MicroRNA expression is differentially altered by xenobiotic drugs in different human cell lines

Potential Phytochemicals for Prevention of Familial Breast Cancer with BRCA Mutations

Breast cancer has remained a global challenge and the second leading cause of cancer mortality in women and family history. Hereditary factors are some of the major risk factors associated with breast cancer. Out of total breast cancer cases, 5-10% account only for familial breast cancer, and nearly 50% of all hereditary breast cancer are due to BRCA1/BRCA2 germline mutations. BRCA1/2 mutations play an important role not only in determining the clinical prognosis of breast cancer but also in the survival curves. Since this risk factor is known, a significant amount of the healthcare burden can be reduced by taking preventive measures among people with a known history of familial breast cancer. There is increasing evidence that phytochemicals of nutrients and supplements help in the prevention and cure of BRCA-related cancers by different mechanisms such as limiting DNA damage, altering estrogen metabolism, or upregulating expression of the normal BRCA allele, and ultimately enhancing DNA repair. This manuscript reviews different approaches used to identify potential phytochemicals to mitigate the risk of familial breast cancer with BRCA mutations. The findings of this review can be extended for the prevention and cure of any BRCAmutated cancer after proper experimental and clinical validation of the data.

Molecular genetics of cocaine use disorders in humans

Drug addiction, one of the major health problems worldwide, is characterized by the loss of control in drug intake, craving, and withdrawal. At the individual level, drugs of abuse produce serious consequences on health and have a negative impact on the family environment and on interpersonal and work relationships. At a wider scale, they have significant socio-economic and public health consequences and they cause delinquency and citizen insecurity. Cocaine, a psychostimulant substance, is one of the most used illicit drugs, especially in America, Western Europe, and Australia. Cocaine use disorders (CUD) are complex multifactorial conditions driven by both genetic and environmental influences. Importantly, not all people who use cocaine develop CUD, and this is due, at least in part, to biological factors that are encoded in the genome of individuals. Acute and repeated use of cocaine induces epigenetic and gene expression changes responsible for the neuronal adaptations and the remodeling of brain circuits that lead to the transition from use to abuse or dependence. The purpose of this review is to delineate such factors, which should eventually help to understand the inter-individual variability in the susceptibility to cocaine addiction. Heritability estimates for CUD are high and genetic risk factors for cocaine addiction have been investigated by candidate gene association studies (CGAS) and genome-wide association studies (GWAS), reviewed here. Also, the high comorbidity that exists between CUD and several other psychiatric disorders is well known and includes phenotypes like schizophrenia, aggression, antisocial or risk-taking behaviors. Such comorbidities are associated with a worse lifetime trajectory, and here we report shared genetic factors that may contribute to them. Gene expression changes and epigenetic modifications induced by cocaine use and chronic abuse in humans are addressed by reviewing transcriptomic studies performed on neuronal cells and on postmortem brains. We report some genes which expression is altered by cocaine that also bear genetic risk variants for the disorder. Finally, we have a glance to the pharmacogenetics of CUD treatments, still in early stages. A better understanding of the genetic underpinnings of CUD will foster the search of effective treatments and help to move forward to personalized medicine.

MicroRNAs in chronic airway diseases: Clinical correlation and translational applications

MicroRNAs (miRNAs) are short single-stranded RNAs that have pivotal roles in disease pathophysiology through transcriptional and translational modulation of important genes. It has been implicated in the development of many diseases, such as stroke, cardiovascular conditions, cancers and inflammatory airway diseases. There is recent evidence that miRNAs play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD), and could help to distinguish between T2-low (non-eosinophilic, steroid-insensitive) versus T2-high (eosinophilic, steroid-sensitive) disease endotypes. As these are the two most prevalent chronic respiratory diseases globally, with rising disease burden, miRNA research might lead to the development of new diagnostic and therapeutic targets. Research involving miRNAs in airway disease is challenging because: (i) asthma and COPD are heterogeneous inflammatory airway diseases; there are overlapping but distinct inter- and intra-disease differences in the immunological pathophysiology, (ii) there exists more than 2000 known miRNAs and a single miRNA can regulate multiple targets, (iii) differential effects of miRNAs could be present in different cellular subtypes and tissues, and (iv) dysregulated miRNA expression might be a direct consequence of an indirect effect of airway disease onset or progression. As miRNAs are actively secreted in fluids and remain relatively stable, they have the potential for biomarker development and therapeutic targets. In this review, we summarize the preclinical data on potential miRNA biomarkers that mediate different pathophysiological mechanisms in airway disease. We discuss the framework for biomarker development using miRNA and highlight the need for careful patient characterization and endotyping in the screening and validation cohorts, profiling both airway and blood samples to determine the biological fluids of choice in different disease states or severity, and adopting an untargeted approach. Collaboration between the various stakeholders - pharmaceutical companies, laboratory professionals and clinician-scientists is crucial to reduce the difficulties and cost required to bring miRNA research into the translational stage for airway diseases.

Bilobalide assuages morphine-induced addiction in hippocampal neuron cells through upregulation of microRNA-101

Bilobalide exhibits many biological activities, but its effects on morphine stimulation have not been elucidated. The research aims to explore the function and underlying mechanisms of bilobalide in morphine-led hippocampal neuron cells. Cells were treated with or without morphine or oxaliplatin (OXA), bilobalide, or SCH772984 dilutions. miR-101 inhibitor and negative control were transfected into cells. Western blot and quantitative reverse transcription-polymerase chain reaction were, respectively, conducted to measure the relative expression of proteins or RNAs. Morphine improved the expression levels of orexin1 receptor (OX1R) and c-FOS, the p/t-ERK/PKC as well. The c-FOS protein level and p/t-ERK/PKC were significantly elevated by morphine + OXA. Bilobalide had no effect on OX1R and p/t-PKC but evidently decreased the c-FOS and p/t-ERK. The p-ERK and the c-FOS accumulation levels were remarkably reduced by SCH772984. The production of miR-101 was promoted by bilobalide but inhibited by the miR-101 inhibitor. miR-101 inhibitor abolished bilobalide's inhibitory effects on p/t-ERK. Bilobalide exhibited morphine-induced effects on hippocampal neuron cells by upregulating miR-101.

