Circulating microRNAs: Biomarkers of disease

MicroRNAs are a class of endogenous noncoding single-stranded RNA molecules with approximately 20-24 nucleotides and are associated with a broad range of biological processes. Researchers found that microRNAs are abundant in tissues, and more importantly, there are also trace circulating microRNAs that exist in biological fluids. In recent years, circulating microRNAs had emerged as promising diagnostic and prognostic biomarkers for the noninvasive detection of diseases with high specificity and sensitivity. More importantly, specific microRNA expression signatures reflect not only the existence of early-stage diseases but also the dynamic development of advanced-stage diseases, disease prognosis prediction, and drug resistance. To date, an increasing number of potential miRNA biomarkers have been reported, but their practical application prospects are still unclear. Therefore, microRNAs, as potential diagnostic and prognostic biomarkers in a variety of diseases, need to be updated, as they are of great importance in the diagnosis, prognosis and prediction of therapeutic responses. In this review, we summary our current understanding of microRNAs as potential biomarkers in the major diseases (e.g., cancers and cardio-cerebrovascular diseases), which provide the basis for the design of diagnosis and treatment plan and the improvement of the cure rate.

Recent progress in the use of microRNAs as biomarkers for drug-induced toxicities in contrast to traditional biomarkers: A comparative review

microRNAs (miRNAs) are small non-coding RNAs with 18-25 nucleotides. They play key regulatory roles in versatile biological process including development and apoptosis, and in disease pathogenesis, for example carcinogenesis, by negatively regulating gene expression. miRNAs often exhibit characteristics suitable for biomarkers such as tissue-specific expression patterns, high stability in serum/plasma, and change in abundance in circulation immediately after toxic injury. Since the discovery of circulating miRNAs in extracellular biological fluids in 2008, there have been many reports on the use of miRNAs as biomarkers for various diseases including cancer and organ injury in humans and experimental animals. In this review article, we have summarized the utility and limitation of circulating miRNAs as safety/toxicology biomarkers for specific tissue injuries including liver, skeletal muscle, heart, retina, and pancreas, by comparing them with conventional protein biomarkers. We have also covered the discovery of miRNAs in serum/plasma and their stability, the knowledge of which is essential for understanding the kinetics of miRNA biomarkers. Since numerous studies have reported the use of these circulating miRNAs as safety biomarkers with high sensitivity and specificity, we believe that circulating miRNAs can promote pre-clinical drug development and improve the monitoring of tissue injuries in clinical pharmacotherapy.

Exosomal hsa-miR-933 in Gastric Juice as a Potential Biomarker for Functional Dyspepsia

BACKGROUND

MicroRNAs (miRNAs) in exosomes represent disease-specific profiles and are applied as biomarkers in oncology. However, in functional dyspepsia (FD), the role of exosomal miRNAs has not been fully elucidated.

AIMS

To investigate exosomal miRNAs as potential biomarkers of FD using liquid biopsy.

METHODS

This retrospective cohort study included 11 subjects with FD and 11 age- and sex-matched healthy controls (HCs). We collected gastric juice and isolated exosomal miRNAs. In a discovery cohort, expression levels of 2565 miRNAs were evaluated by 3D-Gene^® microarray. miRNA expression profiles from exosomes of subjects with FD and HCs were compared by two normalization methods: (1) global normalization and (2) normalization by internal control. Subsequently, in a validation cohort, the expression levels of miRNAs were validated by quantitative reverse transcription PCR (RT-qPCR).

RESULTS

Through microarray analysis using the two methods, we identified 39 miRNAs that were consistently and significantly downregulated in FD cases compared with those in HCs. Of these, 12 miRNAs (hsa-miR-933, hsa-miR-345-5p, hsa-miR-708-5p, hsa-miR-203a-3p, hsa-miR-619-5p, hsa-miR-4294, hsa-miR-4481, hsa-miR-196a-5p, hsa-miR-3918, hsa-miR-372-3p, hsa-miR-658, and hsa-miR-3654) were further validated by RT-qPCR. Our results indicated that hsa-miR-933 was significantly downregulated in FD compared with HCs (0.317 ± 0.205-fold, P = 0.0317). Furthermore, the expression level of hsa-miR-933 was negatively associated with dyspepsia score and the frequency of epigastric pain and/or burning (P < 0.01, r = - 0.835; P = 0.0280, r = - 0.688, respectively).

CONCLUSIONS

Exosomal hsa-miR-933 in gastric juice could be a candidate biomarker for FD.

Circulating microRNAs as biomarkers for diagnosis and prediction of preeclampsia: A systematic review and meta-analysis

OBJECTIVE

We carried out a meta-analysis to quantitatively summarize the overall diagnostic and predictive effects of circulating microRNAs in diagnosis and prediction of preeclampsia, respectively.

STUDY DESIGN

We screened selected databases and systematically retrieved articles until September 20th, 2019 for analysis. After literature screening and data extraction, we firstly conducted quality assessment according to QUADAS-2 score system. And then the pooled diagnostic and predictive parameters were calculated using a bivariate random-effect meta-analysis model. We used threshold effect analysis and subgroup analysis to identify the sources of heterogeneity. The clinical utility was validated through the Fagan's Nomogram. Sensitivity analysis was performed to assess the reliability of each included study, and we evaluated publication bias with the Deeks' funnel plot asymmetry test.

