Plasma miR-208 as a biomarker of myocardial injury

Lessons from basic pancreatic beta cell research in type-2 diabetes and vascular complications

The changes in life-style with increased access of food and reduced physical activity have resulted in the global epidemic of obesity. Consequently, individuals with type 2 diabetes and cardiovascular disease have also escalated. A central organ in the development of diabetes is the pancreas, and more specifically the pancreatic beta cells within the islets of Langerhans. Beta cells have been assigned the important task of secreting insulin when blood glucose is increased to lower the glucose level. An early sign of diabetes pathogenesis is lack of first phase insulin response and reduced second phase secretion. In this review, which is based on the foreign investigator award lecture given at the JSDC meeting in Sendai in October 2016, we discuss a possible cellular explanation for the reduced first phase insulin response and how this can be influenced by lipids. Moreover, since patients with cardiovascular disease and high levels of cholesterol are often treated with statins, we summarize recent data regarding effects on statins on glucose homeostasis and insulin secretion. Finally, we suggest microRNAs (miRNAs) as central players in the adjustment of beta cell function during the development of diabetes. We specifically discuss miRNAs regarding their involvement in insulin secretion regulation, differential expression in type 2 diabetes, and potential as biomarkers for prediction of diabetes and cardiovascular complications.

MicroRNA Biomarkers in Neurodegenerative Diseases and Emerging Nano-Sensors Technology

MicroRNAs (miRNAs) are essential small RNA molecules (20–24 nt) that negatively regulate the expression of target genes at the post-transcriptional level. Due to their roles in a variety of biological processes, the aberrant expression profiles of miRNAs have been identified as biomarkers for many diseases, such as cancer, diabetes, cardiovascular disease and neurodegenerative diseases. In order to precisely, rapidly and economically monitor the expression of miRNAs, many cutting-edge nanotechnologies have been developed. One of the nanotechnologies, based on DNA encapsulated silver nanoclusters (DNA/AgNCs), has increasingly been adopted to create nanoscale bio-sensing systems due to its attractive optical properties, such as brightness, tuneable emission wavelengths and photostability. Using the DNA/AgNCs sensor methods, the presence of miRNAs can be detected simply by monitoring the fluorescence alteration of DNA/AgNCs sensors. We introduce these DNA/ AgNCs sensor methods and discuss their possible applications for detecting miRNA biomarkers in neurodegenerative diseases.

MicroRNAs in Cardiovascular Disease: Perspectives and Reality

Since the discovery of the first noncoding RNA decades ago, the transcriptomics evolution has made a great leap reaching to the detection and recognition of microRNAs (miRNAs) in the early 1990s. Thereafter, numerous miRNAs were reported in different species, with a great body of literature focusing on their role in human health and in pathophysiological processes. miRNAs play a significant role in the cardiovascular system, not only in physiology and normal development but also in disease processes and evolution. Further studies on miRNAs have highlighted their participation in several expressions of cardiovascular disease, such as atherosclerosis, acute and chronic syndromes of coronary artery disease, heart failure, and cardiac arrhythmias. To date, the challenge remains to understand the underlying mechanisms of miRNAs that drive their expression profile so as to use them as innovative diagnostic tools or therapeutic targets in cardiovascular disease.

Electrochemical DNA biosensors based on long-range electron transfer: investigating the efficiency of a fluidic channel microelectrode compared to an ultramicroelectrode in a two-electrode setup

Here, we describe the transposition of an ultramicroelectrode (UME) setup into a microfluidic chip configuration for DNA biosensors. The hydrodynamic properties of the fluidic channel microelectrode were screened with an [Fe(iii)(CN)₆]^3-/[Fe(ii)(CN)₆]^4- redox couple by cyclic voltammetry to provide a basis for further biological processes. A 23-base DNA probe was self-assembled into a monolayer on gold microelectrodes both in classical configuration and integrated in a microfluidic setup. Special interest was focused on the DNA target mimicking the liver-specific micro-ribonucleic acid 122 (miRNA122). Long-range electron transfer was chosen for transducing the hybridization. This direct transduction was indeed significantly enhanced after hybridization due to DNA-duplex π-stacking and the use of redox methylene blue as a DNA intercalator. Quantification of the target was deduced from the resulting electrical signal characterized by cyclic voltammetry. The limit of detection for DNA hybridization was 0.1 fM in stopped flow experiments, where it can reach 1 aM over a 0.5 μL s^-1 flow rate, a value 10⁴-fold lower than the one measured with a conventional UME dipped into an electrolyte droplet under the same analytical conditions. An explanation was that forced convection drives more biomolecules to the area of detection even if a balance between the speed of collection and the number of biomolecules collected has been found. The latter point is discussed here along with an attempt to explain why the sensor has reached such an unexpected value for the limit of detection.

[Translational medicine in Russian cardiology: a new stage or repetition of the past?]

The brief review gives the experience in using the concept of translational medicine in the practical activities of the Russian Cardiology Research and Production Complex in the past 25 years of its existence. It outlines the possible ways of developing this area in Russian medicine to solve crucial scientific and practical tasks.

MiR-155 Enhances Insulin Sensitivity by Coordinated Regulation of Multiple Genes in Mice

miR-155 plays critical roles in numerous physiological and pathological processes, however, its function in the regulation of blood glucose homeostasis and insulin sensitivity and underlying mechanisms remain unknown. Here, we reveal that miR-155 levels are downregulated in serum from type 2 diabetes (T2D) patients, suggesting that miR-155 might be involved in blood glucose control and diabetes. Gain-of-function and loss-of-function studies in mice demonstrate that miR-155 has no effects on the pancreatic β-cell proliferation and function. Global transgenic overexpression of miR-155 in mice leads to hypoglycaemia, improved glucose tolerance and insulin sensitivity. Conversely, miR-155 deficiency in mice causes hyperglycemia, impaired glucose tolerance and insulin resistance. In addition, consistent with a positive regulatory role of miR-155 in glucose metabolism, miR-155 positively modulates glucose uptake in all cell types examined, while mice overexpressing miR-155 transgene show enhanced glycolysis, and insulin-stimulated AKT and IRS-1 phosphorylation in liver, adipose tissue or skeletal muscle. Furthermore, we reveal these aforementioned phenomena occur, at least partially, through miR-155-mediated repression of important negative regulators (i.e. C/EBPβ, HDAC4 and SOCS1) of insulin signaling. Taken together, these findings demonstrate, for the first time, that miR-155 is a positive regulator of insulin sensitivity with potential applications for diabetes treatment.