Advances in the discovery of microRNA-based anticancer therapeutics: latest tools and developments

Introduction: MicroRNAs (miRNAs) are small endogenous non-coding RNAs that repress the expression of their target genes by reducing mRNA stability and/or inhibiting translation. miRNAs are known to be aberrantly regulated in cancers. Modulators of miRNA (mimics and antagonists) have emerged as novel therapeutic tools for cancer treatment.Areas covered: This review summarizes the various strategies that have been applied to correct the dysregulated miRNA in cancer cells. The authors also discuss the recent advances in the technical development and preclinical/clinical evaluation of miRNA-based therapeutic agents.Expert opinion: Application of miRNA-based therapeutics for cancer treatment is appealing because they are able to modulate multiple dysregulated genes and/or signaling pathways in cancer cells. Major obstacles hindering their clinical development include drug delivery, off-target effects, efficacious dose determination, and safety. Tumor site-specific delivery of novel miRNA therapeutics may help to minimize off-target effects and toxicity. Combination of miRNA therapeutics with other anticancer treatment modalities could provide a synergistic effect, thus allowing the use of lower dose, minimizing off-target effects, and improving the overall safety profile in cancer patients. It is critical to identify individual miRNAs with cancer type-specific and context-specific regulation of oncogenes and tumor-suppressor genes in order to facilitate the precise use of miRNA anticancer therapeutics.

Bilobalide alleviates IL-17-induced inflammatory injury in ATDC5 cells by downregulation of microRNA-125a

Ankylosing spondylitis (AS) is a high disability and greatly destructive disease. In this study, we preliminarily studied the function and mechanism of bilobalide (BIL) on interleukin (IL)-17-induced inflammatory injury in ATDC5 cells. CCK-8 and migration assays were used to detect the functions of IL-7, BIL, and microRNA (miR)-125a on cell viability and migration. The miR-125a level was changed by transfection, and tested by real-time quantitative polymerase chain reaction. Additionally, Western blot tested the levels of inflammatory factors (IL-6 and tumor necrosis factor-α), matrix metalloproteinases (MMPs), and pathway-related proteins. Moreover, the enzyme-linked immunosorbent assay also was used to detect inflammatory factor levels. IL-7 was used to construct an inflammatory injury model in ATDC5 cells. Based on this, BIL inhibited IL-17-induced cell viability, migration, and expressions of inflammatory factors and MMPs. Furthermore, we found BIL negatively regulated miR-125a, and the miR-125a mimic could partly reverse the effects of BIL on IL-17-injury. Finally, we showed that BIL inhibited the c-Jun N-terminal kinase (JNK) and nuclear factor kappa B (NF-κB) pathways, and the miR-125a mimic had the opposite effect. BIL inhibited IL-17-induced inflammatory injury in ATDC5 cells by downregulation of miR-125a via JNK and NF-κB signaling pathways.

Integrated miRNA and mRNA expression analysis uncovers drug targets in laryngeal squamous cell carcinoma patients

OBJECTIVES

The current treatment of laryngeal squamous cell carcinoma (LSCC) is based on radical surgery and radiotherapy resulting in high morbidity. Chemoradiotherapy has been used as alternative to organ sparing; however, several advanced cases presented resistance to treatment, which contributes to a high risk of recurrence and mortality. Coding RNAs and miRNAs have potential to be used as biomarkers or targets for cancer therapy.

MATERIALS AND METHODS

In this study, 36 LSCC and 5 non-neoplastic control samples were investigated using miRNA and mRNA large-scale expression analysis and a cross-validation was performed using the TCGA database (116 LSCC and 12 surrounding normal tissues).

RESULTS

The large-scale profiling revealed the involvement of 28 miRNAs and 817 genes differentially expressed in LSCC. An integrative analysis comprising predicted and experimentally validated miRNA/mRNA interactions (negatively correlated), resulted in 28 miRNAs and 543 mRNAs. Decreased expression of miR-199b was significantly associated with shorter disease-free survival in LSCC (internal and TCGA datasets). The expression levels of selected miRNAs (miR-199b-5p, miR-29c-3p, miR-204-5p, miR-125b-5p and miR-92a-3p) and genes (COL3A1, COL10A1, ERBB4, HMGA2, HLF, TOP2A, MMP3, MMP13, MMP10 and PPP1R3) were confirmed as altered in LSCC by RT-qPCR. Additionally, a drug target prediction analysis revealed drug combinations based on miRNA and mRNA expression, pointing out novel alternatives to optimize the LSCC treatment.

CONCLUSION

Collectively, these findings provide new insights in the LSCC transcriptional deregulation and potential drug targets.

Impact of Polypharmacy on Candidate Biomarker miRNomes for the Diagnosis of Fibromyalgia and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Striking Back on Treatments

Fibromyalgia (FM) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are diseases of unknown etiology presenting complex and often overlapping symptomatology. Despite promising advances on the study of miRNomes of these diseases, no validated molecular diagnostic biomarker yet exists. Since FM and ME/CFS patient treatments commonly include polypharmacy, it is of concern that biomarker miRNAs are masked by drug interactions. Aiming at discriminating between drug-effects and true disease-associated differential miRNA expression, we evaluated the potential impact of commonly prescribed drugs on disease miRNomes, as reported by the literature. By using the web search tools SM2miR, Pharmaco-miR, and repoDB, we found a list of commonly prescribed drugs that impact FM and ME/CFS miRNomes and therefore could be interfering in the process of biomarker discovery. On another end, disease-associated miRNomes may incline a patient’s response to treatment and toxicity. Here, we explored treatments for diseases in general that could be affected by FM and ME/CFS miRNomes, finding a long list of them, including treatments for lymphoma, a type of cancer affecting ME/CFS patients at a higher rate than healthy population. We conclude that FM and ME/CFS miRNomes could help refine pharmacogenomic/pharmacoepigenomic analysis to elevate future personalized medicine and precision medicine programs in the clinic.