RESULTS

The meta-analysis included 8 articles comprising 273 preeclampsia patients and 343 normal pregnancies. Pooled results of diagnostic values of 5 articles indicated a sensitivity of 0.88 (95 %CI: 0.80-0.93), specificity of 0.87 (95 %CI: 0.78-0.92) and diagnostic odds ratio of 50.24 (95 %CI: 21.28-118.62). The pooled sensitivity, specificity, DOR of circulating microRNAs for predicting preeclampsia of asymptomatic pregnancies were 0.61 (95 %CI: 0.55-0.68), 0.78 (95 %CI: 0.72-0.83) and 5.7 (95 %CI: 3.7-8.7) across other 3 articles. Subgroup analysis revealed that non-plasma specimen type, non-U6 reference gene and non-Asian had better diagnostic value while due to limited data, we did not conduct a subgroup analysis of predictive value.

CONCLUSIONS

Circulating miRNAs distinguish patients with preeclampsia from controls with relatively high diagnostic and predictive accuracy. Then we conclude that circulating miRNAs could be a useful screening tool to diagnose and predict preeclampsia. However, its utility should be judged with caution and large-sample prospective studies are warranted to explore if its implementation improves maternal and neonatal outcomes.

Macronutrient modulation of mRNA and microRNA function in animals: A review

Dietary macronutrients have been regarded as a basic source of energy and amino acids that are necessary for the maintenance of cellular homeostasis, metabolic programming as well as protein synthesis. Due to the emergence of “nutrigenomics”, a unique discipline that combines nutritional and omics technologies to study the impacts of nutrition on genomics, it is increasingly evident that macronutrients also have a significant role in the gene expression regulation. Gene expression is a complex phenomenon controlled by several signaling pathways and could be influenced by a wide variety of environmental and physiological factors. Dietary macronutrients are the most important environmental factor influencing the expression of both genes and microRNAs (miRNA). miRNA are tiny molecules of 18 to 22 nucleotides long that regulate the expression of genes. Therefore, dietary macronutrients can influence the expression of genes in both direct and indirect manners. Recent advancements in the state-of-the-art technologies regarding molecular genetics, such as next-generation sequencing, quantitative PCR array, and microarray, allowed us to investigate the occurrence of genome-wide changes in the expression of genes in relation to augmented or reduced dietary macronutrient intake. The purpose of this review is to accumulate the current knowledge focusing on macronutrient mediated changes in the gene function. This review will discuss the impact of altered dietary carbohydrate, protein, and fat intake on the expression of coding genes and their functions. In addition, it will also summarize the regulation of miRNA, both cellular and extracellular miRNA, expression modulated by dietary macronutrients.

Circulating miR-1 as a potential predictor of left ventricular remodeling following acute ST-segment myocardial infarction using cardiac magnetic resonance

Background

The identification of patients with a high likelihood of left ventricular (LV) remodeling with a high-risk prognosis has critical implications for risk stratification after acute ST-segment elevation myocardial infarction (STEMI). This study aimed to evaluate the relationship between circulating miR-1 and 6-month post-infarct LV remodeling based on cardiac magnetic resonance (CMR) imaging.

Methods

A total of 80 patients with a first STEMI treated with primary percutaneous coronary intervention (PCI) who underwent CMR imaging 1 week and 6 months after STEMI were evaluated. The percentage changes of LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV end-systolic volume index (LVESV) at 1 week and 6 months after PCI (%ΔLVEF, %ΔLVEDV and %ΔLVESV) were calculated. miR-1 was measured using polymerase chain reaction (PCR)-based technologies in plasma samples that were collected at admission. The study group was divided into two groups based on a 10% cutoff value for the percentage of change in the LV end-diastolic volume (%ΔLVEDV): remodeling at high risk of major adverse cardiac events (MACEs) (%ΔLVEDV ≥10%, termed the LV remodeling group) and remodeling at lower risk of MACEs (%ΔLVEDV <10%, termed the non-LV remodeling group). The associations of miR-1 expression with the %ΔLVEDV, percentage change in the LV end-systolic volume (%ΔLVESV), and percentage change in the LV ejection fraction at follow-up were estimated.

Results

Twenty-two patients (27.5%) showed adverse LV remodeling, and 58 patients (72.5%) did not show adverse LV remodeling at the 6-month follow-up of CMR. The mean LVEF, LVEDV index, and LVESV index values at 1 week were 50.6%±8.2%, 74.6±12.8 mL/m², and 37.2±10.2 mL/m², respectively. Mean LVEF at follow-up (53.5%±10.6%) was increased compared with baseline (P<0.001). There were significant decreases in LVEDV index and LVESV index values at follow-up (72.0±14.9 mL/m² and 33.7±11.0 mL/m², respectively; P=0.009 and P<0.001, respectively). The expression of miR-1 at admission was positively correlated with the %ΔLVEDV (r=0.611, P<0.001) and %ΔLVESV (r=0.268, P=0.016). Receiver operating characteristic (ROC) analysis showed that miR-1 expression predicted LV remodeling with an area under the curve (AUC) value of 0.68 (95% CI: 0.56-0.78). Compared with the clinical factors of peak creatine kinase-myocardial band (CK-MB) and peak troponin T level, peak logNT-proBNP showed the highest predictive power, with an AUC value of 0.75 (95% CI: 0.64-0.84). A model including the clinical, CMR, and miR-1 factors showed greater predictive power (P=0.034) than a model including only clinical and CMR factors, with AUCs of 0.89 (95% CI: 0.80-0.95) and 0.81 (95% CI: 0.71-0.89), respectively.