Optimized Collection Protocol for Plasma MicroRNA Measurement in Patients with Cardiovascular Disease

Background. Various microRNAs (miRNAs) are used as markers of acute coronary syndrome, in which heparinization is considered mandatory therapy. Nevertheless, a standard method of handling plasma samples has not been proposed, and the effects of heparin treatment on miRNA detection are rarely discussed. Materials and Method. This study used quantitative polymerase chain reaction (qPCR) analysis to investigate how storage temperature, standby time, hemolysis, and heparin treatment affect miRNA measurement in plasma samples from 25 patients undergoing cardiac catheterization. Results. For most miRNAs, the qPCR results remained consistent during the first 2 hours. The miRNA signals did not significantly differ between samples stored at 4°C before processing and samples stored at room temperature (RT) before processing. miR-451a/miR-23a ratio < 60 indicated < 0.12% hemolysis with 100% sensitivity and 100% specificity. Pretreatment with 0.25 U heparinase I recovered qPCR signals that were reduced by in vivo heparinization. Conclusions. For miRNA measurement, blood samples stored at RT should be processed into plasma within 2 hours after withdrawal and should be pretreated with 0.25 U heparinase I to overcome heparin-attenuated miRNA signals. The miR-451a/miR-23a ratio is a reliable indicator of significant hemolysis.

Recent progress toward the use of circulating microRNAs as clinical biomarkers

MicroRNAs (miRNAs) have been shown to be critical mediators of many cellular and developmental processes and have been implicated in different human diseases. Since the observation of extracellular miRNAs present in various biofluids, much attention and excitement have been garnered toward understanding the functional roles of these circulating extracellular miRNAs and establishing their potential use as noninvasive diagnostic biomarkers. Here, we will review the current state of miRNA biomarkers for many human diseases, including their emerging use in toxicological applications, and discuss the current challenges in the field, with an emphasis on technical issues that often hinder discovery-based miRNA biomarker studies.

Circulating Organ-Specific MicroRNAs Serve as Biomarkers in Organ-Specific Diseases: Implications for Organ Allo- and Xeno-Transplantation

Different cell types possess different miRNA expression profiles, and cell/tissue/organ-specific miRNAs (or profiles) indicate different diseases. Circulating miRNA is either actively secreted by living cells or passively released during cell death. Circulating cell/tissue/organ-specific miRNA may serve as a non-invasive biomarker for allo- or xeno-transplantation to monitor organ survival and immune rejection. In this review, we summarize the proof of concept that circulating organ-specific miRNAs serve as non-invasive biomarkers for a wide spectrum of clinical organ-specific manifestations such as liver-related disease, heart-related disease, kidney-related disease, and lung-related disease. Furthermore, we summarize how circulating organ-specific miRNAs may have advantages over conventional methods for monitoring immune rejection in organ transplantation. Finally, we discuss the implications and challenges of applying miRNA to monitor organ survival and immune rejection in allo- or xeno-transplantation.

Analysis of plasma miR-208a and miR-370 expression levels for early diagnosis of coronary artery disease

Coronary artery disease (CAD) requires more accurate diagnostic methods, for which circulating microRNAs (miRNAs) are promising non-invasive biomarkers. miR-208a and miR-370 are two key molecules in cardiac hemostasis and lipid metabolism, respectively. The aim of the present study was to evaluate their potency as diagnostic biomarkers for CAD. Plasma miR-208a and miR-370 were quantitated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) using a TaqMan^® MicroRNA Reverse Transcription and PCR kit in 95 CAD patients and 50 non-CAD control subjects. The association between the miRNA levels and CAD was analyzed statistically. The plasma levels of miR-208a (P=0.006) and miR-370 (P=0.003) were significantly higher in the CAD group than in the control group. Using receiver operating characteristic analysis it was shown that the area under the curve (AUC) of miR-208a and miR-370 was 0.819 and 0.745, respectively. The combination of miR-208a and miR-370 exhibited the largest AUC of 0.856. Thus, miR-208a and miR-370 are promising diagnostic biomarkers for discriminating CAD and may facilitate the management of patient care. The combination of the two miRNAs may be more efficacious than either miRNA alone for the diagnosis of CAD.

Plasma-specific microRNA response induced by acute exposure to aristolochic acid I in rats

Aristolochic acid I (AAI) derived from a natural herbal alkaloid is a nephrotoxicant. AAI-induced acute kidney injury (AKI), a devastating clinical disease associated with high mortality rates, is difficult for early diagnosis. To address this issue, we identified and validated early-detection biomarkers for AAI-induced acute kidney injury via profiling microRNA expression in rats. Global miRNA expression profile analysis found that 21 miRNAs were significantly dysregulated in kidney of rats treated by 40 mg/kg AAI on day 2, day 4, or day 6, among which 5 miRNAs were upregulated at all three time points. Quantitative RT-PCR confirmed that miR-21-3p on day 4 and day 6 was obviously upregulated in kidney of rats treated by 40 mg/kg AAI. Further examination found that miR-21-3p was increased in plasma early on day 2 in 10 mg/kg AAI-treated rats, but not in non-target organs. Importantly, the elevation of plasma miR-21-3p preceded the increase in blood urea nitrogen and creatinine, and the presence of renal tubular injury, characterized by differential increase before and after the presence of renal tubular lesions. Our findings thus show that miRNA expression is upregulated in kidney and plasma of AKI rat induced by AAI, and plasma miR-21-3p may be served as a new potential biomarker for early diagnosing AAI-induced acute kidney injury in rats, and possibly in humans.