The role of miRNAs 34a, 146a, 320a and 542 in the synergistic anticancer effects of methyl 2-(5-fluoro-2-hydroxyphenyl)-1H- benzo[d]imidazole-5-carboxylate (MBIC) with doxorubicin in breast cancer cells

Combination Index (CI) analysis suggested that MBIC and doxorubicin synergistically inhibited up to 97% of cell proliferation in ER⁺/PR⁺MCF-7 and triple negative MDA-MB-231 breast cancer cell lines. Moreover, treatment of the breast cancer cells with the combined drugs resulted in lower IC₅₀ values in contrast to the individual drug treatment. Small noncoding microRNAs (miRNA) may function as non-mutational gene regulators at post-transcriptional level of protein synthesis. In the present study, the effect of the combined treatment of MBIC and doxorubicin on the expression level of several miRNAs including miR-34a, miR-146a, miR-320a and miR-542 were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines. These miRNAs have the potential to alter the protein level of survivin, the anti-apoptotic protein and reduce the metastatic activity in human breast cancer cell lines by interfering with the nuclear accumulation of NF-κB. Our results demonstrated the several fold changes in expression of miRNAs, which is drug and cell line dependent. This finding demonstrated a functional synergistic network between miR-34a, miR-320a and miR-542 that are negatively involved in post-transcriptional regulation of survivin in MCF-7 cells. While in MDA-MB-231 cells, changes in expression level of miR-146a was correlated with inhibition of the nuclear translocation of NF-κB. The overall result suggested that alteration in protein level and location of survivin and NF-κB by miR-34a, miR-320a, miR-146a and miR-542, remarkably influenced the synergistic enhancement of combined MBIC and doxorubicin in treatment of aggressive and less aggressive human breast cancer cell lines.

Decoding the transcriptional programs activated by psychotropic drugs in the brain

Analysis of drug-induced gene expression in the brain has long held the promise of revealing the molecular mechanisms of drug actions as well as predicting their long-term clinical efficacy. However, despite some successes, this promise has yet to be fulfilled. Here, we present an overview of the current state of understanding of drug-induced gene expression in the brain and consider the obstacles to achieving a robust prediction of the properties of psychoactive compounds based on gene expression profiles. We begin with a comprehensive overview of the mechanisms controlling drug-inducible transcription and the complexity resulting from expression of noncoding RNAs and alternative gene isoforms. Particular interest is placed on studies that examine the associations within drug classes with regard to the effects on gene transcription, alterations in cell signaling and neuropharmacological drug properties. While the ability of gene expression signatures to distinguish specific clinical classes of psychotropic and addictive drugs remains unclear, some reports show that under specific constraints, drug properties can be predicted based on gene expression. Such signatures offer a simple and effective way to classify psychotropic drugs and screen novel psychoactive compounds. Finally, we note that the amount of data regarding molecular programs activated in the brain by drug treatment has grown exponentially in recent years and that future advances may therefore come in large part from integrating the currently available high-throughput data sets.

MiR-9, miR-153 and miR-124 are down-regulated by acute exposure to cocaine in a dopaminergic cell model and may contribute to cocaine dependence

Cocaine is one of the most used psychostimulant drugs worldwide. MicroRNAs are post-transcriptional regulators of gene expression that are highly expressed in brain, and several studies have shown that cocaine can alter their expression. In a previous study, we identified several protein-coding genes that are differentially expressed in a dopaminergic neuron-like model after an acute exposure to cocaine. Now, we used the prediction tool WebGestalt to identify miRNA molecules potentially involved in the regulation of these genes. Using the same cellular model, we found that seven of these miRNAs are down-regulated by cocaine: miR-124-3p, miR-124-5p, miR-137, miR-101-3p, miR-9-5p, miR-369-3p and miR-153-3p, the last three not previously related to cocaine. Furthermore, we found that three of the miRNA genes that are differentially expressed in our model (hsa-miR-9-1, hsa-miR-153-1 and hsa-miR-124-3) are nominally associated with cocaine dependence in a case-control study (2,085 cases and 4,293 controls). In summary, we highlighted novel miRNAs that may be involved in those cocaine-induced changes of gene expression that underlie addiction. Moreover, we identified genetic variants that contribute to cocaine dependence in three of these miRNA genes, supporting the idea that genes differentially expressed under cocaine may play an important role in the susceptibility to cocaine dependence.

MicroRNA-1291 targets the FOXA2-AGR2 pathway to suppress pancreatic cancer cell proliferation and tumorigenesis

Pancreatic cancer is the fourth leading cause of cancer death in the United States. Better understanding of pancreatic cancer biology may help identify new oncotargets towards more effective therapies. This study investigated the mechanistic actions of microRNA-1291 (miR-1291) in the suppression of pancreatic tumorigenesis. Our data showed that miR-1291 was downregulated in a set of clinical pancreatic carcinoma specimens and human pancreatic cancer cell lines. Restoration of miR-1291 expression inhibited pancreatic cancer cell proliferation, which was associated with cell cycle arrest and enhanced apoptosis. Furthermore, miR-1291 sharply suppressed the tumorigenicity of PANC-1 cells in mouse models. A proteomic profiling study revealed 32 proteins altered over 2-fold in miR-1291-expressing PANC-1 cells that could be assembled into multiple critical pathways for cancer. Among them anterior gradient 2 (AGR2) was reduced to the greatest degree. Through computational and experimental studies we further identified that forkhead box protein A2 (FOXA2), a transcription factor governing AGR2 expression, was a direct target of miR-1291. These results connect miR-1291 to the FOXA2-AGR2 regulatory pathway in the suppression of pancreatic cancer cell proliferation and tumorigenesis, providing new insight into the development of miRNA-based therapy to combat pancreatic cancer.

Pharmacoepigenomics of opiates and methadone maintenance treatment: current data and perspectives

Current treatments of opioid addiction include primarily maintenance medications such as methadone. Chronic exposure to opiate and/or long-lasting maintenance treatment induce modulations of gene expression in brain and peripheral tissues. There is increasing evidence that epigenetic modifications underlie these modulations. This review summarizes published results on opioid-induced epigenetic changes in animal models and in patients. The epigenetic modifications observed with other drugs of abuse often used by opiate abusers are also outlined. Specific methadone maintenance treatment induced epigenetic modifications at different treatment stages may be combined with the ones resulting from patients’ substance use history. Therefore, research comparing groups of addicts with similar history and substances use disorders but contrasting for well-characterized treatment phenotypes should be encouraged.

Promising therapeutic role of miR-27b in tumor

MicroRNAs are small nonprotein-encoding RNAs ranging from 18 to 25 nucleotides in size and regulate multiple biological pathways via directly targeting a variety of associated genes in cancers. MicroRNA-27b is a highly conserved MicroRNA throughout vertebrates and there are two homologs (hsa-miR-27a and hsa-miR-27b) in humans. MicroRNA-27b is an intragenic microRNA located on chromosome 9q22.1 within the C9orf3 gene, clustering with miR-23b and miR-24-1 in human. As a frequently dysregulated microRNA in human cancers, microRNA-27b could function as a tumor suppressor or an oncogenic microRNA. More and more studies indicate that microRNA-27b is involved in affecting various biological processes, such as angiogenesis, proliferation, metastasis, and drug resistance, and thus may act as a promising therapeutic target in human cancers. In this review, we discuss the role of microRNA-27b in detail and offer novel insights into molecular targeting therapy for cancers.

