppression and hyperinflammation require rapid detection and close monitoring. Reliable tools to monitor patient’s immune status are yet missing. Currently, microRNAs are being discussed as promising new biomarkers in sepsis. However, no suitable internal control for normalization of miRNA expression by qPCR has been validated so far, thus hampering their potential benefit. We here present the first evaluation of endogenous controls for miRNA analysis in human sepsis. Novel candidate reference miRNAs were identified via miRNA microArray. TaqMan qPCR assays were performed to evaluate these microRNAs in T-cells and whole blood cells of sepsis patients and healthy controls in two independent cohorts. In T-cells, U48 and miR-320 proved suitable as endogenous controls, while in whole blood cells, U44 and miR-942 provided best stability values for normalization of miRNA quantification. Commonly used snRNA U6 exhibited worst stability in all sample groups. The identified internal controls have been prospectively validated in independent cohorts. The critical importance of housekeeping gene selection is emphasized by exemplary quantification of imuno-miR-150 in sepsis patients. Use of appropriate internal controls could facilitate research on miRNA-based biomarker-use and might even improve treatment strategies in the future.

Circulating Plasma microRNAs are Altered with Amyloidosis in a Mouse Model of Alzheimer's Disease

Pathological changes underlying Alzheimer's disease (AD) begin decades before the classical symptoms of memory loss become evident. As microRNAs are released from neurons and enter the bloodstream, circulating microRNAs may be reflective of AD progression and are ideal candidates as biomarkers for early-stage disease detection. Here, we provide a novel, in-depth analysis of how plasma microRNAs alter with aging, the most prominent risk factor for AD, and with development of amyloid-β (Aβ) plaque deposition. We assessed the circulating microRNAs in APPswe/PSEN1dE9 transgenic mice and wild-type controls at 4, 8 and 15 m (n = 8-10) using custom designed Taqman arrays representing 185 neuropathology-related microRNAs. We performed a linear mixed-effects model to investigate the effects of age and genotype on plasma microRNAs expression. Following this analysis, we found 8 microRNAs were significantly affected by age alone in wild-type animals and 12 microRNAs altered in APPswe/PSEN1dE9 mice, either prior to Aβ plaque deposition (4 m) or during the development of AD-like pathogenesis (8 m or 15 m). Importantly, we found that differing sets of microRNAs were identified at each time point. Functional analysis of these data revealed that while common biological pathways, such as Inflammatory Response, were enriched throughout the disease process, Free Radical Scavenging, Immunological Disease, and Apoptosis Signaling were specifically enriched later in the disease process. Overall, this study reinforces that distinct biological processes underpin the early versus late stages of AD-like pathogenesis and highlights potential pre-symptomatic microRNAs biomarkers of neurodegeneration.

New insights into the genetics and epigenetics of systemic sclerosis

Systemic sclerosis (SSc) is a severe autoimmune disease that is characterized by vascular abnormalities, immunological alterations and fibrosis of the skin and internal organs. The results of genetic studies in patients with SSc have revealed statistically significant genetic associations with disease manifestations and progression. Nevertheless, genetic susceptibility to SSc is moderate, and the functional consequences of genetic associations remain only partially characterized. A current hypothesis is that, in genetically susceptible individuals, epigenetic modifications constitute the driving force for disease initiation. As epigenetic alterations can occur years before fibrosis appears, these changes could represent a potential link between inflammation and tissue fibrosis. Epigenetics is a fast-growing discipline, and a considerable number of important epigenetic studies in SSc have been published in the past few years that span histone post-translational modifications, DNA methylation, microRNAs and long non-coding RNAs. This Review describes the latest insights into genetic and epigenetic contributions to the pathogenesis of SSc and aims to provide an improved understanding of the molecular pathways that link inflammation and fibrosis. This knowledge will be of paramount importance for the development of medicines that are effective in treating or even reversing tissue fibrosis.

Circulating miRNAs as Novel Diagnostic Biomarkers in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

Recent studies have indicated that circulating miRNAs could serve as accurate biomarkers for diagnosing nonalcoholic fatty liver disease (NAFLD). We aimed to assess the evidence on the probability of circulating miRNAs as new diagnostic biomarkers in patients with NAFLD.

METHODS

We comprehensively retrieved relevant English literature from the databases of PubMed, Embase, and the Cochrane Library from 2000 to 1 January 2019. The diagnostic accuracy of circulating miRNAs as markers for NAFLD was analyzed. Moreover, we evaluated the methodological quality of the included article. STATA was applied to perform statistical analyses.

RESULTS

In this meta-analysis, 17 studies that enrolled 1408 patients of NAFLD and 926 healthy people from 6 articles were analyzed. We constructed a summary receiver-operating characteristic (SROC) curve of all circulating miRNAs, and the area under the curve (AUC) was 0.83, with the pooled sensitivity (SEN) 0.70 and the pooled specificity (SPE) 0.82 in distinguishing patients with NAFLD from healthy controls. Among them, miR-122 showed high diagnostic accuracy, with the diagnostic index of pooled SEN, SPE, and AUC being 0.88, 0.66, and 0.86, respectively. We then performed subgroup analyses based on the mode of miRNA regulation, countries, miRNA profiling, sample size, and male proportion. We then did a regression analysis and found the cause of heterogeneity might be miRNA profiling. Finally, publication bias was not found, and Fagan's nomogram showed valuable clinical utility.

CONCLUSION

Circulating miRNAs, especially miR-122, might be promising diagnostic biomarkers for NAFLD with high-accuracy, and more large-sample studies are required to support the above findings in the future.

Expression of MicroRNAs miR-145, miR-181c, miR-199a and miR-1183 in the Blood and Hippocampus of Patients with Mesial Temporal Lobe Epilepsy

The aim of this study was to analyze the expression profiles of the microRNAs (miRNAs) miR-145, miR-181c, miR-199a and miR-1183 in the hippocampus and blood of patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and to investigate whether these can be used as diagnosis and prognosis biomarkers for epilepsy. Hippocampus and blood samples were collected from 20 patients with MTLE-HS, ten of whom had a favorable surgical outcome (Engel I) and ten with an unfavorable surgical outcome (Engel III-IV). Hippocampus samples from autopsied individuals with no neurological or psychiatric medical history (necropsy samples) and blood samples from healthy individuals were used as controls. Real-time quantitative PCR (RQ-PCR) was used to analyze miRNA expression. The results showed that the expressions of these miRNAs differed quantitatively in the hippocampus and blood of patients with MTLE-HS in comparison to the respective control. This difference was most pronounced for miR-145, which was hypo-expressed in the hippocampus and hyper-expressed in the blood of MTLE-HS patients. MiRNAs miR-145, miR-181c, miR-199a and miR-1183 were hyper-expressed in the blood of patients with MTLE-HS. No statistical differences in the levels of these miRNAs in the blood or hippocampus were found between Engel I patients and Engel III-IV patients. These results suggest that the analyzed microRNAs are potential circulating biomarkers for epilepsy diagnosis.

Electrochemical-based biosensors for microRNA detection: Nanotechnology comes into view

Nanotechnology plays an undeniable significant role in medical sciences, particularly in the field of biomedicine. Development of several diagnostic procedures in medicine has been possible through the beneficial application of nano-materials, among which electrochemical nano-biosensors can be mentioned. They can be employed to quantify various clinical biomarkers in detection, evaluation, and follow up stages of the illnesses. MicroRNAs, a group of regulatory short RNA fragments, added a new dimension to the management and diagnosis of several diseases. Mature miRNAs are single-stranded RNA molecules approximately 22 nucleotides in length, which regulate a vast range of biological functions from cellular proliferation and death to cancer development and progression. Recently, diagnostic value of miRNAs in various diseases has been demonstrated. There are many traditional methods for detection of miRNAs including northern blotting, quantitative real time PCR (qRT-PCR), microarray technology, nanotechnology-based approaches, and molecular biology tools including miRNA biosensors. In comparison with other techniques, electrochemical nucleic acid biosensor methods exhibit many interesting features, and could play an important role in the future nucleic acid analysis. This review paper provides an overview of some different types of nanotechnology-based biosensors for detection of miRNAs.

Identification of Candidate miRNA Biomarkers for Glaucoma

Purpose

Glaucoma, a leading cause of blindness worldwide, often remains undetected until irreversible vision loss has occurred. Treatments focus on lowering intraocular pressure (IOP), the only modifiable and readily measurable risk factor. However, IOP can vary and does not always predict disease progression. MicroRNAs (miRNAs) are promising biomarkers. They are abundant and stable in biological fluids, including plasma and aqueous humor (AqH). We aimed to identify differentially expressed miRNAs in AqH and plasma from glaucoma, exfoliation syndrome (XFS), and control subjects.

