Function and regulation of microRNA-31 in development and disease

MiR-31-5p acts as a tumor suppressor in renal cell carcinoma by targeting cyclin-dependent kinase 1 (CDK1)

BACKGROUND

Renal cell carcinoma (RCC) accounts for more than 90% of cancers in the kidney. RCC is often asymptomatic, as a result people with RCC generally have advanced disease by the time it is discovered and has a poor prognosis compared to other cancers. Therefore, it is necessary to explore its pathogenesis and identify some reliable prognostic biomarker of RCC. miRNAs are emerging as important players in the development and progression of RCC. miR-31-5p has been reported to act as a tumor suppressor in hepatocellular carcinoma (HCC). The aim of this study is to determine the detailed molecular mechanism of miR-31-5p in the progression of RCC and to investigate its potential clinical value.

METHODS

In this study, RT-qPCR, EdU assay, CCK-8 assay, wound scratch assay, transwell assay, flow cytometry assay and cell cycle assay were performed to detect miR-31-5p expression and its functions in RCC. Moreover, 42 formalin-fixed paraffin-embedded (FFPE) RCC samples were used to analyze the relationship between miR-31-5p expression and patients' overall survival. Finally, luciferase reporter assay, RT-qPCR assay and western blot were used to explore the association between miR-31-5p and its potential targets.

RESULTS

miR-31-5p was significantly down-regulated in RCC tissues and RCC cell lines compared with paired adjacent normal tissues and normal cell lines. miR-31-5p downregulation was associated with poor prognosis in RCC patients. Overexpression of miR-31-5p inhibited RCC cell proliferation, migration and invasion and cell cycle. Conversely, down-regulation of miR-31-5p promoted cell proliferation, migration and invasion. Furthermore, cyclin-dependent kinasec1 (CDK1), a key player in cell cycle regulation, was identified as a functional target of miR-31-5p.

CONCLUSIONS

Our results suggest that miR-31-5p serves as a tumor suppressor in RCC and is expected to be a molecular biomarker for poor prognosis of RCC.

Understanding psoriasis: Role of miRNAs

Psoriasis is a chronic, immune-mediated inflammatory skin disease, with a multifactorial etiology and important immunologic, genetic and environmental components. Psoriasis vulgaris represents its most common form, with a variable prevalence across the globe. Although its pathogenesis remains to be fully elucidated, a lack of balance in the epigenetic network has been shown to trigger certain elements of this disease, possibly altering its outcome. MicroRNAs are small non-coding RNA molecules involved in RNA-silencing and the post-transcriptional regulation of gene expression, which also appear to mediate the immune dysfunction in psoriasis. Although microRNA research is a new field in dermatology and psoriasis, there is rapidly accumulating evidence for its major contribution in the pathogenesis of chronic inflammatory conditions, including psoriasis and other dermatological disorders. Furthermore, circulating miRNAs identified in patients' blood samples have been identified as promising biomarkers of diagnosis, prognosis or treatment response. Extended investigations in this field are required, as until now, the exact involvement of miRNAs in psoriasis have remained to be entirely elucidated. This short review highlights a number of the roles of miRNAs found in different stages of psoriasis.

Levels of miR-31 and its target genes in dermal mesenchymal cells of patients with psoriasis

BACKGROUND

Psoriasis is characterized by chronic inflammatory dermatosis, and the pathogenesis of psoriasis is associated with mesenchymal stem cells (MSCs) and deregulation of the expression of miR-31. This study aimed to clarify the function of miR-31 in dermal MSCs (DMSCs) in the pathogenesis of psoriasis.

METHODS

The expression of miR-31 was assayed by a microarray and that of target genes of miR-31 was tested by quantitative PCR.

RESULTS

The expression of miR-31 in the psoriasis group was 0.2677 folds that of the control group. The expression of EMP1 and EIG121L genes, whose products are located on the cell membrane, in the psoriasis group was 4.095579 and 5.367017 folds that in the control group, respectively. The expression of GRB10, PTPN14, QKI, RNF144B, and TACC2 genes, whose products are located in the cytoplasm, in the psoriasis group was 1.440428, 1.198335, 1.737285, 7.379546, and 1.531947 folds that of the control. The expression of PRELP, whose products are secreted in the extracellular space, in the psoriasis group was 1.351684 folds that of the control. The expression of RBMS1, KHDRBS3, and SATB2, whose products play a role in the nucleus, in the psoriasis group was 2.237199, 1.277159, and 1.005742 folds that of the control, respectively.