The Promises of Quantitative Proteomics in Precision Medicine

Precision medicine approach has a potential to ensure optimum efficacy and safety of drugs at individual patient level. Physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models could play a significant role in precision medicine by predicting interindividual variability in drug disposition and response. In order to develop robust PBPK/PD models, it is imperative that the critical physiological parameters affecting drug disposition and response and their variability are precisely characterized. Currently used PBPK/PD modeling software, for example, Simcyp and Gastroplus, encompass information such as organ volumes, blood flows to organs, body fat composition, glomerular filtration rate, etc. However, the information on the interindividual variability of the majority of the proteins associated with PK and PD, for example, drug metabolizing enzymes, transporters, and receptors, are not fully incorporated into these PBPK modeling platforms. Such information is significant because the population factors such as age, genotype, disease, and gender can affect abundance or activity of these proteins. To fill this critical knowledge gap, mass spectrometry-based quantitative proteomics has emerged as an important technique to characterize interindividual variability in the protein abundance of drug metabolizing enzymes, transporters, and receptors. Integration of these quantitative proteomics data into in silico PBPK/PD modeling tools will be crucial toward precision medicine.

MiRNAs and miRNA Polymorphisms Modify Drug Response

Differences in expression of drug response-related genes contribute to inter-individual variation in drugs’ biological effects. MicroRNAs (miRNAs) are small noncoding RNAs emerging as new players in epigenetic regulation of gene expression at post-transcriptional level. MiRNAs regulate the expression of genes involved in drug metabolism, drug transportation, drug targets and downstream signal molecules directly or indirectly. MiRNA polymorphisms, the genetic variations affecting miRNA expression and/or miRNA-mRNA interaction, provide a new insight into the understanding of inter-individual difference in drug response. Here, we provide an overview of the recent progress in miRNAs mediated regulation of biotransformation enzymes, drug transporters, and nuclear receptors. We also describe the implications of miRNA polymorphisms in cancer chemotherapy response.

Non-coding RNA/microRNA-modulatory dietary factors and natural products for improved cancer therapy and prevention: Alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins

Non-coding small RNA molecules, the microRNAs (miRNAs), contribute decisively to the epigenetic regulation processes in cancer cells. Problematic pathogenic properties of cancer cells and the response of cancers towards anticancer drugs are highly influenced by miRNAs. Both increased drug activity and formation of tumor resistance are regulated by miRNAs. Further to this, the survival and proliferation of cancer cells and the formation of metastases is based on the modulated expression of certain miRNAs. In particular, drug-resistant cancer stem-like cells (CSCs) depend on the presence and absence of specific miRNAs. Fortunately, several small molecule natural compounds were discovered that target miRNAs involved in the modulation of tumor aggressiveness and drug resistance. This review gives an overview of the effects of a selection of naturally occurring small molecules (alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins) on miRNAs that are closely tangled with cancer diseases.

Atorvastatin attenuation of ABCB1 expression is mediated by microRNA miR-491-3p in Caco-2 cells

AIM

Atorvastatin, a HMG-CoA reductase inhibitor, used in the treatment of hypercholesterolemia, has been previously shown to regulate ABCB1 expression in vivo and in vitro. We hypothesized that the statin could regulate gene expression of ABCB1 transporter via microRNAs.

METHODS

Expression of microRNAs and ABCB1 mRNA was examined in atorvastatin-treated and control cells using real-time PCR. miR-491-3P mimic and inhibitor were transfected in Caco-2 and ABCB1 expression was monitored by western blot and real-time PCR.

RESULTS

In HepG2 cells, none of the microRNAs predicted to target ABCB1 3'UTR was regulated by atorvastatin treatment. In agreement with this, ABCB1 3'UTR activity was not modulated in HepG-2 cells after 48h-treatment as measured by luciferase assay. In Caco-2 cells, atorvastatin treatment provoked a decrease in luciferase activity and, accordingly, miR-491-3p was upregulated about 2.7 times after 48h-statin treatment. Luciferase analysis of miR-491-3p with a mimetic or inhibitor of miR-491-3p revealed that this microRNA could target ABCB1 3'UTR, as after miR-491-3p inhibition, ABCB1 levels were increased by two-fold, and miR-491-3p superexpression decreased ABCB1 3'UTR activity. Finally, functional analysis revealed that treatment with miR-491-3p inhibitor could reverses atorvastatin attenuation of ABCB1 (Pg-p) protein levels.

CONCLUSION

Our results suggest atorvastatin control ABCB1 expression via miR-491-3p in Caco-2 cells. This finding may be an important mechanism of statin drug-drug interaction, since common concomitant drugs used in the prevention of cardiovascular diseases are ABCB1 substrates.

Plasma miR-142 accounting for the missing heritability of CYP3A4/5 functionality is associated with pharmacokinetics of clopidogrel

AIM

To investigate whether plasma miRNAs targeting CYP3A4/5 have an impact on the variance of pharmacokinetics of clopidogrel.

MATERIALS & METHODS

The contribution of 13 miRNAs to the CYP3A4/5 gene expression and activity was investigated in 55 liver tissues. The association between plasma miRNAs targeting CYP3A4/5 mRNA and clopidogrel pharmacokinetics was analyzed in 31 patients with coronary heart disease who received 300 mg loading dose of clopidogrel.

RESULTS

Among 13 miRNAs, miR-142 was accounting for 12.2% (p = 0.002) CYP3A4 mRNA variance and 9.4% (p = 0.005) CYP3A5 mRNA variance, respectively. Plasma miR-142 was negatively associated with H4 Cmax (r = -0.5269; p = 0.0040) and associated with H4 AUC0-4h (r = -0.4986; p = 0.0069) after 300 mg loading dose of clopidogrel in coronary heart disease patients.

CONCLUSION

miR-142 could account for a part of missing heritability of CYP3A4/5 functionality related to clopidogrel activation.