Methods

Plasma and AqH from two ethnic cohorts were harvested from glaucoma or XFS (often associated with glaucoma, n = 33) and control (n = 31) patients undergoing elective surgery. A custom miRNA array measured 372 miRNAs. Molecular target prediction and pathway analysis were performed with Ingenuity Pathway Analysis (IPA) and DIANA bioinformatical tools.

Results

Levels of miRNAs in plasma, a readily accessible biomarker source, correlated with miRNA levels in AqH. Twenty circulating miRNAs were at least 1.5-fold higher in glaucoma or XFS patients than in controls across two ethnic cohorts: miR-4667-5p (P = 4.1 × 10⁻⁵), miR-99b-3p (P = 4.8 × 10⁻⁵), miR-637 (P = 5.1 × 10⁻⁵), miR-4490 (P = 5.7 × 10⁻⁵), miR-1253 (P = 6.0 × 10⁻⁵), miR-3190-3p (P = 3.1 × 10⁻⁴), miR-3173-3p (P = 0.001), miR-608 (P = 0.001), miR-4725-3p (P = 0.002), miR-4448 (P = 0.002), and miR-323b-5p (P = 0.002), miR-4538 (P = 0.003), miR-3913-3p (P = 0.003), miR-3159 (P = 0.003), miR-4663 (P = 0.003), miR-4767 (P = 0.003), miR-4724-5p (P = 0.003), miR-1306-5p (P = 0.003), miR-181b-3p (P = 0.004), and miR-433-3p (P = 0.004). miR-637, miR-1306-5p, and miR-3159, in combination, allowed discrimination between glaucoma patients and control subjects (AUC = 0.91 ± 0.008, sensitivity 85.0%, specificity 87.5%).

Conclusions

These results identify specific miRNAs as potential biomarkers and provide insight into the molecular processes underlying glaucoma.

MicroRNA profiling of plasma exosomes from patients with ovarian cancer using high-throughput sequencing

To the best of our knowledge, the microRNA (miR/miRNA) expression profile of plasma exosomes in ovarian cancer has not been previously studied. The aim of the present study was to investigate the practicality of using plasma exosomal miRNAs as novel serological biomarkers of ovarian cancer. In the study, exosome-like vesicles were purified from the plasma of patients with ovarian cancer and healthy women using differential centrifugation. The purified vesicles, ranging from 50-100 nm in size, were identified as exosomes by transmission electron microscopy and western blotting. High-throughput sequencing demonstrated that 65 known miRNAs, 34 of which were upregulated and 31 downregulated, were differentially expressed between patients with ovarian cancer and healthy women (P<0.05; fold change ≥2). The miRNA expression levels of hsa-miR-106a-5p, hsa-let-7d-5p and hsa-miR-93-5p were significantly increased, whereas hsa-miR-122-5p, hsa-miR-185-5p and hsa-miR-99b-5p expression levels were significantly decreased in the exosomes of patients with ovarian cancer compared with those in the healthy controls. Additionally, the miRNA expression levels of plasma hsa-miR-93-5p were significantly increased in patients with ovarian cancer compared with those in the healthy controls, while the plasma expression levels of hsa-miR-122-5p and hsa-miR-99b-5p were significantly decreased in patients with ovarian cancer compared with those in the healthy controls. Overall, the present study identified plasma and exosomal miRNAs with dysregulated expression in patients with ovarian cancer compared with that in healthy controls, and the differentially expressed miRNAs may have potential as diagnostic and prognostic targets for the treatment of patients with ovarian cancer.

Crucial Role of Extracellular Vesicles in Bronchial Asthma

Extracellular vesicles (EVs) are circulating vesicles secreted by various cell types. EVs are classified into three groups according to size, structural components, and generation process of vesicles: exosomes, microvesicles, and apoptotic bodies. Recently, EVs have been considered to be crucial for cell-to-cell communications and homeostasis because they contain intracellular proteins and nucleic acids. Epithelial cells from mice suffering from bronchial asthma (BA) secrete more EVs and suppress inflammation-induced EV production. Moreover, microarray analyses of bronchoalveolar lavage fluid have revealed that several microRNAs are useful novel biomarkers of BA. Mesenchymal stromal cell-derived EVs are possible candidates of novel BA therapy. In this review, we highlight the biologic roles of EVs in BA and review novel EV-targeted therapy to help understanding by clinicians and biologists.

Dual Laplacian regularized matrix completion for microRNA-disease associations prediction

Since lots of miRNA-disease associations have been verified, it is meaningful to discover more miRNA-disease associations for serving disease diagnosis and prevention of human complex diseases. However, it is not practical to identify potential associations using traditional biological experimental methods since the process is expensive and time consuming. Therefore, it is necessary to develop efficient computational methods to accomplish this task. In this work, we introduced a matrix completion model with dual Laplacian regularization (DLRMC) to infer unknown miRNA-disease associations in heterogeneous omics data. Specifically, DLRMC transformed the task of miRNA-disease association prediction into a matrix completion problem, in which the potential missing entries of the miRNA-disease association matrix were calculated, the missing association can be obtained based on the prediction scores after the completion procedure. Meanwhile, the miRNA functional similarity and the disease semantic similarity were fully exploited to serve the miRNA-disease association matrix completion by using a dual Laplacian regularization term. In the experiments, we conducted global and local Leave-One-Out Cross Validation (LOOCV) and case studies to evaluate the efficacy of DLRMC on the Human miRNA-disease associations dataset obtained from the HMDDv2.0 database. As a result, the AUCs of DLRMC is 0.9174 and 0.8289 in global LOOCV and local LOOCV, respectively, which significantly outperform a variety of previous methods. In addition, in the case studies on four significant diseases related to human health including Colon Neoplasms, Kidney neoplasms, Lymphoma and Prostate neoplasms, 90%, 92%, 92% and 94% out of the top 50 predicted miRNAs has been confirmed, respectively.

Circulating miR-29b positively correlates with non-alcoholic fatty liver disease in a Chinese population

OBJECTIVE

Early screening of non-alcoholic fatty liver disease (NAFLD) is of great significance for the early detection and intervention in NAFLD. MicroRNAs (miRNAs) are important regulators of metabolic diseases including NAFLD. The aim of this study was to investigate the association of serum miR-29a-c with NAFLD in a Chinese population.

METHODS

Participants were divided into four groups based on the presence or absence of NAFLD and/or type 2 diabetes mellitus (T2DM). Quantitative polymerase chain reaction analysis was performed to quantify serum level of miR-29a-c. The association of miR-29a-c with NAFLD was evaluated.

RESULTS

Serum miR-29b, but not miR-29a or miR-29c, was positively associated with NAFLD (odds ratio [OR] 2.04 [1.16- 3.58], P = 0.013). Additionally, age, serum triglyceride and fasting plasma glucose (FPG) levels were independently associated with miR-29b (β ± standard error [SE] = 0.004 ± 0.002, P = 0.019 for age; β ± SE = 0.110 ± 0.054, P = 0.042 for triglyceride; and β ± SE = 0.389 ± 0.161, P = 0.016 for FPG). MiR-29b level was positively correlated with intrahepatic lipid content (β ± SE = 6.055 ± 2.630, P = 0.024) after adjusted for age, sex, and body mass index.

CONCLUSIONS

Serum miR-29b was associated with intrahepatic lipid content and NAFLD in a Chinese population-based study.