Identification and Evaluation of Novel MicroRNA Biomarkers in Plasma and Feces Associated with Drug-induced Intestinal Toxicity

Gastrointestinal toxicity is dose limiting with many therapeutic and anticancer agents. Real-time, noninvasive detection of markers of toxicity in biofluids is advantageous. Ongoing research has revealed microRNAs as potential diagnostic and predictive biomarkers for the detection of select organ toxicities. To study the potential utility of microRNA biomarkers of intestinal injury in a preclinical toxicology species, we evaluated 3 rodent models of drug-induced intestinal toxicity, each with a distinct mechanism of toxicity. MiR-215 and miR-194 were identified as putative intestinal toxicity biomarkers. Both were evaluated in plasma and feces and compared to plasma citrulline, an established intestinal injury biomarker. Following intestinal toxicant dosing, microRNA changes in feces and plasma were detected noninvasively and correlated with histologic evidence of intestinal injury. Fecal miR-215 and miR-194 levels increased, and plasma miR-215 decreased in a dose- and time-dependent manner. Dose-dependent decreases in plasma miR-215 levels also preceded and correlated positively with plasma citrulline modulation, suggesting miR-215 is a more sensitive biomarker. Moreover, during the drug-free recovery phase, plasma miR-215 returned to predose levels, supporting a corresponding recovery of histologic lesions. Despite limitations, this study provides preliminary evidence that select microRNAs have the potential to act as noninvasive, sensitive, and quantitative biomarkers of intestinal injury.

Circulating microRNAs indicate cardioprotection by sevoflurane inhalation in patients undergoing off-pump coronary artery bypass surgery

In patients undergoing off-pump coronary artery bypass surgery (OPCAB), it is important to attenuate myocardium injury during the surgery. The present study aimed to observe the cardioprotection induced by sevoflurane induction and maintenance compared with propofol intravenous anesthesia, and to detect its potential protection against acute myocardial injury with sensitive biomarkers. In total, 36 patients undergoing OPCAB were randomly assigned into two groups, receiving sevoflurane (n=18) or propofol (n=18) as the induction and maintenance anesthetic agent. The depth of anesthesia in the two groups was kept at a bispectral index value of 40-50. Physiological and hemodynamic parameters were recorded during the surgery. Cardiac troponin-I (cTnI), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and two microRNAs (miR-499 and miR-208b) were also measured during and subsequent to surgery. Nno statistically significant differences were observed in the physiological and hemodynamic parameters between the two groups prior to surgery. Following surgery, the cardiac output and stroke volume improved significantly in the sevoflurane group (P<0.05). In addition, patients in the sevoflurane group had lower miR-499 (P<0.05) and miR-208b (P<0.01) levels at 12 h after surgery when compared with the propofol group. However, no significant differences in cTnI, CK-MB and LDH levels were observed following surgery between the two groups. In conclusion, volatile induction and maintenance with sevoflurane resulted in some extent of cardiac function improvement in patients undergoing OPCAB. Cardioprotection by sevoflurane is suggested by reduced cardiac injury compared with propofol, and indicated by the sensitive biomarkers, circulating miR-499 and miR-208b.

MicroRNA-208b Alleviates Post-Infarction Myocardial Fibrosis in a Rat Model by Inhibiting GATA4

BACKGROUND Myocardial infarction affects the health of many people. Post-infarction myocardial fibrosis has attracted much attention, but details of the mechanism remain elusive. In this study, the role of microRNA-208b (miR-208b) in modulating post-infarction myocardial fibrosis and the related mechanism were investigated. MATERIAL AND METHODS A rat model of myocardial infarction induced by ligating the left anterior descending artery was used to analyze the expression and roles of miR-208b by overexpression with the lentivirus vector of pre-miR-208b. Myocardial function was assessed and the expression of fibrosis-related factors type I collagen (COL1) and ACTA2 (alias αSMA) was detected. Myocardial fibroblasts isolated from newborn rats were transfected with luciferase reporter vectors containing wild-type or mutant Gata4 3' UTR to verify the relationship between Gata4 and miR-208b. We then transfected the specific small interference RNA of Gata4 to detect changes in COL1 and ACTA2. RESULTS miR-208b was down-regulated in hearts of model rats (P<0.01). Overexpressing miR-208b improved myocardial functions, such as reducing the infarction area (P<0.05) and promoting LVEF and LVFS (P<0.01), and inhibited COL1 and ACTA2 (P<0.01). Luciferase reporter assay proved Gata4 to be the direct target of miR-208b, with the target sequence in the 3'UTR. Inhibiting GATA4 resulted in the down-regulation of COL1 and ACTA2, suggesting that the role of miR-208b was achieved via regulating GATA4. CONCLUSIONS This study demonstrates the protective function of miR-208b via GATA4 in post-infarction myocardial fibrosis, providing a potential therapeutic target for treating myocardial fibrosis.

