MicroRNA and diseases: therapeutic potential as new generation of drugs

6-Shogaol alleviates high-fat diet induced hepatic steatosis through miR-3066-5p/Grem2 pathway

The purpose of this study is to investigate the mechanism by which 6-shogaol ameliorates hepatic steatosis via miRNA-mRNA interaction analysis. C57BL/6 J mice were fed a high-fat diet (HFD) for 12 weeks, during which 6-shogaol was administered orally. The liver lipid level, liver function and oxidative damage in mice were evaluated. mRNA sequencing, miRNA sequencing, and RT-qPCR were employed to compare the expression profiles between the HFD group and the 6-shogaol-treated group. High-throughput sequencing was used to construct the mRNA and miRNA libraries. Target prediction and integration analysis identified eight potential miRNA-mRNA pairs involved in hepatic steatosis, which were subsequently validated in liver tissues and AML12 cells. The findings revealed that 6-shogaol modulates the miR-3066-5p/Grem2 pathway, thereby improving hepatic steatosis. This study provides new insights into the mechanisms through which 6-shogaol alleviates hepatic steatosis, establishing a foundation for future research on natural active compounds for the treatment of metabolic diseases.

Role of Serum Micro-RNA-122-5p Expression as a Circulatory Biomarker in People Having Both Knee Osteoarthritis and Osteoporosis: A Case-Control Study

Background Although knee osteoarthritis (KOA) and osteoporosis (OP) manifest distinct pathophysiologies, they share numerous similarities. These health conditions are commonly found in older individuals, particularly among women. The objective of this study is to explore the expression of micro-RNA (miRNA) 122-5p (miR-122-5p) in people affected by both KOA and OP. The main aim is to identify diagnostic biomarkers and potential therapeutic targets, which could help develop personalized treatment approaches. Methods As part of the study, a total of 268 serum samples were collected from the participants, who were divided into four groups: KOA, OP, KOA and OP, and controls, with 67 subjects per group. The miRNA species-containing total RNA was isolated from the serum samples using an miRNeasy serum/plasma kit by QIAGEN (Hilden, Germany). The expression of miR-122-5p was examined in each group using real-time quantitative polymerase chain reaction. Results Expression of miR-122-5p in all three groups (KOA, OP, and common group of KOA and OP) was significantly upregulated, and the fold change value was much higher in the group having both diseases. Conclusions These results might contribute to the identification of cases at risk, early diagnosis, and development, and might also contribute to the development of therapeutic targets in subjects having both KOA and OP.

Understanding the multifaceted role of miRNAs in Alzheimer's disease pathology

Small non-coding RNAs (miRNAs) regulate gene expression by binding to mRNA and mediating its degradation or inhibiting translation. Since miRNAs can regulate the expression of several genes, they have multiple roles to play in biological processes and human diseases. The majority of miRNAs are known to be expressed in the brain and are involved in synaptic functions, thus marking their presence and role in major neurodegenerative disorders, including Alzheimer's disease (AD). In AD, amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) are known to be the major hallmarks. The clearance of Aβ and tau is known to be associated with miRNA dysregulation. In addition, the β-site APP cleaving enzyme (BACE 1), which cleaves APP to form Aβ, is also found to be regulated by miRNAs, thus directly affecting Aβ accumulation. Growing evidences suggest that neuroinflammation can be an initial event in AD pathology, and miRNAs have been linked with the regulation of neuroinflammation. Inflammatory disorders have also been associated with AD pathology, and exosomes associated with miRNAs are known to regulate brain inflammation, suggesting for the role of systemic miRNAs in AD pathology. Several miRNAs have been related in AD, years before the clinical symptoms appear, most of which are associated with regulating the cell cycle, immune system, stress responses, cellular senescence, nerve growth factor (NGF) signaling, and synaptic regulation. Phytochemicals, especially polyphenols, alter the expression of various miRNAs by binding to miRNAs or binding to the transcriptional activators of miRNAs, thus control/alter various metabolic pathways. Awing to the sundry biological processes being regulated by miRNAs in the brain and regulation of expression of miRNAs via phytochemicals, miRNAs and the regulatory bioactive phytochemicals can serve as therapeutic agents in the treatment and management of AD.

Genomic and transcriptomic advances in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder and the most common motor neuron disease. ALS shows substantial clinical and molecular heterogeneity. In vitro and in vivo models coupled with multiomic techniques have provided important contributions to unraveling the pathomechanisms underlying ALS. To date, despite promising results and accumulating knowledge, an effective treatment is still lacking. Here, we provide an overview of the literature on the use of genomics, epigenomics, transcriptomics and microRNAs to deeply investigate the molecular mechanisms developing and sustaining ALS. We report the most relevant genes implicated in ALS pathogenesis, discussing the use of different high-throughput sequencing techniques and the role of epigenomic modifications. Furthermore, we present transcriptomic studies discussing the most recent advances, from microarrays to bulk and single-cell RNA sequencing. Finally, we discuss the use of microRNAs as potential biomarkers and promising tools for molecular intervention. The integration of data from multiple omic approaches may provide new insights into pathogenic pathways in ALS by shedding light on diagnostic and prognostic biomarkers, helping to stratify patients into clinically relevant subgroups, revealing novel therapeutic targets and supporting the development of new effective therapies.