Conclusions

Circulating miR-1 at admission is an independent predictor of LV remodeling 6 months after STEMI. miR-1 showed incremental value in predicting LV remodeling compared with the clinical and CMR measurements.

Serum outperforms plasma in small extracellular vesicle microRNA biomarker studies of adenocarcinoma of the esophagus

BACKGROUND

Circulating microRNAs (miRNAs) are potential biomarkers for many diseases. However, they can originate from non-disease specific sources, such as blood cells, and compromise the investigations for miRNA biomarkers. While small extracellular vesicles (sEVs) have been suggested to provide a purer source of circulating miRNAs for biomarkers discovery, the most suitable blood sample for sEV miRNA biomarker studies has not been defined.

AIM

To compare the miRNA profiles between matched serum and plasma sEV preparations to determine their suitability for biomarker studies.

METHODS

Matched serum and plasma samples were obtained from 10 healthy controls and 10 patients with esophageal adenocarcinoma. sEV isolates were prepared from serum and plasma using ExoQuick^TM and quantified using NanoSight. RNA was extracted from sEV preparations with the miRNeasy Serum/Plasma kit and profiled using the Taqman Openarray qPCR. The overall miRNA content and the expression of specific miRNAs of reported vesicular and non-vesicular origins were compared between serum and plasma sEV preparations. The diagnostic performance of a previously identified multi-miRNA biomarker panel for esophageal adenocarcinoma was also compared.

RESULTS

The overall miRNA content was higher in plasma sEV preparations (480 miRNAs) and contained 97.5% of the miRNAs found in the serum sEV preparations (412 miRNAs).The expression of commonly expressed miRNAs was highly correlated (Spearman’s R = 0.87, P < 0.0001) between the plasma and serum sEV preparations, but was consistently higher in the plasma sEV preparations. Specific blood-cell miRNAs (hsa-miR-223-3p, hsa-miR-451a, miR-19b-3p, hsa-miR-17-5p, hsa-miR-30b-5p, hsa-miR-106a-5p, hsa-miR-150-5p and hsa-miR-92a-3p) were expressed at 2.7 to 9.6 fold higher levels in the plasma sEV preparations compared to serum sEV preparations (P < 0.05). In plasma sEV preparations, the percentage of protein-associated miRNAs expressed at relatively higher levels (Ct 20-25) was greater than serum sEV preparations (50% vs 31%). While the percentage of vesicle-associated miRNAs expressed at relatively higher levels was greater in the serum sEV preparations than plasma sEV preparations (70% vs 44%). A 5-miRNA biomarker panel produced a higher cross validated accuracy for discriminating patients with esophageal adenocarcinoma from healthy controls using serum sEV preparations compared with plasma sEV preparations (AUROC 0.80 vs 0.54, P < 0.05).

CONCLUSION

Although plasma sEV preparations contained more miRNAs than serum sEV preparations, they also contained more miRNAs from non-vesicle origins. Serum appears to be more suitable than plasma for sEV miRNAs biomarkers studies.

The diagnostic, prognostic and therapeutic potential of circulating microRNAs in ovarian cancer

Ovarian cancer (OC) is often diagnosed at an advanced stage because of the late onset of symptoms, and this together with the lack of effective treatments, has meant it is associated with a very high mortality. The aberrant expression of MicroRNA (miRNA) contributes to the initiation and development of human tumors including OC. Several miRNAs are secreted by tumor cells and can be identified in body fluids. Serum miRNAs levels are associated with several clinical conditions, and may be used to predict prognosis and response to treatments in some cancers including OC. This review summarizes the current progresses regarding the potential applications of circulating miRNA as innovative biomarkers in OC.

Circulating MicroRNA-423-3p Improves the Prediction of Coronary Artery Disease in a General Population - Six-Year Follow-up Results From the China-Cardiovascular Disease Study

BACKGROUND

Circulating microRNAs (miRNA) are potential prognostic biomarkers for cardiovascular disease. We aimed to identify serum miRNA as an effective predictor for coronary artery disease (CAD) events in a general population cohort.Methods and Results:Serum miRNAs associated with CAD were determined by small RNA sequencing and quantitative RT-PCR. Further, the predictive ability of identified serum miRNAs was measured in a general population of 2,812 people. As a main outcome measure, CAD events were collected for 6 years and included acute myocardial infarction and subsequent myocardial infarction. Out of the 48 miRNA candidates, 5 miRNAs (miR-10a-5p, miR-126-3p, miR-210-3p, miR-423-3p and miR-92a-3p) showed better reliability and repeatability in serum. Then, the association of serum levels of the 5 miRNAs with CAD was validated. Furthermore, miR-10a-5p and miR-423-3p, which showed better performance, were tested in the large cohort, with a median follow up of 6.0 years. In multivariable Cox regression analysis, only miR-423-3p (P for trend<0.001) was able to precisely predict CAD events. Moreover, the addition of circulating miR-423-3p with the traditional risk factors together markedly improved the various model performance measures, including the area under the operating characteristics curve (0.782 vs. 0.806), Akaike Information Criterion (965.845 vs. 943.113) and net reclassification improvement (19.18%).