Circulating microRNAs predict future fatal myocardial infarction in healthy individuals - The HUNT study

Coronary heart disease is the most common cause of death, and the number of individuals at risk is increasing. To better manage this pandemic, improved tool for risk prediction, including more accurate biomarkers are needed. The objective of this study was to assess the utility of circulating microRNAs (miRs) to predict future fatal acute myocardial infarction (AMI) in healthy participants. We performed a prospective nested case-control study with 10-year observation period and fatal AMI as endpoint. In total, 179 miRs were quantified by real-time polymerase chain reaction in serum of 112 healthy participants (40-70years) that either (1) suffered from fatal AMI within 10years [n=56], or (2) remained healthy [n=56, risk factor-matched controls]. Candidate miRs were validated in a separate cohort of healthy individuals (n=100). Twelve miRs were differently expressed in cases and controls in the derivation cohort (p<0.05). Among these, 10 miRs differed significantly between cases and controls in the validation cohort (p<0.05). We identified gender dimorphisms, as miR-424-5p and miR-26a-5p were associated exclusively with risk in men and women, respectively. The best model for predicting future AMI consisted of miR-106a-5p, miR-424-5p, let-7g-5p, miR-144-3p and miR-660-5p, providing 77.6% correct classification for both genders, and 74.1% and 81.8% for men and women, respectively. Adding these 5 miRs to the Framingham Risk Score, increased the AUC from 0.72 to 0.91 (p<0.001). In conclusion, we identified several miRs associated with future AMI, revealed gender-specific associations, and proposed a panel of 5 miRs to enhance AMI risk prediction in healthy individuals.

Point-of-care diagnostics for niche applications

Point-of-care or point-of-use diagnostics are analytical devices that provide clinically relevant information without the need for a core clinical laboratory. In this review we define point-of-care diagnostics as portable versions of assays performed in a traditional clinical chemistry laboratory. This review discusses five areas relevant to human and animal health where increased attention could produce significant impact: veterinary medicine, space travel, sports medicine, emergency medicine, and operating room efficiency. For each of these areas, clinical need, available commercial products, and ongoing research into new devices are highlighted.

microRNAs in ischaemic cardiovascular diseases

microRNAs (miRNAs) are non-coding RNA molecules that modulate the stability and/or the translational efficiency of specific messenger RNAs. They have been shown to play a regulatory role in most biological processes and their expression is disrupted in many cardiovascular diseases. This review describes studies performed at Policlinico San Donato-IRCCS in cell cultures, animal models, and patients, showing a penetrant role of miRNAs in cell response to hypoxia and in ischaemic cardiovascular diseases. These experiments indicate miRNA as an emerging class of therapeutic targets.

MicroRNA-223 Attenuates Hypoxia-induced Vascular Remodeling by Targeting RhoB/MLC2 in Pulmonary Arterial Smooth Muscle Cells

There is growing evidence that microRNAs are implicated in pulmonary arterial hypertension (PAH), but underlying mechanisms remain elusive. Here, we identified that miR-223 was significantly downregulated in chronically hypoxic mouse and rat lungs, as well as in pulmonary artery and pulmonary artery smooth muscle cells (PASMC) exposed to hypoxia. Knockdown of miR-223 increased PASMC proliferation. In contrast, miR-223 overexpression abrogated cell proliferation, migration and stress fiber formation. Administering miR-223 agomir in vivo antagonized hypoxia-induced increase in pulmonary artery pressure and distal arteriole muscularization. RhoB, which was increased by hypoxia, was identified as one of the targets of miR-223. Overexpressed miR-223 suppressed RhoB and inhibited the consequent phosphorylation of myosin phosphatase target subunit (MYPT1) and the expression of myosin light chain of myosin II (MLC2), which was identified as another target of miR-223. Furthermore, serum miR-223 levels were decreased in female patients with PAH associated with congenital heart disease. Our study provides the first evidence that miR-223 can regulate PASMC proliferation, migration, and actomyosin reorganization through its novel targets, RhoB and MLC2, resulting in vascular remodeling and the development of PAH. It also highlights miR-223 as a potential circulating biomarker and a small molecule drug for diagnosis and treatment of PAH.

Cardiac-specific miRNA in cardiogenesis, heart function, and cardiac pathology (with focus on myocardial infarction)

Cardiac miRNAs (miR-1, miR133a, miR-208a/b, and miR-499) are abundantly expressed in the myocardium. They play a central role in cardiogenesis, heart function and pathology. While miR-1 and miR-133a predominantly control early stages of cardiogenesis supporting commitment of cardiac-specific muscle lineage from embryonic stem cells and mesodermal precursors, miR-208 and miR-499 are involved in the late cardiogenic stages mediating differentiation of cardioblasts to cardiomyocytes and fast/slow muscle fiber specification. In the heart, miR-1/133a control cardiac conductance and automaticity by regulating all phases of the cardiac action potential. miR-208/499 located in introns of the heavy chain myosin genes regulate expression of sarcomeric contractile proteins. In cardiac pathology including myocardial infarction (MI), expression of cardiac miRNAs is markedly altered that leads to deleterious effects associated with heart wounding, arrhythmia, increased apoptosis, fibrosis, hypertrophy, and tissue remodeling. In acute MI, circulating levels of cardiac miRNAs are significantly elevated making them to be a promising diagnostic marker for early diagnosis of acute MI. Great cardiospecific capacity of these miRNAs is very helpful for enhancing regenerative properties and survival of stem cell and cardiac progenitor transplants and for reprogramming of mature non-cardiac cells to cardiomyocytes.

microRNAs Databases: Developmental Methodologies, Structural and Functional Annotations

microRNA (miRNA) is an endogenous and evolutionary conserved non-coding RNA, involved in post-transcriptional process as gene repressor and mRNA cleavage through RNA-induced silencing complex (RISC) formation. In RISC, miRNA binds in complementary base pair with targeted mRNA along with Argonaut proteins complex, causes gene repression or endonucleolytic cleavage of mRNAs and results in many diseases and syndromes. After the discovery of miRNA lin-4 and let-7, subsequently large numbers of miRNAs were discovered by low-throughput and high-throughput experimental techniques along with computational process in various biological and metabolic processes. The miRNAs are important non-coding RNA for understanding the complex biological phenomena of organism because it controls the gene regulation. This paper reviews miRNA databases with structural and functional annotations developed by various researchers. These databases contain structural and functional information of animal, plant and virus miRNAs including miRNAs-associated diseases, stress resistance in plant, miRNAs take part in various biological processes, effect of miRNAs interaction on drugs and environment, effect of variance on miRNAs, miRNAs gene expression analysis, sequence of miRNAs, structure of miRNAs. This review focuses on the developmental methodology of miRNA databases such as computational tools and methods used for extraction of miRNAs annotation from different resources or through experiment. This study also discusses the efficiency of user interface design of every database along with current entry and annotations of miRNA (pathways, gene ontology, disease ontology, etc.). Here, an integrated schematic diagram of construction process for databases is also drawn along with tabular and graphical comparison of various types of entries in different databases. Aim of this paper is to present the importance of miRNAs-related resources at a single place.