Transcriptome association analysis identifies miR-375 as a major determinant of variable acetaminophen glucuronidation by human liver

Acetaminophen is the leading cause of acute liver failure (ALF) in many countries including the United States. Hepatic glucuronidation by UDP-glucuronosyltransferase (UGT) 1A subfamily enzymes is the major route of acetaminophen elimination. Reduced glucuronidation may predispose some individuals to acetaminophen-induced ALF, but mechanisms underlying reduced glucuronidation are poorly understood. We hypothesized that specific microRNAs (miRNAs) may reduce UGT1A activity by direct effects on the UGT1A 3'-UTR shared by all UGT1A enzyme transcripts, or by indirect effects on transcription factors regulating UGT1A expression. We performed an unbiased miRNA whole transcriptome association analysis using a bank of human livers with known acetaminophen glucuronidation activities. Of 754 miRNAs evaluated, 9 miRNAs were identified that were significantly overexpressed (p<0.05; >2-fold) in livers with low acetaminophen glucuronidation activities compared with those with high activities. miR-375 showed the highest difference (>10-fold), and was chosen for further mechanistic validation. We demonstrated using in silico analysis and luciferase reporter assays that miR-375 has a unique functional binding site in the 3'-UTR of the aryl hydrocarbon receptor (AhR) gene. Furthermore overexpression of miR-375 in LS180 cells demonstrated significant repression of endogenous AhR protein (by 40%) and mRNA (by 10%), as well as enzyme activity and/or mRNA of AhR regulated enzymes including UGT1A1, UGT1A6, and CYP1A2, without affecting UGT2B7, which is not regulated by AhR. Thus miR-375 is identified as a novel repressor of UGT1A-mediated hepatic acetaminophen glucuronidation through reduced AhR expression, which could predispose some individuals to increased risk for acetaminophen-induced ALF.

Emerging Roles for MicroRNAs in Perioperative Medicine

MicroRNAs (miRNAs) are small, non-protein-coding, single-stranded RNAs. They function as posttranscriptional regulators of gene expression by interacting with target mRNAs. This process prevents translation of target mRNAs into a functional protein. miRNAs are considered to be functionally involved in virtually all physiologic processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis, and inflammation. Many of these functions have important implications for anesthesiology and critical care medicine. Studies indicate that miRNA expression levels can be used to predict the risk for eminent organ injury or sepsis. Pharmacologic approaches targeting miRNAs for the treatment of human diseases are currently being tested in clinical trials. The present review highlights the important biological functions of miRNAs and their usefulness as perioperative biomarkers and discusses the pharmacologic approaches that modulate miRNA functions for disease treatment. In addition, the authors discuss the pharmacologic interactions of miRNAs with currently used anesthetics and their potential to impact anesthetic toxicity and side effects.

Transcriptomic and genetic studies identify NFAT5 as a candidate gene for cocaine dependence

Cocaine reward and reinforcing effects are mediated mainly by dopaminergic neurotransmission. In this study, we aimed at evaluating gene expression changes induced by acute cocaine exposure on SH-SY5Y-differentiated cells, which have been widely used as a dopaminergic neuronal model. Expression changes and a concomitant increase in neuronal activity were observed after a 5 μM cocaine exposure, whereas no changes in gene expression or in neuronal activity took place at 1 μM cocaine. Changes in gene expression were identified in a total of 756 genes, mainly related to regulation of transcription and gene expression, cell cycle, adhesion and cell projection, as well as mitogen-activeated protein kinase (MAPK), CREB, neurotrophin and neuregulin signaling pathways. Some genes displaying altered expression were subsequently targeted with predicted functional single-nucleotide polymorphisms (SNPs) in a case-control association study in a sample of 806 cocaine-dependent patients and 817 controls. This study highlighted associations between cocaine dependence and five SNPs predicted to alter microRNA binding at the 3'-untranslated region of the NFAT5 gene. The association of SNP rs1437134 with cocaine dependence survived the Bonferroni correction for multiple testing. A functional effect was confirmed for this variant by a luciferase reporter assay, with lower expression observed for the rs1437134G allele, which was more pronounced in the presence of hsa-miR-509. However, brain volumes in regions of relevance to addiction, as assessed with magnetic resonance imaging, did not correlate with NFAT5 variation. These results suggest that the NFAT5 gene, which is upregulated a few hours after cocaine exposure, may be involved in the genetic predisposition to cocaine dependence.

Nucleosome Repositioning: A Novel Mechanism for Nicotine- and Cocaine-Induced Epigenetic Changes

Drugs of abuse modify behavior by altering gene expression in the brain. Gene expression can be regulated by changes in DNA methylation as well as by histone modifications, which alter chromatin structure, DNA compaction and DNA accessibility. In order to better understand the molecular mechanisms directing drug-induced changes in chromatin structure, we examined DNA-nucleosome interactions within promoter regions of 858 genes in human neuroblastoma cells (SH-SY5Y) exposed to nicotine or cocaine. Widespread, drug- and time-resolved repositioning of nucleosomes was identified at the transcription start site and promoter region of multiple genes. Nicotine and cocaine produced unique and shared changes in terms of the numbers and types of genes affected, as well as repositioning of nucleosomes at sites which could increase or decrease the probability of gene expression based on DNA accessibility. Half of the drug-induced nucleosome positions approximated a theoretical model of nucleosome occupancy based on physical and chemical characteristics of the DNA sequence, whereas the basal or drug naïve positions were generally DNA sequence independent. Thus we suggest that nucleosome repositioning represents an initial dynamic genome-wide alteration of the transcriptional landscape preceding more selective downstream transcriptional reprogramming, which ultimately characterizes the cell- and tissue-specific responses to drugs of abuse.

The effects of microRNA on the absorption, distribution, metabolism and excretion of drugs

The importance of genetic factors (e.g. sequence variation) in the absorption, distribution, metabolism, excretion (ADME) and overall efficacy of therapeutic agents is well established. Our ability to identify, interpret and utilize these factors is the subject of much clinical investigation and therapeutic development. However, drug ADME and efficacy are also heavily influenced by epigenetic factors such as DNA/histone methylation and non-coding RNAs [especially microRNAs (miRNAs)]. Results from studies using tools, such as in silico miRNA target prediction, in vitro functional assays, nucleic acid profiling/sequencing and high-throughput proteomics, are rapidly expanding our knowledge of these factors and their effects on drug metabolism. Although these studies reveal a complex regulation of drug ADME, an increased understanding of the molecular interplay between the genome, epigenome and transcriptome has the potential to provide practically useful strategies to facilitate drug development, optimize therapeutic efficacy, circumvent adverse effects, yield novel diagnostics and ultimately become an integral component of personalized medicine.