CONCLUSIONS

Circulating miR-423-3p can improve the prediction of primary CAD outcomes on the basis of a traditional risk factor model in general population.

3D DNA nanonet structure coupled with target-catalyzed hairpin assembly for dual-signal synergistically amplified electrochemical sensing of circulating microRNA

DNA nanomaterials are reliable and powerful tools in the development of a variety of biosensors owing to their notable self-assembly ability and precise recognition capability. Here, we propose a DNA nanomaterial-based system for the dual-amplified electrochemical sensing of circulating microRNAs by a coupled cascade of catalyzed hairpin assembly (CHA) and three-dimensional (3D) DNA nanonet structure. In the target-assisted CHA process, the stable hairpin structures H1 and H2 act as probes for the recognition and recycling of circulating microRNAs, leading to the formation of abundant H1-H2 duplexes with tails. Subsequently, a 3D DNA nanonet structure was introduced, which was assembled using three DNA strands constructed X-DNA monomers as the building blocks, and hybridized to the tails of H1-H2 duplexes. The successful integration of target-assisted CHA and 3D DNA nanonet structure induced the second signal amplification. The designed biosensor performed under optimized experimental conditions, and exposed admirable analytical performance for the detection of circulating miR-21, with a wide linear range from 10 fM to 1 nM, high sensitivity of limit of detection (LOD) of 3.6083 fM, good specificity in the face of single nucleotides and other microRNAs, satisfactory stability and reproducibility for practical analysis. Furthermore, the clinical applicability for circulating miR-21 detection was verified in human serum samples without additional treatment. We hope that this elaborated biosensor will provide new opportunities for bioassays based on DNA nanomaterials.

Serum miR-338-3p and miR-199b-5p are associated with the absolute neutrophil count in patients with resectable pancreatic cancer

BACKGROUND

Several peripheral blood cell counts and immune ratios, such as the systemic immune-inflammation index (SII = platelet x neutrophil count/lymphocyte count) have prognostic value in patients with resectable pancreatic cancer (PDAC). Circulating microRNAs (miRNAs) are involved in various aspects of cancer and inflammation. We aimed to identify measurable circulating miRNAs in PDAC patients correlating with systemic inflammation parameters.

METHODS

A total of 42 PDAC patients was included in this study: twelve in the discovery (n = 6 SII low; n = 6 SII high) and 30 patients in the validation cohort (n = 19 SII low, n = 11 SII high). MiRNAs isolated from preoperative serum samples were measured with a 352 miRNA panel in the discovery cohort and individual miRNA primers in the validation cohort, using RT-qPCR (ID3EAL assays, MiRXES).

RESULTS

Only in the discovery cohort miR-328-3p, miR-338-3p, miR-1258 and miR-199b-5p were upregulated in high compared to low SII patients (fold difference ≥ 2, P<0.05). In the total cohort (n = 42) correlations were found between miR-338-3p (r = 0.48, P = 0.002) and miR-199b-5p (r = 0.44, P = 0.005) and the absolute neutrophil count.

CONCLUSION

Circulating miR-338-3p and miR-199b-5p are correlated to the neutrophil count in the blood of PDAC patients, suggesting a potential role of circulating miRNAs in cancer immune evasion and systemic inflammation.

Circulating miR-103 family as potential biomarkers for type 2 diabetes through targeting CAV-1 and SFRP4

AIMS

MicroRNA-103 (miR-103) family plays important roles in regulating glucose homeostasis in type 2 diabetes mellitus (DM2). However, the underlying mechanisms remain poorly characterized. The objective of this study was to test the hypothesis that circulating miR-103a and miR-103b, which regulate CAV-1 and SFRP4, respectively, are novel biomarkers for diagnosis of DM2.

METHODS

We determined the predictive potential of circulating miR-103a and miR-103b in pre-DM subjects (pre-DM), noncomplicated diabetic subjects, and normal glucose-tolerance individuals (control) using bioinformatic analysis, qRT-PCR, luciferase assays, and ELISA assays.

RESULTS

We found that both miR-103a and miR-103b had high complementarity and conservation, modulated reporter gene expression through seed sequences in the 3'UTRs of CAV-1 and SFRP4 mRNA, and negatively regulated their mRNA and protein levels, respectively. We also found that increased miR-103a and decreased miR-103a in plasma were significantly and negatively correlated with reduced CAV-1 levels and elevated SFRP4 levels in pre-DM and DM2, respectively, and were significantly associated with glucose metabolism, HbA1c levels, and other DM2 risk factors for progression from a normal individual to one with pre-DM. Furthermore, we demonstrated that the reciprocal changes in circulating miR-103a and miR-103b not only provided high sensitivity and specificity to differentiate the pre-DM population but also acted as biomarkers for predicting DM2 with high diagnostic value.