CONCLUSIONS

Our results suggest that the low expression of miR-31 in DMSCs in patients with psoriasis causes an increase in the expression of some of its target genes, which in turn facilitates T lymphocyte activation by inhibiting the proliferation of DMSCs and therefore participates in the pathogenesis of psoriasis.

miREM: an expectation-maximization approach for prioritizing miRNAs associated with gene-set

Background

The knowledge of miRNAs regulating the expression of sets of mRNAs has led to novel insights into numerous and diverse cellular mechanisms. While a single miRNA may regulate many genes, one gene can be regulated by multiple miRNAs, presenting a complex relationship to model for accurate predictions.

Results

Here, we introduce miREM, a program that couples an expectation-maximization (EM) algorithm to the common approach of hypergeometric probability (HP), which improves the prediction and prioritization of miRNAs from gene-sets of interest. miREM has been made available through a web-server (https://bioinfo-csi.nus.edu.sg/mirem2/) that can be accessed through an intuitive graphical user interface. The program incorporates a large compendium of human/mouse miRNA-target prediction databases to enhance prediction. Users may upload their genes of interest in various formats as an input and select whether to consider non-conserved miRNAs, amongst filtering options. Results are reported in a rich graphical interface that allows users to: (i) prioritize predicted miRNAs through a scatterplot of HP p-values and EM scores; (ii) visualize the predicted miRNAs and corresponding genes through a heatmap; and (iii) identify and filter homologous or duplicated predictions by clustering them according to their seed sequences.

Conclusion

We tested miREM using RNAseq datasets from two single “spiked” knock-in miRNA experiments and two double knock-out miRNA experiments. miREM predicted these manipulated miRNAs as having high EM scores from the gene set signatures (i.e. top predictions for single knock-in and double knock-out miRNA experiments). Finally, we have demonstrated that miREM predictions are either similar or better than results provided by existing programs.

Electronic supplementary material

The online version of this article (10.1186/s12859-018-2292-1) contains supplementary material, which is available to authorized users.

Role of miR-31 and SATB2 in arsenic-induced malignant BEAS-2B cell transformation

Arsenic is a naturally occurring and highly potent metalloid known to elicit serious public health concerns. Today, approximately 200 million people around the globe are exposed to arsenic-contaminated drinking water at levels greater than the World Health Organization's recommended limit of 10 parts per billion. As a class I human carcinogen, arsenic exposure is known to elicit various cancers, including lung, skin, liver, and kidney. Current evidence suggests that arsenic is capable of inducing both genotoxic and cytotoxic injury, as well as activating epigenetic pathways to induce carcinogenesis. Our study identifies a novel pathway that is implicated in arsenic-induced carcinogenesis. Arsenic down-regulated miRNA-31 and the release of this inhibition caused overexpression of special AT-rich sequence-binding protein 2 (SATB2). Arsenic is known to disrupt miRNA expression, and here we report for the first time that arsenic is capable of inhibiting miR-31 expression. As a direct downstream target of miR-31, SATB2 is a prominent transcription factor, and nuclear matrix binding protein implicated in many types of human diseases including lung cancer. Results from this study show that arsenic induces the overexpressing SATB2 by inhibiting miR-31 expression, which blocks the translation of SATB2 mRNA, since levels of SATB2 mRNA remain the same but protein levels decrease. Overexpression of SATB2 induces malignant transformation of human bronchial epithelial (BEAS-2B) cells indicating the importance of the expression of miR-31 in preventing carcinogenesis by suppressing SATB2 protein levels.

Histone Deacetylase-3 Modification of MicroRNA-31 Promotes Cell Proliferation and Aerobic Glycolysis in Breast Cancer and Is Predictive of Poor Prognosis

Purpose

The incidence and mortality of breast cancer is increasing worldwide. There is a constant quest to understand the underlying molecular biology of breast cancer so as to plan better treatment options. The purpose of the current study was to characterize the expression of histone deacetylases-3 (HDAC3), a member of class I HDACs, and assess the clinical significance of HDAC3 in breast cancer.