A miRNA-driven inference model to construct potential drug-disease associations for drug repositioning

Increasing evidence discovered that the inappropriate expression of microRNAs (miRNAs) will lead to many kinds of complex diseases and drugs can regulate the expression level of miRNAs. Therefore human diseases may be treated by targeting some specific miRNAs with drugs, which provides a new perspective for drug repositioning. However, few studies have attempted to computationally predict associations between drugs and diseases via miRNAs for drug repositioning. In this paper, we developed an inference model to achieve this aim by combining experimentally supported drug-miRNA associations and miRNA-disease associations with the assumption that drugs will form associations with diseases when they share some significant miRNA partners. Experimental results showed excellent performance of our model. Case studies demonstrated that some of the strongly predicted drug-disease associations can be confirmed by the publicly accessible database CTD (www.ctdbase.org), which indicated the usefulness of our inference model. Moreover, candidate miRNAs as molecular hypotheses underpinning the associations were listed to guide future experiments. The predicted results were released for further studies. We expect that this study will provide help in our understanding of drug-disease association prediction and in the roles of miRNAs in drug repositioning.

MicroRNAs as key regulators of xenobiotic biotransformation and drug response

In the last decade, microRNAs have emerged as key factors that negatively regulate mRNA expression. It has been estimated that more than 50% of protein-coding genes are under microRNA control and each microRNA is predicted to repress several mRNA targets. In this respect, it is recognized that microRNAs play a vital role in various cellular and molecular processes and that, depending on the biological pathways in which they intervene, distorted expression of microRNAs can have serious consequences. It has recently been shown that specific microRNA species are also correlated with toxic responses induced by xenobiotics. Since the latter are primarily linked to the extent of detoxification in the liver by phase I and phase II biotransformation enzymes and influx and efflux drug transporters, the regulation of the mRNA levels of this particular set of genes through microRNAs is of great importance for the overall toxicological outcome. Consequently, in this paper, an overview of the current knowledge with respect to the complex interplay between microRNAs and the expression of biotransformation enzymes and drug transporters in the liver is provided. Nuclear receptors and transcription factors, known to be involved in the transcriptional regulation of these genes, are also discussed.

Integrated microRNA-mRNA analysis of coronary artery disease

Although patients with coronary artery disease (CAD) have a high mortality rate, the pathogenesis of CAD is still poorly understood. The purpose of this study was to explore the underlying molecular mechanisms and potential target molecules for CAD. The platelet miRNA (GSE28858) and blood mRNA (GSE42148) expression profiles of patients with CAD and healthy controls were downloaded from Gene Expression Omnibus. Differentially expressed miRNAs and genes (DEGs) were identified by significant analysis of microarray algorithm after data preprocessing. Furthermore, the miRNA-target gene regulatory network was constructed based on miRecords database. The spearman correlation coefficients (ρ) between miRNAs and their target genes were calculated. Six up- (miR-340, miR-545, miR-451, miR454-5p, miR-624 and miR-585) and four down-regulated (miR-199a, miR-17-3p, miR-154 and miR-339) miRNAs were screened. Total 295 target genes of miR-545, miR-451, miR-585 and miR-154 were predicted. Among these 295 target genes, 7 genes were DEGs. Further analysis showed miR-545-TFEC and miR-585-SPOCK1 were highly positively correlated (ρ = 0.808091264; ρ = 0.874680776) in CAD samples. Therefore, differentially expressed miRNAs might participate in the pathogenesis of CAD by regulating their target genes.

Genetic variation in the 3'-UTR of CYP1A2, CYP2B6, CYP2D6, CYP3A4, NR1I2, and UGT2B7: potential effects on regulation by microRNA and pharmacogenomics relevance

Introduction: Pharmacogenomics research has concentrated on variation in genes coding for drug metabolizing enzymes, transporters and nuclear receptors. However, variation affecting microRNA could also play a role in drug response. This project set out to investigate potential microRNA target sites in 11 genes and the extent of variation in the 3′-UTR of six selected genes; CYP1A2, CYP2B6, CYP2D6, CYP3A4, NR1I2, and UGT2B7.

Methods: Fifteen microRNA target prediction algorithms were used to identify microRNAs predicted to regulate 11 genes. The 3′-UTR of the 6 genes which topped the list of potential microRNA targets was sequenced in 30 black South Africans. In addition, genetic variants within these genes were investigated for interference with mRNA-microRNA interactions. Potential effects of observed variants were determined using in silico prediction tools.

Results: The 11 genes coding for DMEs, transporters and nuclear receptors were predicted to be targets of microRNAs with CYP2B6, NR1I2 (PXR), CYP3A4, and CYP1A2, interacting with the most microRNAs. The majority of identified genetic variants were predicted to interfere with microRNA regulation. For example, the variant, rs1054190C in NR1I2 was predicted to result in the presence of a binding site for the microRNA miR-1250-5p, while the variant rs1054191G was predicted to result in the absence of a recognition site for miR-371b-3p, miR-4258 and miR-4707-3p. Fifteen of the seventeen, novel variants occurred within microRNA target sequences.

Conclusion: The 3′-UTR harbors variation that is likely to influence regulation of specific genes by microRNA. In silico prediction followed by functional validation could aid in decoding the contribution of variation in the 3′-UTR, to some unexplained heritability that affects drug response. Understanding the specific role of each microRNA may lead to identification of markers for targeted therapy and therefore improve personalized drug treatment.

miRNAs for the detection of multidrug resistance: overview and perspectives

The goal of the present paper is to establish and validate the link between cancer diagnosis and therapy by microRNAs detection. The induction in vitro of some specific microRNAs after treatment with MDR ligands has been outlined. Starting from the results obtained by in vitro induction of MDCK and MDCK-MDR1 cells treated by a MDR1 ligand, a new scenario in the early diagnosis and chemotherapy could be disclosed. To corroborate this perspective a short overview on pancreatic cancer diagnosis and chemotherapeutic treatment has been reported.

Epigenetics and depression: return of the repressed

INTRODUCTION

Epigenetics has recently emerged as a potential mechanism by which adverse environmental stimuli can result in persistent changes in gene expression. Epigenetic mechanisms function alongside the DNA sequence to modulate gene expression and ultimately influence protein production. The current review provides an introduction and overview of epigenetics with a particular focus on preclinical and clinical studies relevant to major depressive disorder (MDD).