CONCLUSIONS

These findings suggest that circulating miR-103a and miR-103b may serve as novel biomarkers for diagnosis of DM2, providing novel insight into the mechanisms underlying pre-DM.

Circulating microRNAs as biomarkers in cancer diagnosis

MicroRNAs (miRNAs) are a group of tiny molecules of 18-22 nucleotide long noncoding RNA that regulate the post-transcriptional gene expression through translational inhibition and/or mRNA destabilization. Because of their involvement in important developmental processes, it is highly likely that the altered expression of miRNAs could be associated with abnormal conditions like suboptimal growth or diseases. Thus, the expression of miRNAs can be used as biomarkers in pathophysiological conditions. Recently, a handful of miRNAs are detected in cell-free conditions including biofluids and cell culture media and they exhibit specific expression patterns that are associated with altered physiological conditions. Extracellular miRNAs are not only extremely stable outside cells in a variety of biofluids but also they are easy to acquire. These characteristics led to the idea of using extracellular miRNAs as a potential biomarker for the onset and prognosis of cancer. Although miRNAs have been proposed as a potential diagnostic tool for cancer detection, their application in the routine clinical investigation is yet to come. First, this review will provide an insight into the extracellular miRNAs, particularly, their release mechanisms and characteristics, and the potential of extracellular miRNAs as a biomarker in cancer detection. Finally, it will discuss the potential of using extracellular miRNAs in different cancer diagnoses and challenges associated with the clinical application of extracellular miRNAs as noninvasive biomarkers.

High level of circulating microRNA-142 is associated with acute myocardial infarction and reduced survival

BACKGROUND

Recent study reported that microRNA-142 (miR-142) were up-regulated in the atherosclerotic plaques, which may be responsible for pathogenesis of atherosclerosis. However, whether it associates with presence of acute myocardial infarction (AMI), and its prognostic value is still unknown. We, therefore, investigated the association between miR-142 expression and presence of AMI, and its prognostic value in AMI patients.

METHODS

We included 300 AMI patients and 100 subjects as the control group. MiR-142 content was detected by quantitative real-time polymerase chain reaction. MiR-142 level was identified in all subjects. The multivariate logistic regression analysis were performed to evaluate the risk factors of AMI. The Kaplan-Meier analysis was performed to determine the major adverse cardiovascular and cerebrovascular events (MACCE)-free survival.

RESULTS

AMI group had significantly higher miR-142 level in comparison to the controls [4.10 (2.03-7.43) vs. 1.92 (0.91-2.91), p < 0.001], moreover, miR-142 content was significantly associated with cardiac troponin I (cTnI) level (r = 0.707, p < 0.001). The MACCE-free survival was significantly lower over 24-month for patients in miR-142 high expression group (72.4% ± 5.6% vs. 76.4% ± 5.1%) (p = 0.022). After adjusting for the traditional risk factors, the odds ratios of miR-142 was 14.74 (95% CI, 2.15-101.24). The multivariate logistic regression analysis revealed that miR-142 level significantly associated with presence of AMI (p < 0.001).

CONCLUSION

The serum level of miR-142 was increased in AMI patients when compared with health population. Furthermore, use of this marker may allow a certain predictor of the MACCE in AMI patients.

MicroRNA levels in bone and blood change during bisphosphonate and teriparatide therapy in an animal model of postmenopausal osteoporosis

MicroRNAs control the activity of a variety of genes that are pivotal to bone metabolism. Therefore, the clinical utility of miRNAs as biomarkers and drug targets for bone diseases certainly merits further investigation. This study describes the use of an animal model of postmenopausal osteoporosis to generate a comprehensive dataset on miRNA regulation in bone tissue and peripheral blood during bone loss and specifically anti-resorptive and osteo-anabolic treatment. Forty-two Sprague-Dawley rats were randomized to SHAM surgery (n=10) or ovariectomy (OVX, n=32). Eight weeks after surgery, OVX animals were further randomized to anti-resorptive treatment with zoledronate (n=11), osteo-anabolic treatment with teriparatide (n=11), or vehicle treatment (n=10). After 12 weeks of treatment, bone and serum samples were used for microRNA analysis using next-generation sequencing (NGS), mRNA levels using RT-qPCR, and bone microarchitecture analysis using nanoCT. Ovariectomy resulted in loss of trabecular bone, which was fully rescued using osteo-anabolic treatment, and partially rescued using anti-resorptive treatment. NGS revealed that both, anti-resorptive and anabolic treatment had a significant impact on miRNA levels in bone tissue and serum: out of 426 detected miRNAs, 46 miRNAs were regulated by teriparatide treatment an d 10 by zoledronate treatment (p-adj.<0.1). Interestingly, teriparatide and zoledronate treatment were able to revert miRNA changes in tissue and serum of untreated OVX animals, such as the up-regulation of miR-203a-3p, a known osteo-inhibitory miRNA. We confirmed previously established mechanisms of miR-203a by analyzing its direct target Dlx5 in femoral head. Our data reveal a significant effect of ovariectomy-induced bone loss, as well as the two major types of anti-osteoporotic treatment on miRNA transcription in femoral head tissue. These changes are associated with altered activity of target genes relevant to bone formation, such as Dlx5. The observed effects of bone loss and treatment response on miRNA levels in bone are also reflected in the peripheral blood, suggesting the possibility of minimally-invasive monitoring of bone-derived miRNAs using liquid biopsies.