Methyl Donors, Epigenetic Alterations, and Brain Health: Understanding the Connection

Methyl donors such as choline, betaine, folic acid, methionine, and vitamins B6 and B12 are critical players in the one-carbon metabolism and have neuroprotective functions. The one-carbon metabolism comprises a series of interconnected chemical pathways that are important for normal cellular functions. Among these pathways are those of the methionine and folate cycles, which contribute to the formation of S-adenosylmethionine (SAM). SAM is the universal methyl donor of methylation reactions such as histone and DNA methylation, two epigenetic mechanisms that regulate gene expression and play roles in human health and disease. Epigenetic mechanisms have been considered a bridge between the effects of environmental factors, such as nutrition, and phenotype. Studies in human and animal models have indicated the importance of the optimal levels of methyl donors on brain health and behavior across the lifespan. Imbalances in the levels of these micronutrients during critical periods of brain development have been linked to epigenetic alterations in the expression of genes that regulate normal brain function. We present studies that support the link between imbalances in the levels of methyl donors, epigenetic alterations, and stress-related disorders. Appropriate levels of these micronutrients should then be monitored at all stages of development for a healthier brain.

Danhong injection alleviates cerebral ischemia-reperfusion injury by inhibiting autophagy through miRNA-132-3p/ATG12 signal axis

ETHNOPHARMACOLOGICAL RELEVANCE

Danhong injection (DHI) is a renowned traditional Chinese medicine often used clinically to treat cardiovascular and cerebrovascular diseases. Studies have shown that DHI can significantly alter microRNA (miRNA) expression in the brain tissue. Therefore, exploring specific miRNAs' regulatory mechanisms during treatment with DHI is essential.

AIM OF THE STUDY

To investigate DHI's regulatory mechanism on cerebral autophagy in rats with cerebral ischemia-reperfusion injury (CIRI).

MATERIAL AND METHODS

Rats were randomly divided into the sham, middle cerebral artery occlusion (MCAO) model, and DHI-treatment groups. The extent of brain damage was evaluated using triphenyl tetrazolium chloride and hematoxylin-eosin staining. Hippocampal cell autophagy was observed using transmission electron microscopy. Autophagy-related proteins were analyzed using western blotting. Differentially expressed miRNAs were screened using high-throughput and real-time quantitative reverse transcription PCR. The relationship between miR-132-3p and ATG12 was confirmed using a dual-luciferase assay. The miR-132-3p mimics and inhibitors were transfected into PC12 cells subjected to oxygen-glucose deprivation (OGD) in vitro and MCAO model rats in vivo.

RESULTS

DHI significantly altered the miRNA expression profile in rat brain tissues. The pathological changes in the brain tissues were improved, and the autophagic hippocampal cell vehicles were significantly reduced after DHI treatment. miRNA-132-3p, one of the miRNAs with a significantly different expression, was screened. Kyoto Encyclopedia of Genes and Genomes signal pathway analysis showed that its target genes were closely related to autophagy. Western blotting revealed that the p-PI3K, p-AKT, and mTOR expression increased significantly; AMPK, ULK1, ATG12, ATG16L1, and LC3II/I were downregulated in the DHI group. Dual-luciferase reporter gene experiments showed that miRNA-132-3p could target the ATG12 3'-UTR region directly. In vitro, miRNA-132-3p had a protective effect on OGD/R-induced oxidative stress injury in PC12 cells, improving cell viability, and affecting the expression of autophagy pathway-related proteins. In vivo transfection experiments showed that miR-132-3p could regulate ATG12 expression in CIRI rats' lateral brain tissue, affecting the autophagy signaling pathway. miR-132-3p overexpression reduces CIRI-induced autophagy and protects neurons.

CONCLUSION

This study showed that DHI inhibits neuronal autophagy after cerebral ischemia-reperfusion. This may have resulted from miR-132-3p targeting ATG12 and regulating the autophagy signaling pathway protein expression.

MicroRNA-21 and microRNA-148a affects PTEN, NO and ROS in canine leishmaniasis

Canine Visceral leishmaniasis (CanL) poses a severe public health threat in several countries. Disease progression depends on the degree of immune response suppression. MicroRNAs (miRs) modulate mRNA translation into proteins and regulate various cellular functions and pathways associated with immune responses. MiR-21 and miR-148a can alter the parasite load and M1 macrophages are the principal cells in dogs' leishmanicidal activity. A previous study found increased miR-21 and miR-148a in splenic leukocytes (SL) of dogs with CanL using microarray analysis and in silico analysis identified PTEN pathway targets. PTEN is involved in the immune regulation of macrophages. We measured PTEN and the production of reactive oxygen species (ROS) and nitric oxide (NO) before and after transfection SLs of dogs with CanL with mimic and inhibition of miR-21 and miR-148a. PTEN levels increased, NO and ROS decreased in SLs from dogs with CanL. Inhibition of miRNA-21 resulted in PTEN increase; in contrast, PTEN decreased after miR-148a inhibition. Nitrite (NO₂) levels increased after transfection with miR-21 inhibitor but were decreased with miR-148a inhibitor. The increase in miR-21 promoted a reduction in ROS and NO levels, but miR-148a inhibition increased NO and reduced ROS. These findings suggest that miR-21 and miR-148a can participate in immune response in CanL, affecting PTEN, NO, and ROS levels.

The Biogenesis of miRNAs and Their Role in the Development of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects upper and lower motor neurons. As there is no effective treatment for ALS, it is particularly important to screen key gene therapy targets. The identifications of microRNAs (miRNAs) have completely changed the traditional view of gene regulation. miRNAs are small noncoding single-stranded RNA molecules involved in the regulation of post-transcriptional gene expression. Recent advances also indicate that miRNAs are biomarkers in many diseases, including neurodegenerative diseases. In this review, we summarize recent advances regarding the mechanisms underlying the role of miRNAs in ALS pathogenesis and its application to gene therapy for ALS. The potential of miRNAs to target diverse pathways opens a new avenue for ALS therapy.