METHODS

PubMed and Web of Science databases were interrogated from January 1995 up to December 2012 using combinations of search terms, including "epigenetic", "microRNA" and "DNA methylation" cross referenced with "depression", "early life stress" and "antidepressant".

RESULTS

There is an association between adverse environmental stimuli, such as early life stress, and epigenetic modification of gene expression. Epigenetic changes have been reported in humans with MDD and may serve as biomarkers to improve diagnosis. Antidepressant treatments appear to reverse or initiate compensatory epigenetic alterations that may be relevant to their mechanism of action.

LIMITATIONS

As a narrative review, the current report was interpretive and qualitative in nature.

CONCLUSION

Epigenetic modification of gene expression provides a mechanism for understanding the link between long-term effects of adverse life events and the changes in gene expression that are associated with depression. Although still a developing field, in the future, epigenetic modifications of gene expression may provide novel biomarkers to predict future susceptibility and/or onset of MDD, improve diagnosis, and aid in the development of epigenetics-based therapies for depression.

MicroRNA: a prognostic biomarker and a possible druggable target for circumventing multidrug resistance in cancer chemotherapy

Multidrug resistance (MDR) is a major obstacle to successful cancer treatment. It is often associated with an increased efflux of a variety of structurally unrelated anticancer drugs by ATP-binding cassette (ABC) transporters including P-gp, ABCG2 and MRP1. MicroRNAs (miRNAs) are small non-coding RNAs that govern posttranscriptional regulation of target genes by interacting with specific sequences in their 3′ untranslated region (3′UTR), thereby promoting mRNA degradation or suppressing translation. Accumulating evidence suggests that alterations in miRNAs contribute to resistance to anticancer drugs. While miRNAs are well-known to be dysregulated in cancer, recent literature revealed that miRNA levels in biological samples may be correlated with chemotherapy response. This review summarized the coordinated network by which miRNA regulated MDR transporters. The usefulness of miRNAs as prognostic biomarkers for predicting chemotherapeutic outcome is discussed. MiRNAs may also represent druggable targets for circumvention of MDR.

Small nucleolar RNA-derived microRNA hsa-miR-1291 modulates cellular drug disposition through direct targeting of ABC transporter ABCC1

Multidrug resistance-associated protein 1 (MRP1/ABCC1) is an important membrane transporter that contributes to cellular disposition of many endobiotic and xenobiotic agents, and it can also confer multidrug resistance. This study aimed to investigate the role of human noncoding microRNA-1291 (hsa-miR-1291) in regulation of ABCC1 and drug disposition. Bioinformatics analyses indicated that hsa-miR-1291, localized within the small nucleolar RNA H/ACA box 34 (SNORA34), might target ABCC1 3'-untranslated region (3'UTR). Using splinted ligation small RNA detection method, we found that SNORA34 was processed into hsa-miR-1291 in human pancreatic carcinoma PANC-1 cells. Luciferase reporter assays showed that ABCC1 3'-UTR-luciferase activity was decreased by 20% in cells transfected with hsa-miR-1291 expression plasmid, and increased by 40% in cells transfected with hsa-miR-1291 antagomir. Furthermore, immunoblot study revealed that ABCC1 protein expression was sharply reduced in hsa-miR-1291-stably transfected PANC-1 cells, which was attenuated by hsa-miR-1291 antagomir. The change of ABCC1 protein expression was associated with an alternation in mRNA expression. In addition, hsa-miR-1291-directed downregulation of ABCC1 led to a greater intracellular drug accumulation and sensitized the cells to doxorubicin. Together, our results indicate that hsa-miR-1291 is derived from SNORA34 and modulates cellular drug disposition and chemosensitivity through regulation of ABCC1 expression. These findings shall improve the understanding of microRNA-controlled epigenetic regulatory mechanisms underlying multidrug resistance and interindividual variability in pharmacokinetics.

MicroRNA-21-3p, a berberine-induced miRNA, directly down-regulates human methionine adenosyltransferases 2A and 2B and inhibits hepatoma cell growth

Methionine adenosyltransferase (MAT) is the cellular enzyme that catalyzes the synthesis of S-adenosylmethionine (SAM), the principal biological methyl donor and a key regulator of hepatocyte proliferation, death and differentiation. Two genes, MAT1A and MAT2A, encode 2 distinct catalytic MAT isoforms. A third gene, MAT2B, encodes a MAT2A regulatory subunit. In hepatocellular carcinoma (HCC), MAT1A downregulation and MAT2A upregulation occur, known as the MAT1A:MAT2A switch. The switch is accompanied with an increasing expression of MAT2B, which results in decreased SAM levels and facilitates cancer cell growth. Berberine, an isoquinoline alkaloid isolated from many medicinal herbs such as Coptis chinensis, has a wide range of pharmacological effects including anti-cancer effects. Because drug-induced microRNAs have recently emerged as key regulators in guiding their pharmacological effects, we examined whether microRNA expression is differentially altered by berberine treatment in HCC. In this study, we used microRNA microarrays to find that the expression level of miR-21-3p (previously named miR-21*) increased after berberine treatment in the HepG2 human hepatoma cell line. To predict the putative targets of miR-21-3p, we integrated the gene expression profiles of HepG2 cells after berberine treatment by comparing with a gene list generated from sequence-based microRNA target prediction software. We then confirmed these predictions through transfection of microRNA mimics and a 3' UTR reporter assay. Our findings provide the first evidence that miR-21-3p directly reduces the expression of MAT2A and MAT2B by targeting their 3' UTRs. In addition, an overexpression of miR-21-3p increased intracellular SAM contents, which have been proven to be a growth disadvantage for hepatoma cells. The overexpression of miR-21-3p suppresses growth and induces apoptosis in HepG2 cells. Overall, our results demonstrate that miR-21-3p functions as a tumor suppressor by directly targeting both MAT2A and MAT2B, indicating its therapeutic potential in HCC.