MicroRNAs and Long Non-coding RNAs in Genetic Diseases

Since the discovery and classification of non-coding RNAs, their roles have gained great attention. In this respect, microRNAs and long non-coding RNAs have been firmly demonstrated to be linked to regulation of gene expression and onset of human diseases, including rare genetic diseases; therefore they are suitable targets for therapeutic intervention. This issue, in the context of rare genetic diseases, is being considered by an increasing number of research groups and is of key interest to the health community. In the case of rare genetic diseases, the possibility of developing personalized therapy in precision medicine has attracted the attention of researchers and clinicians involved in developing "orphan medicinal products" and proposing these to the European Medicines Agency (EMA) and to the Food and Drug Administration (FDA) Office of Orphan Products Development (OOPD) in the United States. The major focuses of these activities are the evaluation and development of products (drugs, biologics, devices, or medical foods) considered to be promising for diagnosis and/or treatment of rare diseases or conditions, including rare genetic diseases. In an increasing number of rare genetic diseases, analysis of microRNAs and long non-coding RNAs has been proven a promising strategy. These diseases include, but are not limited to, Duchenne muscular dystrophy, cystic fibrosis, Rett syndrome, and β-thalassemia. In conclusion, a large number of approaches based on targeting microRNAs and long non-coding RNAs are expected in the field of molecular diagnosis and therapy, with a facilitated technological transfer in the case of rare genetic diseases, in virtue of the existing regulation concerning these diseases.

miR-543 inhibites cervical cancer growth and metastasis by targeting TRPM7

Dysregulation of miR-543 has been implicated to play crucial roles in various human cancers. However, the function of miR-543 involved in cervical cancer (CC) progress remains largely unknown. Thus, this study aimed to explore the potential role of miR-543 and the underlying mechanisms in human CC. In this study, we found that miR-543 was significantly downregulated in 69 CC tissue samples and cell lines when compared to adjacent normal tissues and cell line. Decreased miR-543 was closely correlated with poor clinicopathological parameters including larger tumor size, late FIGO stage and lymph node metastasis. Overexpression of miR-543 in CC cell lines remarkably inhibited cell proliferation, invasion and migration, caused cell cycle arrest, promoted apoptosis in vitro, and suppressed tumor growth in vivo, whereas miR-543 inhibitor showed the opposite effect. Dual-luciferase assay validated that 3'-untranslated region (UTR) of transient receptor potential melastatin 7 (TRPM7) was a direct binding site of miR-543. Rescue experiments showed that restoration of TRPM7 expression partially reversed the miR-543-mediated inhibition of proliferation and invasion in CC cells. Further studies confirmed that P13K/AKT and p38/MAPK signaling was involved in miR-543/TRPM7 axis mediated CC progression. Thus, these findings demonstrated the tumor suppressor role of miR-543 on CC progression, which might serve as a potential biomarker for CC diagnosis and therapy.

Circulating microRNAs in patients with immune thrombocytopenia before and after treatment with thrombopoietin-receptor agonists

MicroRNAs (miRNAs) are small non-coding RNAs involved in the regulation of gene expression. Dysregulated expression of several miRNAs has been found in primary immune thrombocytopenia (ITP) suggesting that miRNAs are likely involved in the pathogenesis of ITP. We aimed to explore the differential expression of miRNAs in patients with ITP before and after starting treatment with thrombopoietin-receptor agonists (TPO-RAs) to clarify their roles in the pathophysiology of ITP, and as potential diagnostic and prognostic markers of this disorder.We performed a profiling study where 179 miRNAs were analyzed in eight ITP patients before and during treatment with TPO-RAs and in eight controls using miRNA PCR panel; 81 miRNAs were differentially expressed in ITP patients compared to controls, and 14 miRNAs showed significant changes during TPO-RA-treatment. Ten miRNAs were selected for validation that was performed in 23 patients and 22 controls using droplet digital PCR. Three miRNAs were found to be differentially expressed in ITP patients before TPO-RA-treatment compared to controls: miR-199a-5p was down-regulated (p = 0.0001), miR-33a-5p (p = 0.0002) and miR-195-5p (p = 0.035) were up-regulated. Treatment with TPO-RAs resulted in changes in six miRNAs including miR-199a-5p (p = 0.001), miR-33a-5p (p = 0.003), miR-382-5p (p = 0.004), miR-92b-3p (p = 0.005), miR-26a-5p (p = 0.008) and miR-221-3p (p = 0.023); while miR-195-5p remained unchanged and significantly higher than in controls, despite the increase in the platelet count, which may indicate its possible role in the pathophysiology of ITP. Regression analysis revealed that pre-treatment levels of miR-199a-5p and miR-221-3p could help to predict platelet response to TPO-RA-treatment. ROC curve analysis showed that the combination of miR-199a-5p and miR-33a-5p could distinguish patients with ITP from controls with AUC of 0.93.This study identifies a number of differentially expressed miRNAs in ITP patients before and after initiation of TPO-RAs with potential roles in the pathophysiology, as well as with a possible utility as diagnostic and prognostic biomarkers. These interesting findings deserve further exploration and validation in future studies.

Circulating microRNA-155 is associated with insulin resistance in chronic hepatitis C patients

BACKGROUND AND STUDY AIM

Hepatitis C represents a potential public health problem worldwide. Insulin resistance (IR) and type 2 diabetes (T2D) are among the serious metabolic complications for chronic hepatitis C virus (HCV) infection. MicroRNAs (miRNAs) are a group of small non-coding RNAs which are implicated in the modulation of almost all biological processes. The objective of this study was to investigate the levels of both miR-155 and miR-34a in sera of chronic HCV patients with or without T2D.

PATIENTS AND METHODS

In this study, we investigated the expression of both miR-155 and miR-34a in 80 subjects (20 HCV, 19 HCV/T2D, 21 T2D and 19 healthy controls), using quantitative real-time PCR.

RESULTS

Our results revealed significantly higher levels of both miR-155 and miR-34a in chronic HCV patients compared to healthy control subjects. However, only circulating miR-155 levels showed significant decline in diabetic HCV patients compared to non-diabetic HCV group. Intriguingly, the circulating levels of miR-155 were inversely correlated with HOMA-IR, fasting blood glucose and HbA1c levels.

CONCLUSION

Our findings indicate that the insulin resistance and T2D in HCV are strongly related to miR-155. This may suggest a role for miR-155 in the pathogenesis of IR caused by HCV. However, further large-scale studies are required to confirm our findings.

Circulating microRNA146b-5p is superior to C-reactive protein as a novel biomarker for monitoring inflammatory bowel disease

BACKGROUND

Owing to the importance of early treatment, simple and reliable methods for monitoring inflammatory bowel disease (IBD) are needed.

AIMS

To determine whether circulating microRNAs are reliable biomarkers for IBD monitoring.

METHODS

Serum levels of 17 candidate microRNAs were measured by quantitative real-time polymerase chain reaction in a discovery cohort (n = 120). Differentially expressed serum microRNAs were further investigated in an independent training cohort (n = 341). Correlations between relative microRNA levels and disease activity were evaluated. A disease control group was included to investigate the specificity of microRNA. Logistical regression was used to construct a microRNA classifier to identify endoscopic activity. Its predictive value was explored in the validation cohort (n = 66) using the area under the receiver operating characteristic curve (AUC).

RESULTS

Serum microRNA146b-5p (miR-146b-5p) expression was 2.87- and 2.72-fold higher in patients with Crohn's disease and ulcerative colitis, respectively, than in healthy controls. Serum miR-146b-5p was significantly correlated with disease activity and was more specific than C-reactive protein (CRP). A classifier was built for Crohn's disease, ie P [Endoscopically active] = 11+e2.937-0.737(miR-146b-5p)-0.008PLT , with a greater AUC of 0.869 [0.764-0.940] than that for CRP (0.680 [0.554-0.790]) (P = 0.0043).

CONCLUSIONS

MiR-146b-5p may better reflect mucosal inflammation in IBD than CRP. The Crohn's disease classifier developed in this study may be valuable for identifying endoscopic activity in patients with Crohn's disease.

Multiple epigenetic biomarkers for evaluation of students' academic performance

Several reports have shown that methyl CpG-binding protein 2 (MeCP2), brain-derived neurotrophic factor (BDNF), phospho-cAMP response element-binding protein (p-CREB) and microRNAs may be important in regulating academic performance because of their roles in neuropsychiatry and cognitive diseases. The first goal of this study was to explore the associations among MeCP2, BDNF, CREB and academic performance. This study also examined the pathway responsible for the effects of MeCP2, BDNF, p-CREB and microRNAs on academic performance. Scores from the basic competency test, an annual national competitive entrance examination, were used to evaluate academic performance. Subjects' plasma RNA was extracted and analyzed. This study determined that participants in the higher academic performance group had a significant difference in MECP2 mRNA expression compared with the lower academic performance group. We then used neuronal human derived neuroblastoma cell line (SH-SY5Y) cells with inducible MeCP2 expression from a second copy of the gene as a gain-of-function model and found that MeCP2 overexpression positively affected p-CREB and BDNF expression initially. After negative feedback, the p-CREB and BDNF levels subsequently decreased. In the neuronal phenotype examination, we found a significant reduction in total outgrowth and branches in MeCP2-induced cells compared with noninduced cells. This work describes pathways that may be responsible for the effects of MeCP2, BDNF, p-CREB and microRNAs on academic performance. These results may shed light on the development of promising clinical treatment strategies in the area of neuropsychological adjustment.