Expression profiles of candidate microRNAs in the peripheral blood leukocytes of patients with early- and late-onset preeclampsia versus normal pregnancies

OBJECTIVES

Maternal leucocytes play an important role in the pathogenesis of preeclampsia (PE). Circulating microRNAs (miRNAs) are small, noncoding RNA molecules. The purpose of this study was to investigate miR-518b, miR-155-5p, and miR-21-3p in the peripheral blood leukocytes of patients with PE, compared to controls.

STUDY DESIGN

Using real-time quantitative PCR method, the selected miRNAs which have been associated with PE were examined from early- onset PE (EOPE) (<34 weeks) (n = 48), late- onset PE (LOPE) (≥34 weeks) (n = 48), total cases of PE (n = 96), and healthy controls (n = 52).

MAIN OUTCOME MEASURES

The relative expression of the target miR in patient samples was compared to the calibrator and the results were expressed as relative quantification values.

RESULTS

Gestational age (GA) was significantly different between PE and controls. Univariate logistic regression analysis adjusted for GA at blood draw were fit to compare miR-518b, miR-155-5p, and miR-21-3p between PE and controls. The expression of miR-518b, miR-155-5p, and miR-21-3p were not significantly different in PE, compared to controls. The expression of miR-518b was upregulated in the EOPE and LOPE group, compared to controls, and the area under the receiver operating characteristic curve (AUC) of miR-518b was 0.65 and 0.62, respectively. miR-518b was positively correlated with WBC count, platelet count, serum levels of AST, ALT, LDH in EOPE. miR-21-3p expression level was negatively correlated with body mass index at blood draw and systolic blood pressure in the LOPE group.

CONCLUSIONS

Increased miR-518b expression levels were found to be associated with EOPE and LOPE.

Serum microRNAs as novel biomarkers for osteoporotic vertebral fractures

CONTEXT

Vertebral fractures are the hallmark of osteoporosis. MicroRNAs (miRNAs) are a prominent class of gene regulators likely to affect bone homeostasis, including bone remodelling and fracture healing by altering gene expression in bone cells.

OBJECTIVE

This study sought to compare the levels of circulating miRNAs in older women with osteoporotic vertebral fractures, and/or low BMD and healthy controls, and to correlate miRNAs expression levels with BTMs.

DESIGN

A single-site, case-control, observational, cross-sectional study at a university hospital.

PARTICIPANTS

Altogether, 126 postmenopausal women belonging to four different groups were included: healthy (n=42), low BMD and no vertebral fractures (n=39), vertebral fractures and low BMD without a treatment (n=26), or receiving a treatment for osteoporosis (n=19).

MAIN OUTCOME MEASURE

Serum samples from all participants were analyzed for 21 microRNA bone biomarkers.

RESULTS

We identified 7 significantly (p<0.05) up-regulated miRNAs (miR-375, miR-532-3p, miR-19b-3p, miR-152-3p, miR-23a-3p, miR-335-5p, miR-21-5p) in patients with vertebral fractures and low BMD compared to low BMD and healthy individuals, regardless of osteoporosis treatment. No significant differences existed between low BMD and healthy controls. We observed 24 significant correlations (P<0.05) between miRNAs and BTMs (CTX, PINP, OC and bone ALP).

CONCLUSIONS

Specific circulating miRNAs reflect the presence of osteoporotic vertebral fractures in postmenopausal women. They are unlikely to reflect low BMD, and more likely changes in bone quality or fracture healing. The effects of osteoporosis treatment on the selected miRNAs appear to be weaker than effects caused by vertebral fractures. The correlation between miRNAs and BTMs suggest that miRNAs may be involved in bone turnover or fracture healing.

Circulating MicroRNAs as Potential Biomarkers for Lung Cancer

Lung cancer is the number one cause of cancer-related mortality worldwide. To improve disease outcome, it is crucial to implement biomarkers into the clinics which assist physicians in their decisions regarding diagnosis, prognosis, as well as prediction of treatment response. Liquid biopsy offers an opportunity to obtain such biomarkers in a minimal invasive manner by retrieving tumor-derived material from body fluids of the patient. The abundance of circulating microRNAs is known to be altered in disease and has therefore been studied extensively as a cancer biomarker. Circulating microRNAs present a variety of favorable characteristics for application as liquid biopsy-based biomarkers, including their high stability, relatively high abundance, and presence is nearly all body fluids. Although the application of circulating microRNAs for the management of lung cancer has not entered the clinics yet, several studies showed their utility for diagnosis, prognosis, and efficacy prediction of various treatment strategies, including surgery, radio-/chemotherapy, as well as targeted therapy. To compensate for their limited tumor specificity, several microRNAs are frequently combined into microRNA panels. Moreover, the possibility to combine single microRNAs or microRNA panels with tumor imaging or other cancer-specific biomarkers has the potential to increase specificity and sensitivity and could lead to the clinical application of novel multi-marker combinations.