Methods

Quantitative real-time polymerase chain reaction, immunohistochemistry, and western blot analysis were used to examine messenger RNA and protein expression levels. The relationships between HDAC3 expression and clinicopathological variables were analyzed. MTT assays were used to detect cell proliferation. Glucose-uptake, lactate, adenosine triphosphate, and lactate dehydrogenase assays were employed to detect aerobic glycolysis. Chromatin immunoprecipitation was used to detect microRNA-31 (miR-31) promoter binding.

Results

Our data revealed that HDAC3 was upregulated in breast cancer tissue compared with matched para-carcinoma tissues, and high levels of HDAC3 were positively correlated with advanced TNM stage and N stage of cancer. Furthermore, overexpression of HDAC3 promoted breast cancer cell-proliferation and aerobic glycolysis. The functional involvement of HDAC3 was related in part to the repression of miR-31 transcription via decreased histone H3 acetylation at lysine K9 levels of the miR-31 promoter. Survival analysis revealed that the level of HDAC3 was an independent prognostic factor for breast cancer patients.

Conclusion

Our findings revealed that HDAC3 served as an oncogene that could promote cell proliferation and aerobic glycolysis and was predictive of a poor prognosis in breast cancer. HDAC3 participated in the cell proliferation of breast cancer, which may prove to be a pivotal epigenetic target against this devastating disease.

Circulating miR-31 as an effective biomarker for detection and prognosis of human cancer: a meta-analysis

PURPOSE

Circulating miR-31 was found to be associated with cancers detection and prognosis. The present meta-analysis aimed to explore the effect of circulating miR-31 on cancer detection and prognosis.

METHOD

The studies were accessed using multiple databases. RevMan5.3, Meta-DiSc 1.4, and STATA14.0 were used to estimate the pooled effects, heterogeneity among studies, and publication bias.

RESULTS

A total of 14 studies with 1397 cancer patients and 1039 controls were included. For the 12 prognostic tests, the adjusted pooled-AUC was 0.79 (95% CI: 0.73-0.86) as the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd ratio (DOR) from 10 tests was 0.79 (95% CI: 0.76-0.82), 0.79 (95% CI: 0.76-0.82), 3.81 (95% CI: 2.90-5.01), 0.26 (95% CI: 0.20-0.35), and 16.81 (95% CI: 9.67-29.25), respectively. For the 5 prognosis analyses, the pooled HR (hazard ratio) of overall survival (OS) was 1.55 (95% CI 1.30-1.86) for high versus low circulating miR-31 expression. However, high expression of circulating miR-31 did not significantly increase the risk of poor differentiation (pooled OR=1.39, 95% CI: 0.56-3.47) and LNM (pooled OR=3.46, 95% CI: 0.96-12.42) in lung cancer.

CONCLUSION

Circulating miR-31 is an effective biomarker and could be used as a component of miRs signature for cancer detection and prognosis surveillance.

MicroRNA-31 Function as a Suppressor Was Regulated by Epigenetic Mechanisms in Gastric Cancer

Gastric cancer is one of the most lethal malignancies worldwide. The aberrant expression of microRNA-31 (miR-31) has been reported in gastric cancer; however, its regulation mechanisms are still unclear. Here, we confirmed that miR-31 expression was significantly decreased in gastric cancer tissue and cell lines. Ectopic expression of miR-31 potentially suppresses proliferation and induced early apoptosis in gastric cancer cells. Furthermore, miR-31 expression was regulated as a result of epigenetic mechanisms. The downregulation of miR-31 was associated with promoter DNA methylation status in gastric cancer and cell lines. Moreover, we found that HDAC2 was the direct target of miR-31 by binding to 3′-UTR from the results of luciferase reporter assays, qRT-PCR, and western blotting. HDAC2 played an activation role in tumor growth, whose expression is upregulated and inversely associated with miR-31 levels. All the results suggested that miR-31 function as a crucial tumor suppressor was regulated by epigenetic mechanisms in gastric cancer. We found an epigenetic pathway loop, DNA methylation-miRNA expression-target gene-tumor progression in gastric cancer, and also provided implications for molecular diagnosis and therapeutics of gastric malignancies by detecting miR-31 as a potential target.

miR-31 and miR-145 as Potential Non-Invasive Regulatory Biomarkers in Patients with Endometriosis

Objective

Endometriosis is a prevalent gynecologic disease affecting 10% of women in reproductive age. Endometriosis is diagnosed by laparoscopy that was followed by histologic confirmation. Early diagnosis will lead to a more effective treatment with much less morbidity. As miR-31 and miR-145 are shown to be directly or indirectly correlated to biological processes involved in endometriosis, the aim of this study was to examine the association of miR-31 and miR-145 expression in plasma with the presence of endometriosis.