MicroRNA-411 Inhibits Cervical Cancer Progression by Directly Targeting STAT3

Cervical cancer is the third most common gynecological cancer and the fourth leading cause of cancer-related deaths in women around the world. Substantial evidence has demonstrated that microRNA (miRNA) expression is disordered in many malignant tumors. The dysregulation of miRNAs has been suggested to be involved in the tumorigenesis and tumor development of cervical cancer. Therefore, identification of miRNAs and their biological roles and targets involved in tumor pathology would provide valuable insight into the diagnosis and treatment of patients with cervical cancer. MicroRNA-411 (miR-411) has been reported to play an important role in several types of human cancer. However, the expression level, role, and underlying molecular mechanisms of miR-411 in cervical cancer remain unclear. Therefore, the objectives of this study were to investigate the expression pattern and clinical significance of miR-411 in cervical cancer and to evaluate its role and underlying mechanisms in this disease. In this study, we confirmed that the expression of miR-411 was significantly downregulated in both cervical cancer tissues and cell lines. Low expression of miR-411 was associated with tumor size, FIGO stage, lymph node metastasis, and distant metastasis. Additionally, miR-411 overexpression inhibited cell proliferation and invasion in cervical cancer. Furthermore, signal transducer and activator of transcription 3 (STAT3) was identified as a direct target of miR-411 in this disease. In clinical samples, miR-411 expression levels were inversely correlated with STAT3, which was significantly upregulated in cervical cancer. Restored STAT3 expression abolished the tumor-suppressing effects of miR-411 overexpression on the proliferation and invasion of cervical cancer cells. In conclusion, our data demonstrated that miR-411 inhibited cervical cancer progression by directly targeting STAT3 and may represent a novel potential therapeutic target and prognostic marker for patients with this disease.

Social Isolation Rearing Induces Neuropsychiatric Diseases: Updated Overview

Neuropsychiatric and neurologic diseases cause a great burden for individuals, families, and societies. Social isolation rearing can trigger a variety of psychiatric diseases. New advances suggest that epigenetic factors along with other neurochemical changes can be an important topic in neuropsychiatric diseases. It is thought that the prevention of social isolation rearing that occurs around birth can reduce the occurrence of neuropsychiatric diseases. It has been suggested that the environment can induce epigenetic alternation. So, for the diagnosis of a proportion of neuropsychiatric diseases, assessing epigenetic factors may be helpful. Also, apart from epigenetic factors, new advances have been made about new mechanisms of and treatments for such a disorder.

The Circulating Micro-RNAs (-122, -34a and -99a) as Predictive Biomarkers for Non-Alcoholic Fatty Liver Diseases

BACKGROUND

It remains essential for patient safety to develop non-invasive diagnostic tools to diagnose non-alcoholic fatty liver rather than invasive techniques.

AIM

Our case-control study was to address the value of circulating miRNAs as a potential non-invasive biomarker for the diagnosis of non-alcoholic fatty acid diseases (NAFLD) and monitoring of disease progression.

METHODS

Routine clinical assessment, laboratory tests, anthropometric study, and liver biopsy results reported for 210 patients with NAFLD (124 patients of simple steatosis (SS) and 86 of non-alcoholic steatohepatitis (NASH)). Apparently matched for age and gender, healthy participants (n= 90) were enrolled as a control group. Serum samples were tested for micro-RNAs (-122, -34a and -99a) by quantitative-PCR.

RESULTS

By histopathology, 124 of the NAFLD group were of SS and 86 patients were of NASH. Compared with the control subjects, both mi-RNA-122 and -34a levels were increased in NAFLD (p< 001) and at a cut-off = 1.261, mi-RNA-122 had 92% sensitivity, 85% specificity to differentiate NAFLD from healthy controls, while mi-RNA-99a were significantly decreased in NAFLD patients with an observed decrease in disease severity, and at a cut-off = 0.46, miRNA-99a had 94% sensitivity and 96% specificity to discriminate SS from NASH.

CONCLUSION

The integration of a circulating mi-RNA panel to diagnose NAFLD cases and to discriminate between SS and NASH. Large-scale study is still needed to verify the other mi-RNA profiles and their role in NAFLD pathogenesis and targeting therapy.

Molecular methods in electrochemical microRNA detection

High-throughput profiling/sensing of nucleic acids has recently emerged as a highly promising strategy for the early diagnosis and improved prognosis of a broad range of pathologies, most notably cancer. Among the potential biomarker candidates, microRNAs (miRNAs), a class of non-coding RNAs of 19-25 nucleotides in length, are of particular interest due to their role in the post-transcriptional regulation of gene expression. Developing miRNA sensing technologies that are quantitative, ultrasensitive and highly specific has proven very challenging because of their small size, low natural abundance and the high degree of sequence similarity among family members. When compared to optical based methods, electrochemical sensors offer many advantages in terms of sensitivity and scalability. This non-comprehensive review aims to break-down and highlight some of the most promising strategies for electrochemical sensing of microRNA biomarkers.

miRNAs in patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND & AIMS

microRNAs (miRNAs) are deregulated in non-alcoholic fatty liver disease (NAFLD) and have been proposed as useful markers for the diagnosis and stratification of disease severity. We conducted a meta-analysis to identify the potential usefulness of miRNA biomarkers in the diagnosis and stratification of NAFLD severity.

METHODS

After a systematic review, circulating miRNA expression consistency and mean fold-changes were analysed using a vote-counting strategy. The sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio and area under the curve (AUC) for the diagnosis of NAFLD or non-alcoholic steatohepatitis (NASH) were pooled using a bivariate meta-analysis. Deeks' funnel plot was used to assess the publication bias.

RESULTS

Thirty-seven studies of miRNA expression profiles and six studies of diagnostic accuracy were ultimately included in the quantitative analysis. miRNA-122 and miRNA-192 showed consistent upregulation. miRNA-122 was upregulated in every scenario used to distinguish NAFLD severity. The miRNA expression correlation between the serum and liver tissue was inconsistent across studies. miRNA-122 distinguished NAFLD from healthy controls with an AUC of 0.82 (95% CI 0.75-0.89), and miRNA-34a distinguished non-alcoholic steatohepatitis (NASH) from non-alcoholic fatty liver (NAFL) with an AUC of 0.78 (95% CI 0.67-0.88).

CONCLUSION

miRNA-34a, miRNA-122 and miRNA-192 were identified as potential diagnostic markers to segregate NAFL from NASH. Both miRNA-122, in distinguishing NAFLD from healthy controls, and miRNA-34a, in distinguishing NASH from NAFL, showed moderate diagnostic accuracy. miRNA-122 was upregulated in every scenario of NAFL, NASH and fibrosis. LAY SUMMARY: microRNAs are deregulated in non-alcoholic fatty liver disease. The microRNAs, miRNA-34a, miRNA-122 and miRNA-192, were identified as potential biomarkers of non-alcoholic fatty liver and non-alcoholic steatohepatitis, at different stages of disease severity. The correlation between miRNA expression in the serum and in liver tissue was inconsistent, or even inverse.

Serum Levels of miR-148a and miR-21-5p Are Increased in Type 1 Diabetic Patients and Correlated with Markers of Bone Strength and Metabolism

Type 1 diabetes (T1D) is characterized by bone loss and altered bone remodeling, resulting into reduction of bone mineral density (BMD) and increased risk of fractures. Identification of specific biomarkers and/or causative factors of diabetic bone fragility is of fundamental importance for an early detection of such alterations and to envisage appropriate therapeutic interventions. MicroRNAs (miRNAs) are small non-coding RNAs which negatively regulate genes expression. Of note, miRNAs can be secreted in biological fluids through their association with different cellular components and, in such context, they may represent both candidate biomarkers and/or mediators of bone metabolism alterations. Here, we aimed at identifying miRNAs differentially expressed in serum of T1D patients and potentially involved in bone loss in type 1 diabetes. We selected six miRNAs previously associated with T1D and bone metabolism: miR-21; miR-24; miR-27a; miR-148a; miR-214; and miR-375. Selected miRNAs were analyzed in sera of 15 T1D patients (age: 33.57 ± 8.17; BMI: 21.4 ± 1.65) and 14 non-diabetic subjects (age: 31.7 ± 8.2; BMI: 24.6 ± 4.34). Calcium, osteocalcin, parathormone (PTH), bone ALkaline Phoshatase (bALP), and Vitamin D (VitD) as well as main parameters of bone health were measured in each patient. We observed an increased expression of miR-148a (p = 0.012) and miR-21-5p (p = 0.034) in sera of T1D patients vs. non-diabetic subjects. The correlation analysis between miRNAs expression and the main parameters of bone metabolism, showed a correlation between miR-148a and Bone Mineral Density (BMD) total body (TB) values (p = 0.042) and PTH circulating levels (p = 0.033) and the association of miR-21-5p to Bone Mineral Content-Femur (BMC-FEM). Finally, miR-148a and miR-21-5p target genes prediction analysis revealed several factors involved in bone development and remodeling, such as MAFB, WNT1, TGFB2, STAT3, or PDCD4, and the co-modulation of common pathways involved in bone homeostasis thus potentially assigning a role to both miR-148a and miR-21-5p in bone metabolism alterations. In conclusion, these results lead us to hypothesize a potential role for miR-148a and miR-21-5p in bone remodeling, thus representing potential biomarkers of bone fragility in T1D.