Circulating microRNAs as biomarkers for early diagnosis of cutaneous melanoma

Introduction: Cutaneous melanoma is the deadliest form of skin cancer, with a dramatic increase in the incidence rate worldwide over the past decade. Early detection has been shown to improve the outcome of melanoma patients. The identification of noninvasive biomarkers able to identify melanoma at an early stage remains an unmet clinical need. Circulating miRNAs (c-miRNAs), small non-coding RNAs, appear as potential ideal candidate biomarkers due to their stability in biological fluids and easy detectability. Moreover, c-miRNAs are reported to be heavily deregulated in cancer patients.Areas covered: This review examines evidence of the specific c-miRNAs or panels of c-miRNAs reported to be useful in discriminating melanoma from benign cutaneous lesions.Expert opinion: Although the interesting reported by published studies, the non-homogeneity of detection and normalization methods prevents the individuation of single c-miRNA or panel of c-miRNAs that are specific for early detection of cutaneous melanoma. In the future, prospective wide and well-designed clinical trials will be needed to validate the diagnostic potential of some of the c-miRNA candidates in clinical practice.

Circulating miR-30c as a predictive biomarker of type 2 diabetes mellitus with coronary heart disease by regulating PAI-1/VN interactions

AIMS

Type 2 diabetes mellitus (DM2) is associated with coronary heart disease (CHD) and is characterized by high levels of plasminogen activator inhibitor (PAI)-1. Circulating microRNAs have been reported as potential diagnostic biomarkers for DM2 and CHD. However, the underlying mechanisms have largely remained unclear.

MAIN METHODS

The changes of circulating miR-30c, PAI-1 and vitronetin (VN) in plasma from CHD, noncomplicated (NC) + DM2, CHD + DM2 subjects and control individuals were assessed by quantitative reverse transcription PCR (qRT-PCR) and ELISA assays, respectively. The effects of miR-30c on VN expression by targeting PAI-1 were assessed in vitro SMC and in ex vivo plasma, using bioinformatic analysis, miRNA transfection, luciferase assays, qRT-PCR and western blot, respectively.

KEY FINDINGS

We found that decreased circulating miR-30c was negatively correlated with the severity of coronary lesions and the resulting elevated PAI-1 and VN levels. Circulating miR-30c significantly distinguished between patients with CHD + DM2, NC + DM2, CHD and control subjects, and that were significantly associated with certain risk factors for progression from a normal individual to one with CHD + DM2. Furthermore, we also showed that miR-30c plays a previously unrecognized role in regulating the expression of VN levels via regulating PAI-1 levels in vitro SMC and in ex vivo plasma.

SIGNIFICANCE

These findings provide a novel regulatory mechanism of miR-30c in regulating PAI-1/VN interactions and that may serve as a diagnostic biomarker of DM2 that is complicated with CHD.

Circulating microRNA as biomarkers of clozapine-induced cardiotoxicity

Purpose: This work investigated the utility of circulating microRNA (miRNA) as biomarkers of clozapine (CLZ)-induced cardiotoxicities: serious adverse events with an unusually high incidence in Australia and New Zealand.Methods: Global plasma miRNA expression was analysed by microarray in patients taking CLZ, to investigate differential expression between CLZ-induced cardiotoxicity cases (n = 6) and matched control patients (n = 12). The results were validated by RT-qPCR using a panel of 17 miRNA, and their expression was examined in both CLZ-naïve healthy volunteers (n = 12) and an expanded cohort of CLZ-taking patients (n = 21). Temporal changes were also examined in two healthy volunteers and two CLZ-induced cardiotoxicity patients.Results: No miRNA were differentially expressed between cases of CLZ-induced cardiotoxicity and control patients. Circulating levels of several miRNA were significantly altered in CLZ-taking patients compared to healthy volunteers, with miR-16-5p, miR-25-3p, miR-92a-3p, miR-320a-3p, and miR-486-3p upregulated and miR-22-3p, miR-126-3p, and miR-142-3p downregulated in the patients. Five of these (miR-16-5p, miR-22-3p, miR-92a-3p, miR-126-3p, miR-142-3p) were stably expressed over time in both CLZ-induced cardiotoxicity patients and CLZ-naïve healthy volunteers.Conclusions: Plasma miRNA are not useful biomarkers of CLZ-induced cardiotoxicity, however patients taking CLZ have significantly altered circulating miRNA compared to healthy volunteers.

Circulating miR-34a and miR-125b as Promising non Invasive Biomarkers in Egyptian Locally Advanced Breast Cancer Patients

Background:

Breast cancer (BC) is the second most common cancer worldwide. MicroRNAs are a group of non-coding, single stranded RNAs of ~ 22 nucleotides, which regulate gene expression at the post-transcriptional level. Circulating miRNAs have been found as potential blood based predictive biomarkers.

Purpose:

we aim to evaluate miR-34a and miR-125b to predict outcome from neoadjuvant chemotherapy in Egyptian BC patients.

Methodology:

Quantitative assessment of plasma miR-34a and miR-125b expression was performed by qRT-PCR. Thirty nine newly diagnosed locally advanced BC female patients with 10 age and sex matched healthy volunteers were included in the study.