Elevation of Circulating miR-210-3p in High-Altitude Hypoxic Environment

Background: The induction of miR-210-3p, a master hypoxamir, is a consistent feature of the hypoxic response in both normal and malignant cells. However, whether miR-210-3p acts as a circulating factor in response to a hypoxic environment remains unknown. The current study aimed to examine the effect of a high-altitude hypoxic environment on circulating miR-210-3p.

Methods: We examined and compared the levels of miR-210-3p using TaqMan-based qRT-PCR in both peripheral blood cells and plasma from 84 ethnic Chinese Tibetans residing at 3560 m, 46 newly arrived migrant Han Chinese (Tibet Han) and 82 Han Chinese residing at 8.9 m (Nanjing Han). Furthermore, we analyzed the correlations of miR-210-3p with hematological indices.

Results: The relative concentrations of miR-210-3p to internal reference U6 in blood cells were significantly higher in the Tibet Han group (1.01 ± 0.11, P < 0.001) and in the Tibetan group (1.17 ± 0.09, P < 0.001) than in the Nanjing Han group (0.51 ± 0.04). The absolute concentrations of plasma miR-210-3p were also markedly elevated in the Tibet Han group (503.54 ± 42.95 fmol/L, P = 0.004) and in the Tibetan group (557.78 ± 39.84 fmol/L, P < 0.001) compared to the Nanjing Han group (358.39 ± 16.16 fmol/L). However, in both blood cells and plasma, miR-210-3p levels were not significantly different between the Tibet Han group and the Tibetan group (P = 0.280, P = 0.620, respectively). Plasma miR-210-3p concentrations were positively correlated with miR-210-3p levels in blood cells (r = 0.192, P = 0.005). Furthermore, miR-210-3p levels in both blood cells and plasma showed strong positive correlations with red blood cell counts and hemoglobin and hematocrit values.

Conclusion: These data demonstrated, for the first time, that miR-210-3p might act as a circulating factor in response to hypoxic environments and could be associated with human adaptation to life at high altitudes.

A non-invasive method to determine the pluripotent status of stem cells by culture medium microRNA expression detection

To precisely determine the type and status of cells is an important prerequisite for basic researches and regenerative medicine involving stem cells or differentiated cells. However, the traditional destructive cell status examination methods have many limitations, mainly due to the heterogeneity of cells under the reprogramming or differentiation/trans-differentiation process. Here we present a new method to non-destructively determine the pluripotent level of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), or the types of differentiated cells. The method is achieved by examining the expression profiles of microRNAs (miRNAs) in cell culture medium, which show consistent abundance trend as those of the cellular miRNAs. Therefore, the method enables status examination and afterward application being achieved on the same population of cells, which will greatly facilitate cell reprogramming or differentiation/trans-differentiation related based research and clinical therapy.

The prognostic value of circulating microRNAs in heart failure: preliminary results from a genome-wide expression study

INTRODUCTION

Recent studies have demonstrated the potential of microRNAs (miRNA) as biomarkers in various cardiovascular disorders. The aim of the present study was to quantitatively evaluate the expression levels of miRNAs in patients with chronic congestive heart failure (CHF) in order to identify differential expression profiles as biomarkers with prognostic values.

MATERIALS AND METHOD

The study included 20 clinically stable [New York Heart Association (NYHA) II] and 22 decompensated (NYHA III and IV) CHF patients and 15 healthy controls. miRNA profiling was performed using a microarray method. Dysregulated miRNAs were evaluated for their biomarker potential.

RESULTS

Microarray profiling revealed an increase in the expression of miR-21, miR-650, miR-744, miR-516-5p, miR-1292, miR-182, miR-1228, miR-595, miR-663b, miR-1296, miR-1825, miR-299-3p, miR-662 miR-122, miR-3148 and miR-518e and a decrease in the expression of miR-129-3p, miR-3155, miR-3175, miR-583, miR-568, miR-30d, miR-200a-star, miR-1979, miR-371-3p, miR-155-star and miR-502-5p in sera of CHF patients. The prognostic value of miR-182 [area under the curve (AUC) 0.695] was found to be superior to pro-brain type natriuretic peptide (NT-proBNP; AUC 0.350) and high-sensitivity C-reactive protein (hs-CRP) (AUC 0.475) by receiver operator characteristic (ROC) analysis. Cox regression analysis showed that miR-182 could predict cardiovascular mortality (P = 0.032).

CONCLUSION

We demonstrated the increased expression levels of circulating miRNAs in CHF as compared with controls. Moreover, miR-182 was found to be a potential prognostic marker in CHF.

microRNAs with different functions and roles in disease development and as potential biomarkers of diabetes: progress and challenges

Biomarkers provide information on early detection of diseases, in determining individuals at risk of developing complications or subtyping individuals for disease phenotypes. In addition, biomarkers may lead to better treatment strategies, personalized therapy, and improved outcome. A major gap in the field of biomarker development is that we have not identified appropriate (minimally invasive, life-style independent and informative) biomarkers for the underlying disease process(es) that can be measured in readily accessible samples (e.g. serum, plasma, blood, urine). miRNAs function as regulators in wide ranging cellular and physiological functions and also participate in many physiopathological processes and thus have been linked to many diseases including diabetes, metabolic and cardiovascular diseases, cancer, neurodegenerative diseases, and autoimmunity. Many miRNAs have been shown to have predictive value as potential biomarkers in a variety of diseases including diabetes, which are detectable in some instances many years before the manifestation of disease. Although some technical challenges still remain, due to their availability in the circulation, relative stability, and ease of detection; miRNAs have emerged as a promising new class of biomarkers to provide information on early detection of disease, monitoring disease progression, in determining individual's risk of developing complications or subtyping individuals for disease phenotypes, and to monitor response to therapeutic interventions. As a final note, most of the miRNAs reported in the literature have not yet been validated in sufficiently powered and longitudinal studies for specificity for that particular disease.