Advanced microRNA-based cancer diagnostics using amplified time-gated FRET

MicroRNAs (miRNAs) play an important role in cellular functions and in the development and progression of cancer. Precise quantification of endogenous miRNAs from different clinical patient and control samples combined with a one-to-one comparison to standard technologies is a challenging but necessary endeavor that is largely neglected by many emerging fluorescence technologies. Here, we present a simple, precise, sensitive, and specific ratiometric assay for absolute quantification of miRNAs. Isothermally amplified time-gated Förster resonance energy transfer (TG-FRET) between Tb donors and dye acceptors resulted in miRNA assays with single-nucleotide variant specificity and detection limits down to 4.2 ± 0.5 attomoles. Quantification of miR-21 from human tissues and plasma samples revealed the relevance for breast and ovarian cancer diagnostics. Analysis of miR-132 and miR-146a from acute monocytic leukemia cells (THP-1) demonstrated the broad applicability to different miRNAs and other types of clinical samples. Direct comparison to the gold standard RT-qPCR showed advantages of amplified TG-FRET concerning precision and specificity when quantifying low concentrations of miRNAs as required for diagnostic applications. Our results demonstrate that a careful implementation of rolling circle amplification and TG-FRET into one straightforward nucleic acid detection method can significantly advance the possibilities of miRNA-based cancer diagnostics and research.

Effect of miR-30e regulating NK cell activities on immune tolerance of maternal-fetal interface by targeting PRF1

AIM

Natural killer (NK) cells, as key regulatory cells, accumulate at the maternal-fetal interface in large numbers. This study explored the effect of miR-30e on regulating the activity and function of peripheral blood NK cells (PB-NK cells) and decidua NK cells (D-NK cells) by targeting PRF1 in immune tolerance of maternal-fetal interface.

METHODS

Expressions of miR-30e in PB and decidua tissues from 49 patients with recurrent spontaneous abortion and 52 normal pregnant women were measured using PCR. NK cells were isolated from PB and decidua tissues and identified by flow cytometry (FCM). In PB-NK cells and D-NK cells activated by IFN-α, expressions of miR-30e and PRF1 were determined by PCR and Western blot. Negative controls of miR-30e mimics/inhibitors and siRNA against PRF1 were transfected in PB-NK cells and D-NK cells. Expressions of miR-30e and PRF1 were determined and their relationship was verified. Expressions of KIR2DL1, NKp44, IFN-γ, TNF-α, IL-4 and IL-10 were determined by FCM. Cytotoxicity kit was used to identify the cytotoxicity of NK cells. PCR and ELISA were employed to measure expression of VEGF, Ang-2 and PGF in D-NK cells.

RESULTS

After activation by IFN-α, D-NK cells and PB-NK cells showed decreased miR-30e expression and increased PRF1 expression in normal non-pregnant women. PRF1 is a target gene of miR-30e and miR-30e negatively regulated PRF1 expression. The treatment of miR-30e mimics elevated KIR2DL1 expression and decreased NKp44 expression in PB-NK or D-NK cells. Moreover, up-regulation of miR-30e expression suppressed cytotoxicity, corresponding to increased expression of IL-4and IL-10 and reduced expression of IFN-γ and TNF-α in PB-NK and D-NK cells, as well as enhanced expression of VEGF, Ang-2 and PGF in D-NK cells. Transfection of miR-30e inhibitors could reverse the tendencies.

CONCLUSION

Up-regulated miR-30e can reduce the cytotoxicity of PB-NK cells and D-NK cells by targeting PRF1, whereby inhibiting Th1 tolerance phenotype and inducing Th2 immunodominance. miR-30e may be contributive to creating a micro-immune tolerance environment of maternal-fetal interface.

MiR-155, a potential serum marker of extramammary Paget's disease

BACKGROUND

Extramammary Paget's disease (EMPD), a rare skin malignancy with non-specific manifestations, is often misdiagnosed as eczema of scrotum or tinea cruris. Although the diagnosis of EMPD could be confirmed by biopsy, it can be delayed as patients are reluctant to receive invasive operations. Herein, we investigated the serum miRNA expressions of EMPD patients and compared to that of the eczema of scrotum or tinea cruris patients as well as health volunteers for potential diagnostic markers for EMPD.

METHODS

Altogether 45 subjects including 16 patients diagnosed with EMPD, 12 patients diagnosed with eczema of scrotum or tinea cruris and 17 healthy volunteers were enrolled in this study. Serum from all of subjects were collected to identify miRNAs (by miRNA array global normalization, RT-PCR validation, and receiver operating characteristic curve analysis) that could be potential diagnostic markers for EMPD.

RESULTS

The miRNA array analyses revealed that the expressions of 37 miRNAs from the EMPD patients were different (change ≥4-fold) from health volunteers. Among these miRNAs, the expression of miR-155 was significantly increased (p < 0.01) in the EMPD patients as compared with that of the health volunteers and the eczema of scrotum or the tinea cruris patients (no difference between these two control groups). In addition, receiver operating characteristic (ROC) curve analysis showed that diagnostic capacities (defined as the area under curve of ROC) of miR-155 are 0.85 (as compared with health volunteers group) and 0.81 (as compared with the eczema of scrotum or the tinea cruris patients group), respectively.

CONCLUSION

The serum miRNA expression of gene miR-155 in the EMPD patients was differentiated from that of other subjects warranting further validation of miR-155 as a diagnostic marker of EMPD.

Age- and sex-dependent changes in levels of circulating brain-enriched microRNAs during normal aging

Aging is a major risk factor for many common and life-threatening pathologies. The development of reliable biomarkers of aging should lead to a better understanding of aging-associated processes and facilitate the development of therapeutic regimens that delay aging. Levels of 38 brain-enriched microRNAs (miRNA) circulating in plasma were measured by quantitative RT-PCR in two age groups: 26-35 and 56-65 years old. An miRNA-pair approach was used for data normalization and determination of effective miRNA biomarker ratios. Nineteen miRNAs, comprising miRNA pairs and pair combinations (classifiers) that effectively differentiated the age and sex (individual pairs: 74-95% and 68-95%, respectively; classifiers: up to 100% accuracy) groups, were selected for further analysis of plasma samples from 5 donor age groups: 26-35, 36-45, 46-55, 56-65 and 66-75 years old. Dynamic changes in the plasma concentrations of certain miRNAs occurred at different ages in females and males, with peaks in the 46-55-year-old and 56-65-year-old groups, respectively. This finding suggests that the changes in miRNA levels can reflect centrally regulated processes, including changes in hormone levels during menopause. Certain miRNAs and miRNA pairs correlated with age in the sex-stratified groups at different ages and should be investigated further as potentially promising biomarkers of brain aging.

MicroRNAs 143 and 150 in whole blood enable detection of T-cell immunoparalysis in sepsis

Background

Currently, no suitable clinical marker for detection of septic immunosuppression is available. We aimed at identifying microRNAs that could serve as biomarkers of T-cell mediated immunoparalysis in sepsis.

Methods

RNA was isolated from purified T-cells or from whole blood cells obtained from septic patients and healthy volunteers. Differentially regulated miRNAs were identified by miRNA Microarray (n = 7). Validation was performed via qPCR (n = 31).

Results

T-cells of septic patients revealed characteristics of immunosuppression: Pro-inflammatory miR-150 and miR-342 were downregulated, whereas anti-inflammatory miR-15a, miR-16, miR-93, miR-143, miR-223 and miR-424 were upregulated. Assessment of T-cell effector status showed significantly reduced mRNA-levels of IL2, IL7R and ICOS, and increased levels of IL4, IL10 and TGF-β. The individual extent of immunosuppression differed markedly. MicroRNA-143, − 150 and − 223 independently indicated T-cell immunoparalysis and significantly correlated with patient’s IL7R-/ICOS-expression and SOFA-scores. In whole blood, composed of innate and adaptive immune cells, both traits of immunosuppression and hyperinflammation were detected. Importantly, miR-143 and miR-150 – both predominantly expressed in T-cells – retained strong power of discrimination also in whole blood samples.

Conclusions

These findings suggest miR-143 and miR-150 as promising markers for detection of T-cell immunosuppression in whole blood and may help to develop new approaches for miRNA-based diagnostic in sepsis.

Electronic supplementary material

The online version of this article (10.1186/s10020-018-0056-z) contains supplementary material, which is available to authorized users.