Results:

We performed ROC curve analysis to evaluate the diagnostic value for the miR-34a with AUCs = 0.995, cutoff point of 2.57 sensitivity 97.4%, specificity 100%, PPV 100%, NPV 83.3% and accuracy 97.7%.miR-125b had AUC = 0.68 and a cutoff point of 8.69 with sensitivity 66.7%, specificity 70.0%, PPV 90.6%, NPV 41.2% and accuracy 73.5%. miR-34a expression were significantly higher in BC patients compared to controls with p value <0.001*. Also, miR-34a expression level was significantly higher in patients with progressive disease with P value =0.03*. However, miR-125b expression levels were insignificantly higher in responsive patients with p value = 0.2.

Conclusion:

miRNAs are crucial candidates for novel molecular targeted therapies due to their capability to regulate numerous genes in molecular pathways. Our data suggest that circulating miR-34a and miR-125b expression levels could be promising highly accurate non-invasive biomarkers in diagnosing BCs. miR-34a can predict chemotherapeutic resistance associated with higher expression levels in non-responsive patients.

Downregulations of circulating miR-31 and miR-21 are associated with preeclampsia

MicroRNAs (miRNAs/miRs) are highly stable in circulating, which suppress target gene expression by base-pairing to the 3'-untranslated region. We compared the expressions of 3 circulating miRs (miR-31, miR-21, and miR-16), which are related to the control of cell apoptosis, invasion, angiogenesis and immune tolerance in non-pregnancy (n = 10), 20-34 gestational weeks normal pregnancy (20-34 GW NP, n = 20), early onset preeclampsia (EOPE, n = 20), 34-41 gestational weeks normal pregnancy (34-41 GW NP, n = 20) and late onset preeclampsia (LOPE, n = 20). Using quantitative RT-PCR, we found the levels of miR-31, miR-21 and miR-16 changed throughout different stages of pregnancy with the non-pregnancy as the calibrator. The plasma miR-31 levels were significantly down-regulated in EOPE rather than in LOPE when compared to gestational age matched normal pregnancy (P < 0.001). MiR-21 levels were significantly lower in LOPE compared to healthy controls (P < 0.001), while no significant difference was found between EOPE and 20-34 gestational weeks normal pregnancy (P = 0.376). The miR-16 expressions were at similar levels between preeclampsia (PE) and normal pregnancy. Receiver operating characteristic (ROC) curve analyses indicated the miR-31 differentiated EOPE patients from healthy controls with an area under the curve (AUC) of 0.875 with 95.0% sensitivity and 70.0% specificity. ROC curves also discriminated the LOPE patients from healthy pregnancy with an AUC of 0.793, 65.1% sensitivity and 90.3% specificity for plasma miR-21 levels. This study is the first to demonstrate the difference, and circulating miR-31 may serve as a diagnostic biomarker for early onset preeclampsia meanwhile miR-21 might be a diagnostic biomarker for late onset preeclampsia.

Circulating microRNA in cardiovascular disease

Acute myocardial infarction (AMI) and heart failure (HF) are two major causes of cardiovascular mortality and morbidity. Early diagnosis of these conditions is essential to instigate immediate treatment that may result in improved outcomes. Traditional biomarkers of AMI include cardiac troponins and other proteins released from the injured myocardium but there are a number of limitations with these biomarkers especially with regard to specificity. In the past few years circulating nucleic acids, notably microRNA that are small non-coding RNAs that regulate various cellular processes, have been investigated as biomarkers of disease offering improved sensitivity and specificity in the diagnosis and prognostication of various conditions. In this review, the role of microRNAs as biomarkers used in the diagnosis of AMI and HF is discussed, their advantage over traditional biomarkers is outlined and the potential for their implementation in clinical practice is critically assessed.

Associations of serum microRNA-20a, -27a, and -103a with cognitive function in a Japanese population: The Yakumo study

OBJECTIVES

MicroRNAs (miRNAs) dysregulate gene expression by binding to target messenger RNAs, and play an important role in the pathogenesis of various diseases, including cancers, cardiovascular diseases and diabetes. Circulating miRNAs have increasingly been recognized as biomarkers for detecting and diagnosing those diseases. Few studies have investigated the association of circulating miRNA with the early stages of cognitive impairment, such as mild cognitive impairment, in the general population. The purpose of this study was to examine the association between cognitive function and several serum miRNAs levels related to amyloid precursor protein (APP) proteolysis in a Japanese general population who had never been diagnosed with dementia.

METHODS

We conducted a cross-sectional study of 337 Japanese subjects (144 men, 193 women) who attended a health examination. The short form of the Mini-Mental State Examination (SMMSE) was used to assess cognitive function. Serum levels of 6 miRNAs (let-7d, miR-17, miR-20a, miR-27a, miR-34a, miR-103a) were measured by quantitative real-time polymerase chain reaction.

RESULTS

Multivariable-adjusted odds ratios (ORs) for lower SMMSE score (SMMSE score < 28) were significantly increased in the lowest tertile of serum miR-20a (OR, 2.08; 95% confidence interval (CI), 1.09-4.04) and miR-103a (OR, 1.91; 95%CI, 1.00-3.69) compared to the highest tertile. Moreover, serum levels of miR-20a, -27a, and -103a were linearly and positively associated with SMMSE scores after adjustment for confounding factors.

CONCLUSION

Low serum levels of miR-20a, -27a, and -103a are independently associated with cognitive impairment.