Silencing microRNA‑29b‑3p expression protects human trabecular meshwork cells against oxidative injury via upregulation of RNF138 to activate the ERK pathway

In recent years, the potential involvement of numerous microRNAs (miRNAs) in glaucoma has been widely reported. However, the role of microRNA-29b-3p (miR-29b-3p) in the pathogenesis of glaucoma remains unknown. This study aimed to explore the biological role and regulatory mechanism of miR-29b-3p in the oxidative injury of human trabecular meshwork (HTM) cells induced by H₂O₂ stimulation. By establishing a glaucoma rat model, the effects of miR-29-3p in glaucoma were detected in vivo. Our findings demonstrated that miR-29b-3p was upregulated in a glaucoma model and antagomiR-29b-3p alleviated the symptoms of glaucoma. In vitro assays revealed that miR-29b-3p expression was significantly upregulated in HTM cells with H₂O₂ stimulation. Knockdown of miR-29b-3p alleviated H₂O₂-induced oxidative injury in HTM cells by promoting cell viability, and inhibiting cell apoptosis, reactive oxygen species generation and extracellular matrix production. Subsequently, it was found that E3 ubiquitin-protein ligase RNF138 (RNF138) was a downstream target of miR-29b-3p. RNF138 expression was downregulated in HTM cells with H₂O₂ stimulation. RNF138 knockdown significantly rescued the protective effect of miR-29b-3p inhibitor on HTM cells under oxidative injury. Additionally, miR-29b-3p silencing activated the ERK pathway via upregulating RNF138. Collectively, silencing of miR-29b-3p protected HTM cells against oxidative injury by upregulation of RNF138 to activate the ERK pathway.

Neuroinflammation in Ischemic Stroke: Focus on MicroRNA-mediated Polarization of Microglia

Ischemic stroke is one of the most common causes of death and disability worldwide. Neuroinflammation is a major pathological event involved in the process of ischemic injury and repair. In particular, microglia play a dual role in neuroinflammation. During the acute phase of stroke onset, M2 microglia are the dominant phenotype and exert protective effects on neuronal cells, whereas permanent M1 microglia contribute to prolonged inflammation and are detrimental to brain tissue. Emerging evidence indicates that microRNAs (miRNAs) may have regulatory effects on microglia-associated inflammation. Thus, we briefly reviewed the dynamic response of microglia after a stroke and assessed how specific miRNAs affect the behavior of reactive microglia. We concluded that miRNAs may be useful novel therapeutic targets to improve stroke outcomes and modulate neuroinflammation.

Potential role of miR-214 in β-catenin gene expression within hepatocellular carcinoma

MicroRNAs (miRNAs) are important gene regulators whose dysregulations can be involved in tumorigenesis. β-catenin, the main agent in the Wnt/β-catenin pathway, controls various genes and its over-expression has been discovered in different kinds of cancers including Hepatocellular Carcinoma (HCC). Extensive research demonstrated that the Wnt signaling is one of the major affected pathways in HCC. This study aimed to find miRNA targeting β-catenin gene by bioinformatic approaches and confirm this correlation to propose new therapeutic targets for HCC. Prediction of miRNAs targeting 3'-Untranslated Regions (UTR) of β-catenin mRNA, were done using different types of credible bioinformatic databases. The luciferase assay was also recruited for further confirmation of the bioinformatic predictions. In the first step, the expression of β-catenin was assessed in the HepG2 cell line by real-time PCR technique. Next, transduction of HepG2 cells were done by lentiviral vectors containing the desired miRNA. Then, the expression level of miRNA and the β-catenin gene were evaluated. Based on the results obtained from different bioinformatic databases, miR-214 was selected as the potential miRNA with the highest probability in targeting β-catenin. Furthermore, Luciferase assay results confirmed the accuracy of our bioinformatic prediction. In line with our hypothesis, after the overexpression of miR-214 in HepG2 cells, β-catenin gene expression was reduced significantly. Gathered results indicate the miRNAs role in the down-regulation of their target genes. Hence, the results propose that miR-214 can prevent HCC development by suppressing β-catenin and may supply a newfound approach towards HCC therapy in humans.

Serum Profile of microRNAs Linked to Bone Metabolism During Sequential Treatment for Postmenopausal Osteoporosis

CONTEXT

Serum expression of microRNAs (miRs) related to bone metabolism is affected by antiosteoporotic treatment.

OBJECTIVE

To investigate the effect of sequential treatments on miR expression in postmenopausal women with osteoporosis.

DESIGN

Observational, open label, nonrandomized clinical trial.

SETTING

A single-center outpatient clinic.

PATIENTS AND INTERVENTIONS

Denosumab (Dmab) was administered for 12 months in 37 women who were treatment-naïve (naïve group) (n = 11) or previously treated with teriparatide (TPTD group) (n = 20) or zoledronate (ZOL group) (n = 6).

MAIN OUTCOME MEASURES

Relative serum expression of miRs linked to bone metabolism at 3 and 6 months of Dmab treatment.