MicroRNA-195 as a diagnostic biomarker in human cancer detection: A meta-analysis

MicroRNAs (miRNAs/miRs) show great promise as novel cancer biomarkers. Several studies have revealed an association between abnormal miRNA expression and the risk of various cancer types. However, the diagnostic accuracy and reliability of miRNAs remains unclear. The present meta-analysis was performed to summarize the overall diagnostic performance of miR-195 for cancer. The PubMed, Cochrane Library, Wanfang and China National Knowledge Infrastructure databases were searched for associated literature published until December 10, 2017. Eligible studies were selected using multiple search strategies based on study selection criteria. Measures, including sensitivity and specificity, of the performance of miR-195 as a cancer diagnostic tool were pooled using bivariate meta-analysis models. All analyses were performed using Stata 14.0. The pooled analysis included 8 studies comprising 735 cases and 547 controls. The pooled diagnostic results calculated from all studies were as follows: Sensitivity, 0.79 [95% confidence interval (CI), 0.69–0.87]; specificity, 0.84 (95% CI, 0.68–0.93); positive likelihood ratio, 4.9 (95% CI, 2.50–9.50); negative likelihood ratio, 0.25 (95% CI, 0.18–0.35); diagnostic odds ratio, 20 (95% CI, 10.00–38.00); and area under the curve, 0.87 (95% CI, 0.84–0.90). Deeks' funnel plot asymmetry test suggested no potential publication bias (P=0.53). The present meta-analysis indicated that miR-195 could be a reliable non-invasive biomarker for the diagnosis of cancer. Further large-scale prospective studies are necessary to confirm the present findings and the clinical value of miR-195 for future diagnostics.

miRNA in a multiomic context for diagnosis, treatment monitoring and personalized management of metastatic breast cancer

Metastatic breast cancer is characterized by aggressive spreading to distant organs. Despite huge multilevel research, there are still several important challenges that have to be clarified in the management of this disease. Therefore, recent investigations have implemented a modern, multiomic approach with the aim of identifying specific biomarkers for not only early detection but also to predict treatment responses and metastatic spread. Specific attention is paid to short miRNAs, which regulate gene expression at the post-transcriptional level. Aberrant miRNA expression could initiate cancer development, cell proliferation, invasion, migration, metastatic spread or drug resistance. An miRNA signature is, therefore, believed to be a promising biomarker and prediction tool that could be utilized in all phases of carcinogenesis. This article offers comprehensive information about miRNA profiles useful for diagnostic and treatment purposes that may sufficiently advance breast cancer management and improve individual outcomes in the near future.

Circulating microRNAs and prediction of asthma exacerbation in childhood asthma

BACKGROUND

Circulating microRNAs have shown promise as non-invasive biomarkers and predictors of disease activity. Prior asthma studies using clinical, biochemical and genomic data have not shown excellent prediction of exacerbation. We hypothesized that a panel of circulating microRNAs in a pediatric asthma cohort combined with an exacerbation clinical score might predict exacerbation better than the latter alone.

METHODS

Serum samples from 153 children at randomization in the Childhood Asthma Management Program were profiled for 754 microRNAs. Data dichotomized for asthma exacerbation one year after randomization to inhaled corticosteroid treatment were used for binary logistic regression with miRNA expressions and exacerbation clinical score.

RESULTS

12 of 125 well-detected circulating microRNAs had significant odd ratios for exacerbation with miR-206 being most significant. Each doubling of expression of the 12 microRNA corresponded to a 25-67% increase in exacerbation risk. Stepwise logistic regression yielded a 3-microRNA model (miR-146b, miR-206 and miR-720) that, combined with the exacerbation clinical score, had excellent predictive power with a 0.81 AUROC. These 3 microRNAs were involved in NF-kβ and GSK3/AKT pathways.

CONCLUSIONS

This combined circulating microRNA-clinical score model predicted exacerbation in asthmatic subjects on inhaled corticosteroids better than each constituent feature alone.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00000575 .

Human plasma and serum extracellular small RNA reference profiles and their clinical utility

Nucleic acids mediate storage and expression of genetic information. Extracellular DNA (exDNA) and exRNA are traces of nucleic acids released from cells into the extracellular environment. Their use as disease biomarkers has been limited by technical challenges in their isolation caused by abundant RNA- and DNA-degrading enzymes in biofluids. Using isolation protocols developed especially for biofluids, we generated plasma and serum exRNA reference profiles from 13 healthy volunteers over time and determined the effect of critical clinical parameters such as gender and fasting. Surprisingly, we encountered one participant with dramatically increased endocrine-origin exRNA contributions stable over 1 year and detectable in all of his samples, thereby demonstrating the robustness of this approach and the clinical potential of circulating RNAs as biomarkers.

Circulating extracellular RNAs (exRNAs) have the potential to serve as biomarkers for a wide range of medical conditions. However, limitations in existing exRNA isolation methods and a lack of knowledge on parameters affecting exRNA variability in human samples may hinder their successful discovery and clinical implementation. Using combinations of denaturants, reducing agents, proteolysis, and revised organic extraction, we developed an automated, high-throughput approach for recovery of exRNAs and exDNA from the same biofluid sample. We applied this method to characterize exRNAs from 312 plasma and serum samples collected from 13 healthy volunteers at 12 time points over a 2-month period. Small RNA cDNA library sequencing identified nearly twofold increased epithelial-, muscle-, and neuroendocrine-cell–specific miRNAs in females, while fasting and hormonal cycle showed little effect. External standardization helped to detect quantitative differences in erythrocyte and platelet-specific miRNA contributions and in miRNA concentrations between biofluids. It also helped to identify a study participant with a unique exRNA phenotype featuring a miRNA signature of up to 20-fold elevated endocrine-cell–specific miRNAs and twofold elevated total miRNA concentrations stable for over 1 year. Collectively, these results demonstrate an efficient and quantitative method to discern exRNA phenotypes and suggest that plasma and serum RNA profiles are stable over months and can be routinely monitored in long-term clinical studies.

An increased fraction of circulating miR-363 and miR-16 is particle bound in patients with chronic lymphocytic leukaemia as compared to normal subjects

OBJECTIVES

In vitro culture studies have shown that miR-363 is enriched in extracellular vesicles from chronic lymphocytic leukaemia cells. We wondered whether miR-363 was detectable in plasma, which is an essential precondition for further studies to assess its usefulness as a biomarker. Using samples from two clinical trials: one enrolling patients with advanced disease and the other asymptomatic patients with early stage disease, we determined plasma miR-363 levels and secondly investigated the distribution of this miRNA between plasma and particle bound fractions in patients and normal subjects.

RESULTS

Advanced disease (n = 95) was associated with higher levels of miR-363 than early stage disease (n = 45) or normal subjects (n = 11) but there was no association with markers of prognosis. The distribution of specific miRNA between particle bound and plasma protein fractions was investigated using size exclusion chromatography on plasma from patients (n = 4) and normal subjects (n = 3). ~ 20% of total miR-16 and miR-363 is particle bound in patients while there was no detectable particle bound material in normal subjects. Our work demonstrates that miR-363 levels are raised in chronic lymphocytic leukaemia patients and raises the possibility that distribution of circulating miRNA between plasma fractions differs in health and disease.

miRNAs in platelet-poor blood plasma and purified RNA are highly stable: a confirmatory study

Objective

We wished to re-assess the relative stability of microRNAs (miRNAs) as compared with other RNA molecules, which has been confirmed in many contexts. When bound to Argonaute proteins, miRNAs are protected from degradation, even when released into the extracellular space in ribonucleoprotein complexes, and with or without the protection of membranes in extracellular vesicles. Purified miRNAs also appear to present less of a target for degradation than other RNAs. Although miRNAs are by no means immune to degradation, biological samples subjected to prolonged incubation at room temperature, multiple freeze/thaws, or collection in the presence of inhibitors like heparin, can typically be remediated or used directly for miRNA measurements.

Results

Here, we provide additional confirmation of early, well validated findings on miRNA stability and detectability. Our data also suggest that inadequate depletion of platelets from plasma may explain the occasional report that freeze–thaw cycles can adversely affect plasma miRNA levels. Overall, the repeated observation of miRNA stability is again confirmed.

MicroRNAs in the pathogenesis and treatment of progressive liver injury in NAFLD and liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) increases the risk of various liver injuries, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis, and ultimately hepatocellular carcinoma (HCC). Ample evidence has suggested that aberrant expression of microRNAs (miRNAs) is functionally involved in the activation of cellular stress, inflammation and fibrogenesis in hepatic cells, including hepatocytes, Kupffer and hepatic stellate cells (HSCs), at different pathological stages of NAFLD and liver fibrosis. Here, we overview recent findings on the potential role of miRNAs in the pathogenesis of NAFLD, including lipotoxicity, oxidative stress, metabolic inflammation and fibrogenesis. We critically assess the literatures on both human subjects and animal models of NAFLD and liver fibrosis with miRNA dysregulation and their mechanisms of actions in liver damage. We further highlight the potential use of miRNA mimics or antimiRNAs as therapeutic approaches for the prevention and treatment of NAFLD and liver fibrosis.