Materials and Methods

In this case control study, the plasma samples of 55 patients with endometriosis and 23 women without endometriosis were collected, extracted and analyzed by real time quantitative polymerase chain reaction (qPCR) for the expression of miR-145 and miR-31.

Results

Our findings showed that miR-31 expression levels in stage 3 or 4 and stage 1 or 2 were significantly down- regulated (less than 0.01-fold, P<0.05), while the expression level of miR-145 was significantly up-regulated in women with endometriosis in stage 1 or 2.

Conclusion

Different cellular biological processes, such as differentiation, proliferation, mitochondrial function, reactive oxygen species (ROS) production, invasion and decidualization, are deregulated in endometriosis. miR-31 and miR-145 are microRNAs (miRNAs) with potential roles, as shown in pathologies like cancers. We found that miR- 31 was under-expressed in patients with endometriosis, while miR-145 was over-expressed in stage 1 or 2, indicating that they were relatively down-regulated in the more severe forms. Our findings suggested that these two miRNAs may be considered as potential biomarkers with probable implications in early diagnosis and even follow-up of patients with endometriosis.

PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Postnatal reproductive development and the lactocrine hypothesis

Maternal effects on development can program cell fate and dictate offspring phenotype. Such effects do not end at birth, but extend into postnatal life through signals communicated from mother to offspring in first milk (colostrum). Transmission of bioactive factors from mother to offspring as a specific consequence of nursing defines a lactocrine mechanism. The female reproductive tract is not fully formed at birth (postnatal day = PND 0). Data for ungulates and mice indicate that disruption of development during neonatal life can have lasting effects on the form and function of uterine tissues. Uterine growth and histogenesis proceed in an ovary-independent manner shortly after birth, suggesting that extra-ovarian inputs are important in this process. Data for the pig indicate that lactocrine signals communicated within 12 to 48 h from birth constitute one source of such uterotrophic support. Disruption of lactocrine signaling, either naturally, by limited colostrum consumption, or experimentally, by milk replacer feeding, alters neonatal porcine uterine development and can have negative consequences for reproductive performance in adults. Substantial differences in endometrial and uterine gene expression between colostrum- and replacer-fed gilts were evident by PND 2, when RNA sequencing revealed over 800 differentially expressed, lactocrine-sensitive genes. Lactocrine-sensitive biological processes identified through transcriptomic studies and integrated microRNA-mRNA pathway analyses included those associated with both cell-cell and ESR1 signaling, and tissue development. Evidence for the pig indicates that colostrum consumption and lactocrine signaling are required to establish a normal uterine developmental program and optimal uterine developmental trajectory.

Overexpression of miR-31 in Peripheral Blood Mononuclear Cells (PBMC) from Patients with Ankylosing Spondylitis

Background

miRNAs play vital roles in regulating immunologic functions and autoimmunity. However, the levels of miR-31, miR-155, miR-16, and miR-181a have not been explored in AS, but were verified to play vital roles in other immunological diseases. The aim of our study was to examine whether the expressions of miR-31, miR-155, miR-16, and miR-181a are abnormal in AS.

Material/Methods

Real-time transcription-polymerase chain reaction analysis (RT-PCR) was used to determine the expression of miR-31, miR-155, miR-16, and miR-181a in peripheral blood mononuclear cells (PBMC) from 40 patients with AS and 40 healthy controls.

Results

The expression of miR-31 was increased in AS patients compared with healthy controls (p=0.001). Furthermore, we detected no significant differences in the expressions of miR-155, miR-16, and miR-181a between AS patients and healthy controls. However, the expression levels of the 4 miRNAs were all significantly different between less active AS and more active AS, with higher levels in more active AS. Moreover, no significant correlations were found between the 4 miRNAs levels with the clinical characteristics in the patients with AS. Interestingly, the expression levels of miR-31, miR-155, and miR-16 in PBMCs were significantly positively correlated with the ESR in new AS patients but not old AS patients.

Conclusions

Our results suggest that miR-31 is overexpressed in PBMCs of AS patients. Furthermore, miR-31, miR-155, miR-16 and miR-181a may be associated with AS disease activity.