Luteolin Inhibits Ischemia/Reperfusion-Induced Myocardial Injury in Rats via Downregulation of microRNA-208b-3p

BACKGROUND

Luteolin (LUT), a kind of flavonoid which is extracted from a variety of diets, has been reported to convey protective effects of various diseases. Recent researches have suggested that LUT can carry out cardioprotective effects during ischemia/reperfusion (I/R). However, there have no reports on whether LUT can exert protective effects against myocardial I/R injury through the actions of specific microRNAs (miRs). The purpose of this study was to determine which miRs and target genes LUT exerted such function through.

METHODS

Expression of various miRs in perfused rat hearts was detected using a gene chip. Target genes were predicted with TargetScan, MiRDB and MiRanda. Anoxia/reoxygenation was used to simulate I/R. Cells were transfected by miR-208b-3p mimic, inhibitor and small interfering RNA of Ets1 (avian erythroblastosis virus E26 (v ets) oncogene homolog 1). MiR-208b-3p and Ets1 mRNA were quantified by real-time quantitative polymerase chain reaction. The percentage of apoptotic cells was detected by annexin V-fluorescein isothiocyanate/propidium iodide dyeing and flow cytometry. The protein expression levels of cleaved caspase-3, Bcl-2, Bax, and Ets1 were examined by western blot analysis. A luciferase reporter assay was used to verify the combination between miR-208b-3p and the 3'-untranslated region of Ets1.

RESULTS

LUT pretreatment reduced miR-208b-3p expression in myocardial tissue, as compared to the I/R group. And LUT decreased miR-208b-3p expression and apoptosis caused by I/R. However, overexpression of miR-208b-3p further aggravated the changes caused by I/R and blocked all the effects of LUT. Knockdown of miR-208b-3p expression also attenuated apoptosis, while knockdown of Ets1 promoted apoptosis. Further, the luciferase reporter assay showed that miR-208b-3p could inhibit Ets1 expression.

CONCLUSION

LUT pretreatment conveys anti-apoptotic effects after myocardial I/R injury by decreasing miR-208b-3p and increasing Ets1 expression levels.

Circulating Extracellular microRNA in Systemic Autoimmunity

MicroRNAs (miRNAs) are differentially regulated in healthy, activated, inflamed, neoplastic, or otherwise pathological cells and tissues. While their main functions are executed intracellularly, many miRNAs can reproducibly be detected extracellularly in plasma and serum. This circulating, extracellular miRNA is protected against degradation by complexation with carrier proteins and/or by being enclosed in subcellular membrane vesicles. This, together with their tissue- and disease-specific expression, has fuelled the interest in using circulating microRNA profiles as harbingers of disease, i.e., as diagnostic analytes and as clues to dysregulated pathways in disease. Many studies show that inflammation and immune dysregulation, e.g., in autoimmune diseases, are associated with distinct miRNA expression changes in targeted tissues and in innate and adaptive immunity cells such as lymphocytes, natural killer cells, neutrophil granulocytes, and monocyte-macrophages. Exploratory studies (only validated in a few cases) also show that specific profiles of circulating miRNAs are associated with different systemic autoimmune diseases including systemic lupus erythematosus (SLE), systemic sclerosis, and rheumatoid arthritis. Even though the link between cellular alterations and extracellular profiles is still unpredictable, the data suggest that circulating miRNAs in autoimmunity may become diagnostically useful. Here, we review important circulating miRNAs in animal models of inflammation and in systemic autoimmunity and summarize some proposed functions of miRNAs in immune regulation and dysregulation. We conclude that the studies suggest new hypotheses and additional experiments, and that further diagnostic development is highly dependent on analytical method development and on obtaining sufficient numbers of uniformly processed samples from clinically well-characterized patients and controls.

The role of circulating miRNAs in multiple myeloma

Multiple myeloma (MM) is a common malignant hematological disease. Dysregulation of microRNAs (miRNAs) in MM cells and bone marrow microenviroment has important impacts on the initiation and progression of MM and drug resistance in MM cells. Recently, it was reported that MM patient serum and plasma contained sufficiently stable miRNA signatures, and circulating miRNAs could be identified and measured accurately from body fluid. Compared to conventional diagnostic parameters, the circulating miRNA profile is appropriate for the diagnosis of MM and estimates patient progression and therapeutic outcome with higher specificity and sensitivity. In this review, we mainly focus on the potential of circulating miRNAs as diagnostic, prognostic, and predictive biomarkers for MM and summarize the general strategies and methodologies for identification and measurement of circulating miRNAs in various cancers. Furthermore, we discuss the correlation between circulating miRNAs and the cytogenetic abnormalities and biochemical parameters assessed in multiple myeloma.