Thymectomy lowers the myasthenia gravis biomarker miR-150-5p

Objective

The aim of the study was to analyze the effect of thymectomy on the proposed disease-specific microRNA (miRNA) biomarkers miR-150-5p and miR-21-5p in patients from the prospective randomized trial of thymectomy in myasthenia gravis (MGTX trial) and to evaluate the longitudinal changes in clinical patterns compared with these miRNA levels.

Methods

Serum samples were obtained from 80 patients with MG who were included in the MGTX trial. Thirty-eight patients were randomized to thymectomy plus prednisone treatment, and 42 patients were randomized to prednisone treatment. Serum samples were analyzed for the expression of miR-150-5p and miR-21-5p, with quantitative reverse transcriptase PCR at baseline and at 12, 24, and 36 months after randomization. The inclusion criteria for participation in the MGTX trial were age 18-65 years, generalized myasthenia gravis (Myasthenia Gravis Foundation of America Class II-IV), disease duration of less than 5 years, and seropositivity for acetylcholine receptor antibodies (AChR+).

Results

Patients treated with thymectomy had lower levels of miR-150-5p at 24 months, both compared with baseline values (p = 0.0011) and the prednisone group (p = 0.04). No change in miRNA levels was found in the prednisone group. Levels of miR-21-5p displayed a negative correlation with the prednisone dose within the prednisone-only group (p ≤ 0.001).

Conclusions

Thymectomy lowers the levels of the proposed biomarker miR-150-5p, which strengthens its position as a potential disease-specific biomarker for AChR+ MG.

Circulating levels of miR-122 and nonalcoholic fatty liver disease in pre-pubertal obese children

OBJECTIVES

The liver-specific miR-122 was proposed as biomarker for NAFLD in adults. Here, we investigated the relationship between miR-122 levels, parameters of liver metabolism and NAFLD in pre-pubertal obese children.

METHODS

Parameters of liver metabolism (ALT, AST and GGT) of three European cohorts were included (German cohort [n = 71; age: 11.53 ± 1.29 years; BMI z-score: 2.96 ± 0.64], Italian cohort [n = 45; age: 9.60 ± 2.11 years; BMI z-score: 3.57 ± 1.16], Slovenian cohort [n = 31; age: 7.53 ± 1.47 years; BMI z-score: 3.66 ± 0.88]). MiR-122 levels and CK18 concentrations were measured in fasting blood samples. In the German and Italian cohort, the diagnosis of NAFLD and grading of NAFLD was assessed by ultrasound.

RESULTS

NAFLD was diagnosed in n = 50 patients of the German cohort (29.6%) and in n = 29 patients (72.5%) of the Italian cohort. In all three cohorts, miR-122 was positively correlated with ALT and AST as well as with CK18 concentrations. MiR-122 levels were higher in children with NAFLD compared with healthy controls.

CONCLUSIONS

MiR-122 levels in pre-pubertal obese children could be a potential biomarker for paediatric NAFLD.

Diagnostic value of circulating microRNAs for liver cirrhosis: a meta-analysis

Circulating microRNAs are potential biomarkers for various diseases including liver cirrhosis. We designed a meta-analysis to evaluate the diagnostic value of circulating microRNAs for liver cirrhosis patients. Eligible studies were identified by searching PubMed, Embase, and the Cochrane Library up to July 1, 2017. The diagnostic sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic (AUROC) curve were analyzed using a random or fixed effects models based on the between-study heterogeneities. Thirteen studies from 7 articles with 627 patients and 418 healthy controls were included in this meta-analysis. All studies had high quality assessment scores. The pooled sensitivity, specificity, PLR, NLR, DOR and AUROC were 0.83 (95% CI: 0.80-0.86), 0.89 (95% CI: 0.86-0.92), 6.41 (95% CI: 3.93-10.44), 0.22 (95% CI: 0.14-0.33), 35.18 (95% CI: 15.90-77.81) and 0.93 (95% CI: 0.91-0.95), respectively. In conclusion, circulating microRNAs may serve as potential noninvasive biomarkers of liver cirrhosis.

Droplet Digital PCR for Absolute Quantification of Extracellular MicroRNAs in Plasma and Serum: Quantification of the Cancer Biomarker hsa-miR-141

Droplet-based digital PCR provides high-precision, absolute quantification of nucleic acid target sequences with wide-ranging applications for both research and clinical diagnostic applications. Droplet-based digital PCR enables absolute quantification by counting nucleic acid molecules encapsulated in discrete, volumetrically defined water-in-oil droplet partitions. The current available systems overcome the previous lack of scalable and practical technologies for digital PCR implementation. Extracellular microRNAs in biofluids (plasma, serum, urine, cerebrospinal fluid, etc.) are promising noninvasive biomarkers in multiple diseases and different clinical settings (e.g., diagnosis, early diagnosis, prediction of recurrence, and prognosis). Here we describe a protocol that enables highly precise and reproducible absolute quantification of extracellular microRNAs using droplet digital PCR.

MicroRNAs as biomarkers of acute lung injury

Acute respiratory distress syndrome (ARDS) is a common and complex inflammatory lung diseases affecting critically ill patients requiring mechanical ventilation. MicroRNAs (miRNAs), a novel pathway of non-coding RNA molecules that regulate gene expression at the post-transcriptional level, have emerged as a novel class of gene expression, and can play important roles in inflammation or apoptosis, which are common manifestations of ARDS and diffuse alveolar damage (DAD). In the present review, we discuss the role of miRNAs as biomarkers of ARDS and DAD, and their potential use as therapeutic targets for this condition.

Circulating MicroRNA Expression Levels Associated With Internet Gaming Disorder

BACKGROUND

Addictive use of the Internet and online games is a potential psychiatric disorder termed Internet gaming disorder (IGD). Altered microRNA (miRNA) expression profiles have been reported in blood and brain tissue of patients with certain psychiatric disorders and suggested as biomarkers. However, there have been no reports on blood miRNA profiles in IGD.

METHODS

To discover IGD-associated miRNAs, we analyzed the miRNA expression profiles of 51 samples (25 IGD and 26 controls) using the TaqMan Low Density miRNA Array. For validation, we performed quantitative reverse transcription PCR with 36 independent samples (20 IGD and 16 controls).

RESULTS

Through discovery and independent validation, we identified three miRNAs (hsa-miR-200c-3p, hsa-miR-26b-5p, hsa-miR-652-3p) that were significantly downregulated in the IGD group. Individuals with all three miRNA alterations had a much higher risk of IGD than those with no alteration [odds ratio (OR) 22, 95% CI 2.29-211.11], and the ORs increased dose dependently with number of altered miRNAs. The predicted target genes of the three miRNAs were associated with neural pathways. We explored the protein expression of the three downstream target genes by western blot and confirmed that expression of GABRB2 and DPYSL2 was significantly higher in the IGD group.

CONCLUSION

We observed that expressions of hsa-miR-200c-3p, hsa-miR-26b-5p, and hsa-miR-652-3p were downregulated in the IGD patients. Our results will be helpful to understand the pathophysiology of IGD.

Role of microRNA in the detection, progression, and intervention of acute kidney injury

Acute kidney injury, characterized by sharply decreased renal function, is a common and important complication in hospitalized patients. The pathological mechanism of acute kidney injury is mainly related to immune activation and inflammation. Given the high morbidity and mortality rates of hospitalized patients with acute kidney injury, the identification of biomarkers useful for assessing risk, making an early diagnosis, evaluating the prognosis, and classifying the injury severity is urgently needed. Furthermore, investigation into the development of acute kidney injury and potential therapeutic targets is required. While microRNA was first discovered in Caenorhabditis elegans, Gary Ruvkun's laboratory identified the first microRNA target gene. Together, these two important findings confirmed the existence of a novel post-transcriptional gene regulatory mechanism. Considering that serum creatinine tests often fail in the early detection of AKI, testing for microRNAs as early diagnostic biomarkers has shown great potential. Numerous studies have identified microRNAs that can serve as biomarkers for the detection of acute kidney injury. In addition, as microRNAs can control the expression of multiple proteins through hundreds or thousands of targets influencing multiple signaling pathways, the number of studies on the functions of microRNAs in AKI progression is increasing. Here, we mainly focus on research into microRNAs as biomarkers and explorations of their functions in acute kidney injury. Impact statement Firstly, we have discussed the potential advantages and limitations of miRNA as biomarkers. Secondly, we have summarized the role of miRNA in the progress of AKI. Finally, we have made a vision of miRNA's potential and advantages as therapeutic target intervention AKI.