MicroRNAs and Glucocorticoid-Induced Apoptosis in Lymphoid Malignancies

The initial response of lymphoid malignancies to glucocorticoids (GCs) is a critical parameter predicting successful treatment. Although being known as a strong inducer of apoptosis in lymphoid cells for almost a century, the signaling pathways regulating the susceptibility of the cells to GCs are only partly revealed. There is still a need to develop clinical tests that can predict the outcome of GC therapy. In this paper, I discuss important parameters modulating the pro-apoptotic effects of GCs, with a specific emphasis on the microRNA world comprised of small players with big impacts. The journey through the multifaceted complexity of GC-induced apoptosis brings forth explanations for the differential treatment response and raises potential strategies for overcoming drug resistance.

MicroRNAs in opioid pharmacology

MicroRNAs (miRNA), a class of ~22-nucleotide RNA molecules, are important gene regulators that bind to the target sites of mRNAs to inhibit the gene expressions either through translational inhibition or mRNA destabilization. There are growing evidences that miRNAs have played several regulatory roles in opioid pharmacology. Like other research fields such as cancer biology, the area where numerous miRNAs are found to be involved in gene regulation, we assume that in opioid studies including research fields of drug additions and opioid receptor regulation, there may be more miRNAs waiting to be discovered. This review will summarize our current knowledge of miRNA functions on opioids biology and briefly describe future research directions of miRNAs related to opioids.

XenomiRs and miRNA homeostasis in health and disease: evidence that diet and dietary miRNAs directly and indirectly influence circulating miRNA profiles

Contributions of dietary miRNAs to circulating small RNA profiles would have profound implications for interpretation of miRNA biomarker studies: presumptive disease-specific markers might instead indicate responses to disease-associated quantitative or qualitative dietary alteration. This examination weighs the evidence for a 2-fold hypothesis: first, that ingested biological matter contributes directly to the miRNA complement of body compartments; and second, that these diet-derived exogenous miRNAs (or "xenomiRs") affect total miRNA profiles as part of a circulating miRNA homeostasis that is altered in many diseases. Homeostasis of high-density lipoprotein (HDL), a known miRNA carrier-provides a model as a proposed component of broader miRNA homeostasis. Further research into the dietary xenomiR hypothesis is needed to ensure rigor in the search for truly disease-specific miRNA biomarkers.

Noncoding microRNAs: small RNAs play a big role in regulation of ADME?

There are considerable interindividual variations in drug absorption, distribution, metabolism and excretion (ADME) in humans, which may lead to undesired drug effects in pharmacotherapy. Some of the mechanistic causes are known, e.g., genetic polymorphism, inhibition and induction of ADME enzymes and transporters, while others such as posttranscriptional regulation of ADME genes are under active study. MicroRNAs (miRNAs) are a large group of small, noncoding RNAs that control posttranscriptional expression of target genes. More than 1000 miRNAs have been identified in the human genome, which may regulate thousands of protein-coding genes. Some miRNAs directly or indirectly control the expression of xenobiotic-metabolizing cytochrome P450 enzymes, ATP-binding cassette or solute carrier transporters and/or nuclear receptors. Consequently, intervention of miRNA epigenetic signaling may alter ADME gene expression, change the capacity of drug metabolism and transport, and influence the sensitivity of cells to xenobiotics. In addition, the expression of some ADME regulatory miRNAs is significantly changed in cells following the exposure to a given drug, and the consequent changes in ADME gene expression might result in distinct ADME properties and drug response. In this review, we summarized recent findings on the role of noncoding miRNAs in epigenetic regulation of ADME genes and discussed the potential impact on pharmacokinetics and pharmacodynamics.

MicroRNAs in Neurotoxicity

MicroRNAs are gaining importance as regulators of gene expression with the capability to fine-tune and modulate cellular events. The complex network with their selective targets (mRNAs/genes) pave way for regulation of many physiological processes. Dysregulation of normal neuronal activities could result in accumulation of substances that are detrimental to neuronal functions and subsequently result in neurotoxicity. Neurotoxicity-mediated pathophysiological conditions could then manifest as diseases or disabilities like Parkinson's and Alzheimer's which have debilitating implications. Such toxicity can be a result of individuals predisposed due to genetic inheritance or from other sources such as brain tumours. Neurotoxicity can also be brought about by external agents like drugs and alcohol as well as brain injury with miRNAs playing a pivotal role in diseases. It is therefore vital to understand the expression of these microRNAs and their impact on neuronal activities. In this paper, we discuss some of the neuronal pathophysiological conditions that could be caused by dysregulated microRNAs.

Advances in understanding the relationship between microRNAs and colorectal cancer

The development of colorectal cancer is a multi-factorial, multi-step process in which abnormal gene expression may play an important role. In recent years, it has been reported that microRNAs (miRNAs), which widely exist in eukaryotes, are closely related to gene expression regulation in colorectal cancer. These findings have greatly expanded our understanding of the pathogenesis of colorectal cancer and provide new ideas and methods for the diagnosis and treatment of this malignancy.

Platelets in patients with premature coronary artery disease exhibit upregulation of miRNA340* and miRNA624*

Background

Coronary artery disease (CAD) is the leading cause of human morbidity and mortality worldwide, underscoring the need to improve diagnostic strategies. Platelets play a major role, not only in the process of acute thrombosis during plaque rupture, but also in the formation of atherosclerosis itself. MicroRNAs are endogenous small non-coding RNAs that control gene expression and are expressed in a tissue and disease-specific manner. Therefore they have been proposed to be useful biomarkers. It remains unknown whether differences in miRNA expression levels in platelets can be found between patients with premature CAD and healthy controls.

Methodology/Principal Findings

In this case-control study we measured relative expression levels of platelet miRNAs using microarrays from 12 patients with premature CAD and 12 age- and sex-matched healthy controls. Six platelet microRNAs were significantly upregulated (miR340*, miR451, miR454*, miR545:9.1. miR615-5p and miR624*) and one miRNA (miR1280) was significantly downregulated in patients with CAD as compared to healthy controls. To validate these results, we measured the expression levels of these candidate miRNAs by qRT-PCR in platelets of individuals from two independent cohorts; validation cohort I consisted of 40 patients with premature CAD and 40 healthy controls and validation cohort II consisted of 27 patients with artery disease and 40 healthy relatives. MiR340* and miR624* were confirmed to be upregulated in patients with CAD as compared to healthy controls in both validation cohorts.

Conclusion/Significance

Two miRNAs in platelets are significantly upregulated in patients with CAD as compared to healthy controls. Whether the two identified miRNAs can be used as biomarkers and whether they are cause or consequence of the disease remains to be elucidated in a larger prospective study.