Profile of microRNA in Giant Panda Blood: A Resource for Immune-Related and Novel microRNAs

The giant panda (Ailuropoda melanoleuca) is one of the world's most beloved endangered mammals. Although the draft genome of this species had been assembled, little was known about the composition of its microRNAs (miRNAs) or their functional profiles. Recent studies demonstrated that changes in the expression of miRNAs are associated with immunity. In this study, miRNAs were extracted from the blood of four healthy giant pandas and sequenced by Illumina next generation sequencing technology. As determined by miRNA screening, a total of 276 conserved miRNAs and 51 novel putative miRNAs candidates were detected. After differential expression analysis, we noticed that the expressions of 7 miRNAs were significantly up-regulated in young giant pandas compared with that of adults. Moreover, 2 miRNAs were up-regulated in female giant pandas and 1 in the male individuals. Target gene prediction suggested that the miRNAs of giant panda might be relevant to the expressions of 4,602 downstream genes. Subseuqently, the predicted target genes were conducted to KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis and we found that these genes were mainly involved in host immunity, including the Ras signaling pathway, the PI3K-Akt signaling pathway, and the MAPK signaling pathway. In conclusion, our results provide the first miRNA profiles of giant panda blood, and the predicted functional analyses may open an avenue for further study of giant panda immunity.

Development and regulatory application of microRNA biomarkers

MicroRNAs, a class of regulatory small non-coding RNAs, are emerging as promising biomarkers for different health outcomes. Due to their tissue specificity, stability in extracellular space and high conservation between preclinical test species, applications of novel miRNA-based biomarkers for drug safety testing regarding hepatotoxicity and cardiotoxicity are investigated. Furthermore, miRNA expression is altered by environmental exposure such as cigarette smoke or polychlorinated biphenyls. As a consequence, miRNAs potentially influence tumor suppressor genes and oncogenes and may influence carcinogenesis. This has raised the interest in the use of miRNA profiles for health risk assessment. This review summarizes the recent developments in miRNA research with focus on biomarkers for drug safety testing and biomarkers for health outcomes related to environmental exposures.

microRNAs as pharmacogenomic biomarkers for drug efficacy and drug safety assessment

Much evidence has documented that microRNAs (miRNAs) play an important role in the modulation of interindividual variability in the production of drug metabolizing enzymes and transporters (DMETs) and nuclear receptors (NRs) through multidirectional interactions involving environmental stimuli/stressors, the expression of miRNA molecules and genetic polymorphisms. MiRNA expression has been reported to be affected by drugs and miRNAs themselves may affect drug metabolism and toxicity. In cancer research, miRNA biomarkers have been identified to mediate intrinsic and acquired resistance to cancer therapies. In drug safety assessment, miRNAs have been found associated with cardiotoxicity, hepatotoxicity and nephrotoxicity. This review article summarizes published studies to show that miRNAs can serve as early biomarkers for the evaluation of drug efficacy and drug safety.

Translating extracellular microRNA into clinical biomarkers for drug-induced toxicity: from high-throughput profiling to validation

Over the past 5 years, extracellular microRNAs (miRNAs) are being vigorously explored as injury biomarkers, including drug-induced cardiotoxicity, hepatotoxicity and nephrotoxicity. Currently, the development of miRNAs as clinical biomarkers has been hindered by the lack of standardization. Therefore, extracellular miRNA-based biomarkers have not been embraced as diagnostic tools. Each platform has its strengths and weaknesses when working with low-input-amount RNA samples from body fluids; the selection of a miRNA quantification approach should be based on the study design. The following review provides a summary of the extracellular miRNA release and stability in body fluids, performances of different miRNA quantification platforms, existing clinical gold standards for drug-induced tissue damage and translation of the miRNA biomarkers from the nonclinical to clinical setting.

MicroRNAs in placental health and disease

MicroRNAs (miRNAs) constitute a large family of small noncoding RNAs that are encoded by the genomes of most organisms. They regulate gene expression through posttranscriptional mechanisms to attenuate protein output in various genetic networks. The discovery of miRNAs has transformed our understanding of gene regulation and sparked intense efforts intended to harness their potential as diagnostic markers and therapeutic tools. Over the last decade, a flurry of studies has shed light on placental miRNAs but has also raised many questions regarding the scope of their biologic action. Moreover, the recognition that miRNAs of placental origin are released continually in the maternal circulation throughout pregnancy suggested that circulating miRNAs might serve as biomarkers for placental function during pregnancy. Although this generated much enthusiasm, recently recognized challenges have delayed the application of miRNA-based biomarkers and therapeutics in clinical practice. In this review, we summarize key findings in the field and discuss current knowledge related to miRNAs in the context of placental biology.

Cardiovascular and Cerebrovascular Disease Associated microRNAs Are Dysregulated in Placental Tissues Affected with Gestational Hypertension, Preeclampsia and Intrauterine Growth Restriction

Aims

To demonstrate that pregnancy-related complications are associated with alterations in cardiovascular and cerebrovascular microRNA expression. Gene expression of 32 microRNAs (miR-1-3p, miR-16-5p, miR-17-5p, miR-20a-5p, miR-20b-5p, miR-21-5p, miR-23a-3p, miR-24-3p, miR-26a-5p, miR-29a-3p, miR-33a-5p, miR-92a-3p, miR-100-5p, miR-103a-3p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-130b-3p, miR-133a-3p, miR-143-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-181a-5p, miR-195-5p, miR-199a-5p, miR-208a-3p, miR-210-3p, miR-221-3p, miR-342-3p, miR-499a-5p, and miR-574-3p) was assessed in placental tissues, compared between groups (35 gestational hypertension, 80 preeclampsia, 35 intrauterine growth restriction and 20 normal pregnancies) and correlated with the severity of the disease with respect to clinical signs, delivery date, and Doppler ultrasound parameters. Initially, selection and validation of endogenous controls for microRNA expression studies in placental tissues affected by pregnancy-related complications have been carried out.