RESULTS

Baseline relative expression of miR-21a-5p, miR-23a-3p, miR-29a-3p, and miR-338-3p was higher in the TPTD group, while the relative expression of miR-21a-5p was lower in the ZOL group compared to the naïve group. Dmab decreased the relative expression of miR-21a-5p at 3 months (fold change [FC] 0.43, P < 0.001) and 6 months (FC 0.34, P < 0.001), and miR-338-3p and miR-2861 at 6 months (FC 0.31, P = 0.041; FC 0.52, P = 0.016, respectively) in the whole cohort. In subgroup analyses, Dmab decreased the relative expression of miR-21a-5p, miR-29a-3p, miR-338-3p, and miR-2861 at 3 months (FC 0.13, P < 0.001; FC 0.68, P = 0.044; FC 0.46, P = 0.012; and FC 0.16, P < 0.001, respectively) and 6 months (FC 0.1, P < 0.001; FC 0.52, P < 0.001; FC 0.04, P = 0.006; and FC 0.2, P < 0.001, respectively) only within the TPTD group.

CONCLUSIONS

TPTD treatment potentially affects the expression of the pro-osteoclastogenic miR-21a-5p and miRs related to the expression of osteoblastic genes RUNX2 (miR23a-3p), COL1 (miR-29a-3p), and HDAC5 (miR-2861), while sequential treatment with Dmab acts in the opposite direction.

New possible pharmacological targets for statins and ezetimibe

Statin therapy is the gold standard in the treatment of dyslipidemia. Understanding the mechanisms of action of these drugs provides an opportunity to define new therapeutic goals for pharmacotherapy in patients with atherosclerotic lesions. The present review indicates the existence of previously unknown therapeutic targets for statins, such as Krüppel-like Factor 2 (KLF-2), Cystathionine γ lyase (CSE) and the microRNA regulating eNOS activity and synthesis; nuclear PXR receptor and EB transcription factor regulating Inflammasome NLRP3 activity; the Dickkopf-related protein 1 (DKK-1), which inhibits the WNT signalling pathway; the peroxisome proliferator-activated receptor (PPAR-γ) in vascular smooth muscle cells (VSMCs), which regulates the cell cycle, and the ERK5-Nrf2 pathway, which reduces the level of harmful advanced glycation end-products (AGE) in VSMCs during diabetic vasculopathy. Importantly, our review includes a number of promising discoveries, specifically those related to the effects of miR-221, miR-222 and miR-27b on the structure, synthesis and activity of eNOS, such as microRNA-based therapies, which offer promise in future targeted therapies. In contrast to numerous experiments confirming the pleiotropic effect of statins, there is still insufficient evidence on the pleiotropic effect of ezetimibe, which goes beyond its basic inhibitory effect on intestinal cholesterol absorption. However, recent studies indicate that this effect is limited to inhibiting macrophage migration, decreasing VCAM-1 expression and reducing the levels of reactive oxygen species. Defining new therapeutic goals for pharmacotherapy in patients with atherosclerotic lesions and ensuring effective treatment of dyslipidemia and its associated cardiovascular complications requires a thorough understanding of both the mechanisms of action of these drugs and of atherosclerosis itself.

MicroRNA-214 protects L6 skeletal myoblasts against hydrogen peroxide-induced apoptosis

MicroRNAs (miRNAs) have been reported as key gene regulators, and they control many fundamental biological processes. Previously, we demonstrated that miR-214 had a protective effect against myocardial apoptosis and myocardial fibrosis. In this study, we sought to investigate the expression of miR-214 in L6 skeletal myoblast (SKM), the regulatory effect of miR-214 on hydrogen peroxide (H₂O₂) induced cell apoptosis and the underlying mechanisms of the antiapoptotic effect. MiR-214 expression was up-regulated by H₂O₂ in a dose and time-dependent manner in L6 SKMs. To investigate the regulatory effects of miR-214 on L6 SKM, both gain-of-function and loss-of-function approaches were applied. The results showed that miR-214 improved cell survival and inhibited cell apoptosis, and blockage of miR-214 abrogated the protective effect on cell survival and resistance to apoptosis. Phosphatase and tensin homolog (PTEN) was negatively regulated by miR-214, and PTEN inhibitor obviously reversed the effect of miR-214 blockage on enhancing cell apoptosis. In addition, miR-214 up-regulated antiapoptotic protein Bcl-2, down-regulated proapoptotic protein Bax, prevented release of cytochrome c and inhibited caspase-3 activation. In summary, H₂O₂-induced injury increases miR-214 expression in L6 SKM, and miR-214 contributes to the protection of L6 SKM against apoptosis via lowering PTEN and subsequently inhibiting the mitochondrial-mediated caspase-dependent apoptotic signaling pathway.

miR-223 induces retinal ganglion cells apoptosis and inflammation via decreasing HSP-70 in vitro and in vivo

PURPOSE

Glaucoma is an eye disease characterized by the loss of peripheral vision, high pressure in the eye, optic nerve damage, and the loss of peripheral vision due to loss of retinal ganglion cells (RGCs). A number of miRNA have been detected in the pathogenesis of glaucoma. The paper was to focus on the miR-223 in RGCs apoptosis and inflammation, and investigated the possible mechanisms in vitro and in vivo.

MATERIALS AND METHODS

After miR-223 inhibitor and mimics transfected into RGCs, the expression of miR-223 was detected by QRT-PCR, cell proliferation were performed by CCK-8 and EdU assays, cell apoptosis were measured by flow cytometer and TUNEL assays, apoptosis and inflammation -related proteins were detected by western blot, and whether miR-223 target to HSP-70 was detected by Luciferease reporter assay. Moreover, the effects si-HSP-70 on RGCs or RGCs transfected with miR-223 inhibitor were detected. In vivo study. New Zealand White rabbits (20 females) were used to detect the effect of miR-223 on the rabbit glaucoma model induced by injection of carbomer.