Serum MicroRNA-27b as a Screening Biomarker for Left Ventricular Hypertrophy

MicroRNA-27b (miR-27b) is frequently upregulated in pressure-overloaded hypertrophic hearts. The clinical implications of aberrant circulating miR-27b in the diagnosis and management of left ventricular hypertrophy warrant study. We investigated whether serum miR-27b is a biomarker for left ventricular hypertrophy (LVH). We used stem-loop reverse-transcription quantitative polymerase chain reaction techniques to analyze serum miR-27b levels in 200 hypertensive patients with LVH, 100 hypertensive patients without LVH, and 100 healthy volunteers. We found that serum miR-27b levels were significantly higher in the hypertensive patients with LVH than in the hypertensive patients without LVH and in the healthy volunteers. Upon receiver operating characteristic curve analysis, serum miR-27b had an area under the curve of 0.885 with 91% sensitivity and 73% specificity in distinguishing hypertensive patients with LVH from healthy volunteers (P=0.021), and an area under the curve of 0.818 with 79.1% sensitivity and 70.3% specificity in distinguishing hypertensive patients with LVH from those without LVH (P=0.036). We conclude that circulating miR-27b might serve as a specific, noninvasive biomarker in screening for LVH.

Circulating brain-enriched microRNAs as novel biomarkers for detection and differentiation of neurodegenerative diseases

Background

Minimally invasive specific biomarkers of neurodegenerative diseases (NDs) would facilitate patient selection and disease progression monitoring. We describe the assessment of circulating brain-enriched microRNAs as potential biomarkers for Alzheimer’s disease (AD), frontotemporal dementia (FTD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS).

Methods

In this case-control study, the plasma samples were collected from 250 research participants with a clinical diagnosis of AD, FTD, PD, and ALS, as well as from age- and sex-matched control subjects (n = 50 for each group), recruited from 2003 to 2015 at the University of Pennsylvania Health System, including the Alzheimer’s Disease Center, the Parkinson’s Disease and Movement Disorders Center, the Frontotemporal Degeneration Center, and the Amyotrophic Lateral Sclerosis Clinic. Each group was randomly divided into training and confirmation sets of equal size. To evaluate the potential of circulating microRNAs enriched in specific brain regions affected by NDs and present in synapses as biomarkers of NDs, the levels of 37 brain-enriched and inflammation-associated microRNAs in the plasma of all participants were measured using individual qRT-PCR. A “microRNA pair” approach was used for data normalization.

Results

MicroRNA pairs and their combinations (classifiers) capable of differentiating NDs from control and from each other were defined using independently and jointly analyzed training and confirmation datasets. AD, PD, FTD, and ALS are differentiated from control with accuracy of 0.89, 0.90, 0.88, and 0.83 (AUCs, 0.96, 0.96, 0.94, and 0.93), respectively; NDs are differentiated from each other with accuracy ranging from 0.77 (AUC, 0.87) for AD vs. FTD to 0.93 (AUC, 0.98) for AD vs. ALS. The data further indicate sex dependence of some microRNA markers. The average increase in accuracy in distinguishing ND from control for all and male/female groups is 0.06; the largest increase is for ALS, from 0.83 for all participants to 0.92/0.98 for male/female participants.

Conclusions

The work presented here suggests the possibility of developing microRNA-based diagnostics for detection and differentiation of NDs. Larger multicenter clinical studies are needed to further evaluate circulating brain-enriched microRNAs as biomarkers for NDs and to investigate their association with other ND biomarkers in clinical trial settings.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-017-0316-0) contains supplementary material, which is available to authorized users.

Down-regulated serum microRNA-101 is associated with aggressive progression and poor prognosis of cervical cancer

OBJECTIVE

MicroRNAs (miRNAs) play a vital role in pathogenesis and progression of many cancers, including cervical cancer. However, importance of serum level of miR-101 in cervical cancer has rarely been studied. In the present study, clinical significance and prognostic value of serum miR-101 for cervical cancer was investigated.

METHODS

Association between miR-101 level in cervical cancer tissues and prognosis of patients was analyzed by using data retrieved from The Cancer Genome Atlas (TCGA) database, which was followed with our clinical study in which miR-101 serum level comparison between cervical cancer patients and healthy controls was conducted by real-time quantitative polymerase chain reaction (PCR).

RESULTS

TCGA database demonstrated that miR-101 was down-regulated in cervical cancer tissues compared with normal cervical tissues, and univariate Cox regression analysis indicated that decreased miR-101 expression was a highly significant negative risk factor. Similar trend was found in the serum miR-101. Serum level of miR-101 was associated with International Federation of Gynecology and Obstetrics (FIGO) stage (p=0.003), lymph node metastasis (p=0.001), and serum squamous cell carcinoma antigen (SCC-Ag) level >4 (p=0.007). The overall survival time of cervical cancer patients with a higher level of serum miR-101 was significantly longer than that of patients with a lower level of serum miR-101. Moreover, multivariate Cox regression analysis indicated that the down-regulated serum level of miR-101 was an independent predictor for the unfavorable prognosis of cervical cancer.

CONCLUSION

Serum level of miR-101 is closely associated with metastasis and prognosis of cervical cancer; and, hence could be a potential biomarker and prognostic predictor for cervical cancer.

MicroRNAs in Taenia solium Neurocysticercosis: Insights as Promising Agents in Host-Parasite Interaction and Their Potential as Biomarkers

MicroRNAs (miRNAs) are short, endogenous, non-coding, single-stranded RNAs involved in post-transcriptional gene regulation. Although, several miRNAs have been identified in parasitic helminths, there is little information about their identification and function in Taenia. Furthermore, the impact of miRNAs in neurocysticercosis, the brain infection caused by larvae of Taenia solium is still unknown. During chronic infection, T. solium may activate numerous mechanisms aimed to modulate host immune responses. Helminthic miRNAs might also have effects on host mRNA expression and thus play an important role regulating host-parasite interactions. Also, the diagnosis of this disease is difficult and it usually requires neuroimaging and confirmatory serology. Since miRNAs are stable when released, they can be detected in body fluids and therefore have potential to diagnose infection, determine parasite burden, and ascertain effectiveness of treatment or disease progression, for instance. This review discusses the potential roles of miRNAs in T. solium infection, including regulation of host-parasite relationships and their eventual use as diagnostic or disease biomarkers. Additionally, we summarize the bioinformatics resources available for identification of T. solium miRNAs and prediction of their targets.

Expression and Regulatory Network Analysis of miR-140-3p, a New Potential Serum Biomarker for Autism Spectrum Disorder

Given its prevalence and social impact, Autism Spectrum Disorder (ASD) is drawing much interest. Molecular basis of ASD is heterogeneous and only partially known. Many factors, including disorders comorbid with ASD, like TS (Tourette Syndrome), complicate ASD behavior-based diagnosis and make it vulnerable to bias. To further investigate ASD etiology and to identify potential biomarkers to support its precise diagnosis, we used TaqMan Low Density Array technology to profile serum miRNAs from ASD, TS, and TS+ASD patients, and unaffected controls (NCs). Through validation assays in 30 ASD, 24 TS, and 25 TS+ASD patients and 25 NCs, we demonstrated that miR-140-3p is upregulated in ASD vs.: NC, TS, and TS+ASD (Tukey's test, p-values = 0.03, = 0.01, < 0.0001, respectively). ΔCt values for miR-140-3p and YGTSS (Yale Global Tic Severity Scale) scores are positively correlated (Spearman r = 0.33; Benjamini-Hochberg p = 0.008) and show a linear relationship (p = 0.002). Network functional analysis showed that nodes controlled by miR-140-3p, especially CD38 and NRIP1 which are its validated targets, are involved in processes convergingly dysregulated in ASD, such as synaptic plasticity, immune response, and chromatin binding. Biomarker analysis proved that serum miR-140-3p can discriminate among: (1) ASD and NC (Area under the ROC curve, AUC: 0.70; sensitivity: 63.33%; specificity: 68%); (2) ASD and TS (AUC: 0.72; sensitivity: 66.66%; specificity: 70.83%); (3) ASD and TS+ASD (AUC: 0.78; sensitivity: 73.33%; specificity: 76%). Characterization of miR-140-3p network would contribute to further clarify ASD etiology. Serum miR-140-3p could represent a potential non-invasive biomarker for ASD, easy to test through liquid biopsy.