Signal Transmission of Biological Reaction-Diffusion System by Using Synchronization

Molecular signal transmission in cell is very crucial for information exchange. How to understand its transmission mechanism has attracted many researchers. In this paper, we prove that signal transmission problem between neural tumor molecules and drug molecules can be achieved by synchronous control. To achieve our purpose, we derive the Fokker-Plank equation by using the Langevin equation and theory of random walk, this is a model which can express the concentration change of neural tumor molecules. Second, according to the biological character that vesicles in cell can be combined with cell membrane to release the cargo which plays a role of signal transmission, we preliminarily analyzed the mechanism of tumor-drug molecular interaction. Third, we propose the view of synchronous control which means the process of vesicle docking with their target membrane is a synchronization process, and we can achieve the precise treatment of disease by using synchronous control. We believe this synchronous control mechanism is reasonable and two examples are given to illustrate the correctness of our results obtained in this paper.

Roles of miR-31 and endothelin-1 in psoriasis vulgaris: pathophysiological functions and potential biomarkers

Psoriatic lesions are characterized by hyperproliferation, aberrant differentiation of keratinocytes resistant to apoptosis and inflammation. miR-31 plays pro-proliferative, pro-differentiative and pro-inflammatory roles and modulates apoptosis in psoriatic keratinocytes. Endothelin-1 (ET-1) is produced by psoriatic keratinocytes and suppresses apoptosis. Inflammation increases the production of ET-1, which in turn leads to the chronic stimulation of keratinocyte proliferation. The aim of this study was to identify the putative link between two potential biomarkers (miR-31 and ET-1) in patients with psoriasis. The study design included experimental group (29 patients with psoriasis), and the control group (22 blood donors). The PASI score evaluated the state of the disease (median: 18.6; interquartile range 14.5-20.9). Both, the serum level of ET-1 and the whole blood level of miR-31 were significantly increased (p<0.001 and p<0.05, respectively) in patients compared to the controls. However, a significant negative relationship between ET-1 and miR-31 was observed (Spearman's rho=-037, p=0.05). It is possible that a negative feedback loop will be present between miR-31 and ET-1. Our results indicate that miR-31 and ET-1, potential biomarkers of the disease, play significant roles in the pathophysiology of psoriasis.

Conditional knockout of microRNA-31 promotes the development of colitis associated cancer

MicroRNA-31 (miR-31) is an evolutionarily conserved microRNA, and its biological function in colorectal cancer and other cancers is controversial. In this study, we identified the host gene of mouse miR-31 and found that miR-31 was over-expressed in both human colorectal cancer and mouse colon cancer models. We here developed a miR-31 conditional knockout mouse model that allows for colon epithelium specific deletion of miR-31 to investigate its functionality in colon cancer development. We demonstrated that mice with miR-31 conditional deletion resulted in more severe colitis-associated cancer than wild-type, and we further identified Wdr5 as an important target of miR-31.

Changes in high-density lipoprotein-carried miRNA contribution to the plasmatic pool after consumption of dietary trans fat in healthy men

AIM

High-density lipoproteins (HDLs) are associated to cardioprotection and transport functional miRNAs in circulation. The aim of this study is to assess whether consumption of trans fatty acids (TFAs) modifies the HDL-carried miRNA concentration and their contribution to the plasmatic pool.

METHODS

In a double-blind, randomized crossover controlled study, nine healthy men were fed each of three isoenergetic 4-week diets: first, rich in industrial TFAs; second, rich in TFAs from ruminants; third, low in TFAs. miRNAs were extracted from plasma and purified HDLs, and quantified by the real-time quantitative PCR (n = 87).

RESULTS

Seven HDL-carried miRNAs contributed to more than 15% of the plasmatic pool. Although no significant difference in HDL-carried miRNA concentration among diets was observed after adjustment for multiple testing, changes in the contribution to the plasmatic pool between diets were observed for miR-124-3p, miR-375, miR-150-5p and miR-31-5p (p _FDR < 0.05). These miRNAs were enriched in lipid metabolism pathways.