RESULTS

CCK-8 and EdU assays demonstrated that miR-223 mimics decreased RGCs proliferation. FITC-Annexin V/PI Apoptosis and TUNEL assays showed that miR-223 mimics induced RGCs apoptosis. Western blot revealed that miR-223 mimics enhanced the expression of relative apoptosis and inflammation factors. Further, we demonstrated that miR-223 could inhibit cell proliferation, induce cell apoptosis as well as inflammation by targeting HSP-70 in RGCs. Moreover, the results were confirmed in rabbit glaucoma model.

CONCLUSIONS

In summary, miR-223 plays a vital role in RGCs by regulating HSP-70 expression, and the new therapeutic strategy might potentially contribute to benefit glaucoma treatment.

Effect of HIF-1α/miR-10b-5p/PTEN on Hypoxia-Induced Cardiomyocyte Apoptosis

Background Few reports have addressed the mechanism by which microRNA miR-10b-5p regulates post-myocardial infarction (post-MI) cardiomyocyte apoptosis under hypoxic conditions. Methods and Results C57BL/6 mice underwent surgical ligation of the left anterior descending artery to create an MI or ischemia/reperfusion animal model. The expression of miR-10b-5p, PTEN (phosphatase and tensin homolog), and HIF-1α (hypoxia-inducible factor 1α) was detected in infarct border zone tissues at various time points. After precordial injections of the negative control or miR-10b-5p, overexpression lentiviruses were made in the areas surrounding the MI sites at 1 week, and myocardial infarct size, cardiac function, and cardiomyocyte apoptosis were examined. A miR-10b-5p mimic was transfected into primary mouse cardiomyocytes to analyze its effects on cardiomyocyte apoptosis and PTEN expression. Meanwhile, PTEN as a target of miR-10b-5p was verified via luciferase reporter gene assays. Cotransfection of miR-10b-5 and PTEN verified the relationship between miR-10b-5 and PTEN. Under hypoxic stress, the expression of HIF-1α and miR-10b-5p was examined. The results showed that miR-10b-5p expression was markedly reduced in the infarct border zone. Overexpression of miR-10b-5p in the murine model of MI significantly reduced MI size, improved cardiac function, and inhibited apoptosis. Overexpression of miR-10b-5p in vitro antagonized hypoxia-induced cardiomyocyte apoptosis and specifically inhibited the expression of the apoptosis-related gene PTEN, but overexpression of PTEN weakened these effects. We also found that hypoxia-induced accumulation of HIF-1α resulted in decreased expression of miR-10b-5p. Interfering with the activation of the HIF-1α signaling pathway promoted Pri-miR-10b and miR-10b-5p expression and inhibited PTEN expression. Conclusions MicroRNA miR-10b-5p antagonizes hypoxia-induced cardiomyocyte apoptosis, indicating that miR-10b-5p may serve as a potential future clinical target for the treatment of MI.

Overexpression of miR-671-5p indicates a poor prognosis in colon cancer and accelerates proliferation, migration, and invasion of colon cancer cells

Purpose

Colon cancer is one of the common malignancies worldwide, and many genes, including microRNAs (miRNAs), have been demonstrated that associated with progression of various diseases, including cancers. The aim of this study is to investigate the potential role of miR-671-5p in colon cancer.

Patients and methods

Reverse transcription-quantitative polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of miR-671-5p in 115 paired colon cancer tissues and adjacent normal tissues, as well as in colon cancer cells. Kaplan-Meier curve and Cox regression analyses were used to estimate the prognostic significance of miR-671-5p in colon cancer. CCK-8 assay, colony-formation assay, Transwell migration and invasion assays were used to evaluate the effects of miR-671-5p on cell proliferation, migration, and invasion in colon cancer.

Results

We found that miR-671-5p expression was increased in colon cancer tissues and cell lines. Overexpression of miR-671-5p was found associated with lymph node metastasis, TNM stage, and poor overall survival of patients with colon cancer. By exploiting miR-671-5p mimics and inhibitors, miR-671-5p overexpression significantly increased cell proliferation, migration, and invasion, while downregulation of miR-671-5p inhibited proliferation, migration, and invasion of colon cancer cells.

Conclusion

Taken together, miR-671-5p may act as an oncogene in colon cancer and promote proliferation, migration, and invasion of colon cancer cells by targeting TRIM67. And it may be a promising prognostic biomarker and therapeutic application for colon cancer treatment.

Captopril and Spironolactone Can Attenuate Diabetic Nephropathy in Wistar Rats by Targeting microRNA-192 and microRNA-29a/b/c

Diabetes mellitus is a complicated metabolic disease characterized by hyperglycemia. Diabetic nephropathy (DN) is a progressive kidney disease, which results in mortality in diabetic patients. The present study was designed to investigate the effect of applying spironolactone (S), captopril (C), and their combination (S+C) on some renal performance indices and microRNAs' (miRNAs) expression. A total of 35 two-month-old male Wistar rats were provided for the study. Intraperitoneal injection of freshly dissolved streptozotocin (60 mg/kg) in cold citrate buffer was used to induce diabetes. Blood samples were examined through calorimetry to assess serum concentrations of glucose, blood urea nitrogen (BUN), and creatinine. To measure the microalbuminuria and transforming growth factor-β (TGF-β) levels and to evaluate the miRNAs expression levels of the kidney tissue, the ELISA method and the real-time PCR were used. The obtained results serve as in vivo evidence for the positive relationship between miR-192 and TGF-β levels in the DN rats. A significant increase and decrease were found for miR-29a/b/c and the miR-192 expression of DN after treatment with S, C, and S+C. TGF-β levels and microalbuminuria of diabetic rats also increased. The results obtained from this research study suggest that S, C, and S + C can improve DN by targeting miR-192 and miR-29 family and changing their expression. These findings suggest that miR-192 and miRs-29a/b/c can be potential targets for DN remediation.