Results

The expression profile of microRNAs was different between pregnancy-related complications and controls. The up-regulation of miR-499a-5p was a common phenomenon shared between gestational hypertension, preeclampsia, and intrauterine growth restriction. Preeclamptic pregnancies delivering after 34 weeks of gestation and IUGR with abnormal values of flow rate in the umbilical artery demonstrated up-regulation of miR-1-3b. Preeclampsia and IUGR requiring termination of gestation before 34 weeks of gestation were associated with down-regulation of miR-26a-5p, miR-103a-3p and miR-145-5p. On the other hand, some of microRNAs (miR-16-5p, miR-100-5p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-143-3p, miR-195-5p, miR-199a-5p, miR-221-3p, miR-342-3p, and miR-574-3p) were only down-regulated or showed a trend to down-regulation just in intrauterine growth restriction pregnancies requiring the delivery before 34 weeks of gestation.

Conclusion

Epigenetic changes induced by pregnancy-related complications in placental tissue may cause later onset of cardiovascular and cerebrovascular diseases in offspring.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

The biology of circulating microRNAs in cardiovascular disease

BACKGROUND

Since their first description in mammalian cells, more than 2500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins.

MATERIALS AND METHODS

We will discuss recent data regarding circulating microRNAs, their potential role as novel biomarkers and intercellular communicators, as well as future challenges of studying and applying such novel biology, particularly in the cardiovascular system.

RESULTS

Circulating microRNAs have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In addition, therapeutic application of extracellular microRNAs has also been explored.

CONCLUSION

Over recent years, increasing attention has been paid to the role of circulating miRNAs in cardiovascular disease. As biomarkers and intercellular communicators, circulating miRNAs could play important roles in the prediction, diagnosis and tailored treatment of cardiovascular diseases in the near future.

Effect of microRNA-208a on mitochondrial apoptosis of cardiomyocytes of neonatal rats

OBJECTIVE

To explore the effect and mechanism of microRNA-208a (miR-208a) in the mitochondrial apoptosis of cardiomyocytes of neonatal rats.

METHODS

The primary cultured cardiomyocytes of neonatal rats were added into the hypoxia incubator for the hypoxia induction. The overexpression system for miR-208a of cardiomyocytes of neonatal rats was built. The flow cytometry assay was employed to detect the incidence of apoptosis in the over-expressed miR-208a. The mitochondrial staining technique was used to detect the change in the mitochondrial morphology of over-expressed miR-208a. The bioinformatic analysis was chosen to analyze and predict the target gene of miR-208a.

RESULTS

Firstly, the primary culture system of cardiomyocytes of neonatal rats was successfully built. The miR-208a was over-expressed in cardiomyocytes of neonatal rats by miR-208a Mimics. Results of flow cytometry assay showed that the over-expressed miR-208a could significantly reduce the incidence of apoptosis; while results of mitochondrial staining indicated the change in the mitochondrial morphology of over-expressed miR-208a and the mitochondrial fission process was inhibited. In conclusion, it was supposed that miR-208a could inhibit the activation of mitochondrial fission process to keep the cardiomyocytes from apoptosis.

CONCLUSIONS

The over-expressed miR-208a can reduce the incidence of apoptosis in the cardiomyocytes of neonatal rats, significantly change the mitochondrial morphology and inhibit the mitochondrial fission process.

Disorders of MicroRNAs in Peripheral Blood Mononuclear Cells: As Novel Biomarkers of Ankylosing Spondylitis and Provocative Therapeutic Targets

Background. MicroRNAs can potentially regulate every aspect of cellular activity. In this study, we investigated whether AS pathogenesis involves microRNAs disorders. Result. The expression of 2 microRNAs, hsa-miR-126-3p and hsa-miR-29a, was significantly lower in active AS group before etanercept therapy than in control group. Marched fold changes of them were 3.76 and 16.22. Moreover, expressions of hsa-miR-126-3p and hsa-miR-29a were dramatically upregulated after 12-weeks etanercept treatment. Fold changes were 2.20 and 3.18. All regulations of microRNAs expression mentioned before were statistically significant (fold change >2 and P < 0.05). The expression disorders of the 2 microRNAs did not statistically significantly correlated with BASDAI, CRP, and ESR. Conclusion. AS pathogenesis involved dysregulation of microRNAs. Hsa-miR-126-3p and hsa-miR-29a will probably become the potential biomarkers and provocative therapeutic targets of AS.

The mesmiRizing complexity of microRNAs for striated muscle tissue engineering

microRNAs (miRs) are small non-protein-coding RNAs, able to post-transcriptionally regulate many genes and exert pleiotropic effects. Alteration of miR levels in tissues and in the circulation has been associated with various pathological and regenerative conditions. In this regard, tissue engineering of cardiac and skeletal muscles is a fascinating context for harnessing the complexity of miR-based circuitries and signals. In this review, we will focus on miR-driven regulation of cardiac and skeletal myogenic routes in homeostatic and challenging states. Furthermore, we will survey the intriguing perspective of exosomal and circulating miRs as novel paracrine players, potentially useful for current and future approaches of regenerative medicine for the striated muscles.

miRNA therapeutics in cardiovascular diseases: promises and problems

microRNAs (miRNAs) are a novel class of non-coding RNAs which found their way into the clinic due to their fundamental roles in cellular processes such as differentiation, proliferation, and apoptosis. Recently, miRNAs have been known as micromodulators in cellular communications being involved in cell signaling and microenvironment remodeling. In this review, we will focus on the role of miRNAs in cardiovascular diseases (CVDs) and their reliability as diagnostic and therapeutic biomarkers in these conditions. CVDs comprise a variety of blood vessels and heart disorders with a high rate of morbidity and mortality worldwide. This necessitates introduction of novel molecular biomarkers for early detection, prevention, or treatment of these diseases. miRNAs, due to their stability, tissue-specific expression pattern and secretion to the corresponding body fluids, are attractive targets for cardiovascular-associated therapeutics. Explaining the challenges ahead of miRNA-based therapies, we will discuss the exosomes as delivery packages for miRNA drugs and promising novel strategies for the future of miRNA-based therapeutics. These approaches provide insights to the future of personalized medicine for the treatment of CVDs.