CONCLUSION

These microtranscriptomic variants might reflect physiological changes in HDL functions in response to diet.

miR-31 Links Lipid Metabolism and Cell Apoptosis in Bacteria-Challenged Apostichopus japonicus via Targeting CTRP9

The biological functions of microRNAs (miRNAs) have been studied in a number of eukaryotic species. Recent studies on vertebrate animals have demonstrated critical roles of miRNA in immune and metabolic activities. However, studies on the functions of miRNA in invertebrates are very limited. Here, we demonstrated that miR-31 from Apostichopus japonicus disrupts the balance of lipid metabolism, thus resulting in cell apoptosis by targeting complement C1q tumor necrosis factor-related protein 9 (AjCTRP9), a novel adipokine with pleiotropic functions in immunity and metabolism. Lipidomic analysis suggested that the intercellular lipid metabolites were markedly altered, and three ceramide (Cer) species synchronously increased in the AjCTRP9-silenced coelomocytes. Moreover, exogenous Cer exposure significantly induced apoptosis in the coelomocytes in vivo, in agreement with findings from miR-31 mimic- or AjCTRP9 small-interfering RNA-transfected coelomocytes. Furthermore, we found that the imbalance in sphingolipid metabolism triggered by the overproduction of Cers ultimately resulted in the activation of the apoptosis initiator caspase-8 and executioner caspase-3. Our findings provide the first direct evidence that miR-31 negatively modulates the expression of AjCTRP9 and disturbance of Cer channels, thus leading to caspase-3- and caspase-8-dependent apoptosis, during the interactions between pathogens and host.

Minicircle-oriP-miR-31 as a Novel EBNA1-Specific miRNA Therapy Approach for Nasopharyngeal Carcinoma

MicroRNAs (miRNAs) are important post-transcriptional regulators that control cancer development and progression. However, the application of miRNA therapy in cancer has been hampered by a lack of an efficient and targeted delivery system. In our previous studies, an oriP promoter-based minicircle system successfully mediated targeted foreign gene expression in EBNA1-positive nasopharyngeal carcinoma (NPC). However, it remains to be evaluated whether this system can be applied for tumor miRNA therapy. miR-31-5p, a tumor suppressive miRNA involved in the tumorigenesis of EBV-positive NPC, was selected as the therapeutic miRNA to be transferred. In this work, we constructed a novel EBNA1-specific miRNA expression system, minicircle-oriP-miR-31. The results indicated that mc-oriP-miR-31 mediated selective miR-31-5p expression in EBNA1-positive NPC cells. Both the proliferation and migration of EBNA1-positive NPC cell lines were inhibited by mc-oriP-miR-31 treatment in vitro. Furthermore, mc-oriP-miR-31 treatment inhibited xenograft growth and lung metastasis in vivo. We also identified WDR5 as a novel miR-31-5p target. Knockdown of WDR5 inhibited NPC cell proliferation and migration and was associated with downregulation of Notch1. Reintroduction of WDR5 partially abrogated the suppressive effects induced by miR-31-5p. In conclusion, we demonstrate for the first time that targeted expression of miR-31-5p using a nonviral minicircle vector can serve as a novel approach for tumor miRNA therapy. Moreover, WDR5 may be a promising therapeutic target for NPC treatment.

Modulating microRNAs in cardiac surgery patients: Novel therapeutic opportunities?

This review focuses on microRNAs (miRs) in cardiac surgery, where they are emerging as potential targets for therapeutic intervention as well as novel clinical biomarkers. Identification of the up/down-regulation of specific miRs in defined groups of cardiac surgery patients can lead to the development of novel strategies for targeted treatment in order to maximise therapeutic results and minimise acute, delayed or chronic complications. MiRs could also be involved in determining the outcome independently of complications, for example in relation to myocardial perfusion and fibrosis. Because of their relevance in disease, their known sequence and pharmacological properties, miRs are attractive candidates for therapeutic manipulation. Pharmacological inhibition of individual miRs can be achieved by modified antisense oligonucleotides, referred to as antimiRs, while miR replacement can be achieved by miR mimics to increase the level of a specific miR. MiR mimics can restore the function of a lost or down-regulated miR, while antimiRs can inhibit the levels of disease-driving or aberrantly expressed miRs, thus de-repressing the expression of mRNAs targeted by the miR. The main delivery methods for miR therapeutics involve lipid-based vehicles, viral systems, cationic polymers, and intravenous or local injection of an antagomiR. Local delivery is particularly desirable for miR therapeutics and options include the development of devices specific for local delivery, light-induced antimiR, and vesicle-encapsulated miRs serving as therapeutic delivery agents able to improve intracellular uptake. Here, we discuss the potential therapeutic use of miRNAs in the context of cardiac surgery.