MicroRNA-124: An emerging therapeutic target in cancer

MicroRNAs (miRNAs) are noncoding single‐stranded RNAs, approximately 20‐24 nucleotides in length, known as powerful posttranscriptional regulators. miRNAs play important regulatory roles in cellular processes by changing messenger RNA expression and are widely involved in human diseases, including tumors. It has been reported in the literature that miRNAs have a precise role in cell proliferation, programmed cell death, differentiation, and expression of coding genes. MicroRNA‐124 (miR‐124) has reduced exparession in various human neoplasms and is believed to be related to the occurrence, development, and prognosis of malignant tumors. In our review, we focus on the specific molecular functions of miR‐124 and the downstream gene targets in major cancers, which provide preclinical evidence for the treatment of human cancer. Although some obstacles exist, miR‐124 is still attracting intensive research focus as a promising and effective anticancer weapon.

Expression Pattern of microRNAs, miR-21, miR-155 and miR-338 in Patients with Type 1 Diabetes

BACKGROUND

Type 1 diabetes (T1D) is a multifactorial disease identified by a deficiency in the production of insulin. MicroRNAs (miRNAs) are identified as important epigenetic regulators in T1D. Many studies highlight the differential expression of these small non-coding molecules in the pathogenesis of T1D.

AIM OF THE STUDY

In the present study, the expression pattern of miR-21, miR-155 and miR-338 were analyzed in the peripheral blood mononuclear cells (PBMCs) of T1D patients compared to healthy controls.

METHODS

The expression levels of miR-21, miR-155 and miR-338 were measured in the PBMCs of 30 T1D patients and 11 healthy controls by real time PCR method. The final results were statistically analyzed and ROC curves were created for miRNAs with significant differential expression.

RESULTS

Both miR-155 (p value: 0.021) and miR-21 (p value: 0.05) were upregulated in the PBMCs of T1D patients compared to healthy controls. There was no significant difference in the expression level of miR-338 between patients and controls. Furthermore, ROC curve analysis was performed for miR-21 (AUC: 0.65) and miR-155 (AUC: 0.73) which suggests the potential role of miR-155 as a biomarker in T1D patients. Using integrative computational analysis, a number of dysregulated miR155-mRNA and miR21-mRNA interactions were also suggested.

CONCLUSION

Our findings suggest the significant association between the expression levels of miR-21 and miR-155 with T1D. In addition, miR-155 (AUC: 0.73) could be considered as a possible biomarker to track disease in T1D patients.

MicroRNA-7b attenuates ischemia/reperfusion-induced H9C2 cardiomyocyte apoptosis via the hypoxia inducible factor-1/p-p38 pathway

OBJECTIVE

MicroRNAs (miRNAs) have been shown to play crucial roles in the occurrence, development, and treatment of many cardiovascular diseases. Coronary heart disease (CAD)-related miRNAs are still a growing research area. miR-7b was reported to be downregulated in acute myocardial infarction (AMI) myocardium tissues. However, it remains largely unknown whether miR-7b is involved in the pathogenesis and progression of the AMI ischemia/reperfusion (I/R) injury.

METHODS

Male C57BL/6 J mice and H9C2 cells were used as models in this study. Masson staining, real-time polymerase chain reaction, Western blot analysis, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling immunofluorescence staining assays were performed to detect the related indicators in the study. SPSS 17.0 software was used to calculate the experimental data.

RESULTS

The results showed that miR-7b expression is downregulated after I/R in mice, and miR-7b could inhibit apoptosis in I/R-induced H9C2 cells via upregulating hypoxia-inducible factor 1a (HIF1a). The inhibitory effect of miR-7b on I/R-induced apoptosis in H9C2 cells was blocked by HIF1a silencing. In addition, our data suggested that the p-P38 pathway may be involved in the role of miR-7 in I/R-induced H9C2 cell apoptosis.

CONCLUSION

We confirmed that the overexpression of miR-7b inhibits I/R-induced apoptosis in H9C2 cells by targeting the HIF1a/p-P38 pathway. Our findings not only demonstrate the potential role of miR-7b in attenuating I/R-induced apoptosis but also provide a new insight into the better prevention of the I/R injury by mediating HIF-1 and p-P38.

The long noncoding RNA NORAD enhances the TGF-β pathway to promote hepatocellular carcinoma progression by targeting miR-202-5p

Hepatocellular carcinoma (HCC) is one of the most fatal cancers with common features of invasion and metastasis. Recent evidence indicate that the long noncoding RNA NORAD is a potential oncogene and is significantly upregulated in several cancers. However, the general biological role and clinical value of NORAD in HCC remains unknown. Here, NORAD expression was measured in 29 paired tumor and paratumor tissues via quantitative real-time polymerase chain reaction (qPCR). The effects of NORAD on HCC cell malignant potential were investigated via NORAD overexpression and knockdown both in vitro and in vivo. The mechanism of competitive endogenous RNAs (ceRNAs) was acquired and identified by bioinformatics analyses and luciferase assays. Moreover, the impact of NORAD level on the transforming growth factor β (TGF-β) pathway was further determined by qPCR. We found that HCC tissues had a high level of NORAD compared with the paratumor tissues, and NORAD upregulation was associated with the shorter overall survival of patients with HCC. Furthermore, NORAD overexpression was demonstrated to promote HCC cell migration and invasion. Mechanically, NORAD might function as a ceRNA to regulate miR-202-5p, which served as a tumor-suppressing microRNA via the TGF-β pathway. We address that NORAD has a tumor-promoting effect in HCC and describes a novel mechanism whereby NORAD regulates the TGF-β pathway as a ceRNA of Homo sapiens (hsa)-miR-202-5p.

MiR-214 is an important regulator of the musculoskeletal metabolism and disease

MiR-214 belongs to a family of microRNA (small, highly conserved noncoding RNA molecules) precursors that play a pivotal role in biological functions, such as cellular function, tissue development, tissue homeostasis, and pathogenesis of diseases. Recently, miR-214 emerged as a critical regulator of musculoskeletal metabolism. Specifically, miR-214 can mediate skeletal muscle myogenesis and vascular smooth muscle cell proliferation, migration, and differentiation. MiR-214 also modulates osteoblast function by targeting specific molecular pathways and the expression of various osteoblast-related genes; promotes osteoclast activity by targeting phosphatase and tensin homolog (Pten); and mediates osteoclast-osteoblast intercellular crosstalk via an exosomal miRNA paracrine mechanism. Importantly, dysregulation in miR-214 expression is associated with pathological bone conditions such as osteoporosis, osteosarcoma, multiple myeloma, and osteolytic bone metastasis of breast cancer. This review discusses the cellular targets of miR-214 in bone, the molecular mechanisms governing the activities of miR-214 in the musculoskeletal system, and the putative role of miR-214 in skeletal diseases. Understanding the biology of miR-214 could potentially lead to the development of miR-214 as a possible biomarker and a therapeutic target for musculoskeletal diseases.

Prediction of microRNA-binding residues in protein using a Laplacian support vector machine based on sequence information

The identification of microRNA (miRNA)-binding protein residues significantly impacts several research areas, including gene regulation and expression. We propose a method, PmiRBR, which combines a novel hybrid feature with the Laplacian support vector machine (LapSVM) algorithm to predict miRNA-binding residues in protein sequences. The hybrid feature is constituted by secondary structure, conservation scores, and a novel feature, which includes evolutionary information combined with the physicochemical properties of amino acids. Performance comparisons of the various features indicate that our novel feature contributes the most to prediction improvement. Our results demonstrate that PmiRBR can achieve 85.96% overall accuracy, with 43.89% sensitivity and 90.56% specificity. PmiRBR significantly outperforms other approaches at miRNA-binding residue prediction.

Changes of Circulating MicroRNAs in Response to Treatment With Teriparatide or Denosumab in Postmenopausal Osteoporosis

CONTEXT

Expression of microRNAs (miRs) related to bone metabolism in the serum may be affected by antiosteoporotic treatment.

OBJECTIVE

To investigate the effect of two antiosteoporotic agents with opposite effects on bone metabolism on miR expression profile in the serum.

DESIGN

Observational, open label, nonrandomized clinical trial.

SETTING

The outpatient clinics for Metabolic Bone Diseases of 424 General Military Hospital, Thessaloniki, Greece.

PATIENTS AND INTERVENTIONS

Postmenopausal women with low bone mass were treated with either teriparatide (TPTD; n = 30) or denosumab (n = 30) for 12 months.

MAIN OUTCOME MEASURES

Changes in the serum expression of selected miRs linked to bone metabolism at 3 and 12 months of treatment. Secondary measurements: associations of measured miRs with changes in bone mineral density (BMD) at 12 months and the bone turnover markers (BTMs) C-terminal cross-linking telopeptide of type I collagen and procollagen type I N-terminal propeptide at 3 and 12 months.

RESULTS

We found significantly decreased relative expression of miR-33-3p at 3 months (P = 0.03) and of miR-133a at 12 months (P = 0.042) of TPTD treatment. BMD values at 12 months of TPTD treatment were significantly and inversely correlated with miR-124-3p expression at 3 months (P = 0.008). Relative expression of miR-24-3p and miR-27a was correlated with changes in BTMs during TPTD treatment and of miR-21-5p, miR-23a-3p, miR-26a-5p, miR-27a, miR-222-5p, and miR-335-5p with changes in BTMs during denosumab treatment.

CONCLUSIONS

Circulating miRs are differentially affected by treatment with TPTD and denosumab. TPTD affects the relative expression of miRs related to the expression of RUNX-2 (miR-33) and DKK-1 gene (miR-133).

The Potential Role of miRNAs as New Biomarkers for Osteoporosis

Osteoporosis is the most common metabolic bone disorder affecting up to 40% of postmenopausal women, characterized by a reduction in bone mass and strength leading to bone fragility and fractures. Despite the available tools for diagnosis and stratification of a fracture risk, bone loss occurs insidiously and osteoporosis is often diagnosed after the first fracture has occurred, with important health-related outcomes. Therefore, the need of markers that could efficiently diagnose bone fragility and osteoporosis is still necessary. Over the past few years, novel studies have focused on miRNAs, small noncoding RNAs that are differentially expressed in many pathological conditions, making them attractive biomarkers. To date, the role of miRNAs in bone disorders remains in great part unclear. In particular, limited and partly conflicting information is available concerning their use as potential biomarkers for osteoporosis, due to differences in patient selection, type of samples, and analytical methods. Despite these limits, concordant information about some specific miRNAs is now arising, making likely their use as additional tools to stratify the risk of osteoporosis and possibly fractures. In this review, we summarize the most relevant studies concerning circulating miRNAs differentially expressed in osteoporotic patients along with their function in bone cells and bone turnover.

Regulatory Small and Long Noncoding RNAs in Brite/Brown Adipose Tissue

Brite/brown adipose tissue (BAT) is a thermogenic tissue able to dissipate energy via non-shivering thermogenesis. It is naturally activated by cold and has been demonstrated to increase thermogenic capacity, elevate energy expenditure, and to ultimately contribute to fat mass reduction. Thus, it emerges as novel therapeutic concept for pharmacological intervention in obesity and other metabolic disorders. Therefore, the comprehensive understanding of the regulatory network in thermogenic adipocytes is in demand.The surprising findings that (1) all human protein-coding genes make up not more than 2% of our genome, (2) organismal complexity goes well along with the percentage of nonprotein-coding sequences, and that (3) three quarters of our genome are pervasively transcribed, provide evidence that noncoding RNAs (ncRNAs) are not junk, but a significant and even predominant part of our transcriptome representing a treasure chest worth retrieving regulatory determinants in biological processes and diseases.In this chapter, the impact of regulatory small and long ncRNAs (lncRNAs) in particular microRNAs and lncRNAs on BAT formation and metabolic function and their involvement in physiological and pathological conditions has been reviewed.

Small non coding RNAs in adipocyte biology and obesity

Obesity has reached epidemic proportions world-wide and constitutes a substantial risk factor for hypertension, type 2 diabetes, cardiovascular diseases and certain cancers. So far, regulation of energy intake by dietary and pharmacological treatments has met limited success. The main interest of current research is focused on understanding the role of different pathways involved in adipose tissue function and modulation of its mass. Whole-genome sequencing studies revealed that the majority of the human genome is transcribed, with thousands of non-protein-coding RNAs (ncRNA), which comprise small and long ncRNAs. ncRNAs regulate gene expression at the transcriptional and post-transcriptional level. Numerous studies described the involvement of ncRNAs in the pathogenesis of many diseases including obesity and associated metabolic disorders. ncRNAs represent potential diagnostic biomarkers and promising therapeutic targets. In this review, we focused on small ncRNAs involved in the formation and function of adipocytes and obesity.

Functional Implications of miR-19 in the Migration of Newborn Neurons in the Adult Brain

Altered microRNA profiles have been implicated in human brain disorders. However, the functional contribution of individual microRNAs to neuronal development and function is largely unknown. Here, we report biological functions for miR-19 in adult neurogenesis. We determined that miR-19 is enriched in neural progenitor cells (NPCs) and downregulated during neuronal development in the adult hippocampus. By manipulating miR-19 in NPCs for gain- and loss-of-function studies, we discovered that miR-19 regulates cell migration by directly targeting Rapgef2. Concordantly, dysregulation of miR-19 in NPCs alters the positioning of newborn neurons in the adult brain. Furthermore, we found abnormal expression of miR-19 in human NPCs generated from schizophrenic patient-derived induced pluripotent stem cells (iPSCs) that have been described as displaying aberrant migration. Our study demonstrates the significance of posttranscriptional gene regulation by miR-19 in preventing the irregular migration of adult-born neurons that may contribute to the etiology of schizophrenia.

SQLE induces epithelial-to-mesenchymal transition by regulating of miR-133b in esophageal squamous cell carcinoma

Increasing evidence suggests that microRNAs, which control gene expression at the post-transcriptional level, are aberrantly expressed in cancers and play significant roles in carcinogenesis and cancer progression. In this study, we show differential miR-133b down-expression in human esophageal squamous cell carcinoma (ESCC) cells and tissues. In addition, squalene epoxidase (SQLE), a key enzyme of cholesterol synthesis, is identified as the direct downstream target gene of miR-133b by luciferase gene reporter assay. Furthermore, ectogenic miR-133b expression and SQLE knockdown can inhibit proliferation, invasion, and metastasis, and diminish epithelial-to-mesenchymal transition (EMT) traits of ESCC in vitro, implying that miR-133b-dependent SQLE can induce tumorigenicity and that SQLE is an EMT inducer. Xenograft experiment results also proved the biological function of SQLE in vivo. Therefore, we conclude that miR-133b-dependent SQLE plays a critical role in the potential metastasis mechanisms in ESCC.

MicroRNA Expression Profiling Using Agilent One-Color Microarray

MicroRNA (miRNA) expression profiling is an important tool to identify miRNA regulation in physiological or pathological states. This technique has a large number of molecular diagnostic applications, including in cancer, cardiovascular and autoimmune diseases, and forensics. To date, a multitude of high-throughput genomic approaches have been developed. Here, we focus on miRNA expression profiling by microarray using SurePrint technology, providing a description of both the workflow and methods for expression profiling by Agilent One-Color Microarray.

Traceable microRNA-124 loaded nanoparticles as a new promising therapeutic tool for Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disorder characterized by the selective degeneration of the nigrostriatal dopaminergic pathway, is a major socio-economic burden in modern society. While there is presently no cure for PD, enhancing the number of neural stem cells (NSCs) and/or stimulating their differentiation into new neurons are promising therapeutic strategies. Many proneurogenic factors have been implicated in controlling NSCs activity, including the microRNA (miR)-124. However, current strategies described for the intracellular delivery of miR involve mostly unspecific or inefficient platforms. In Saraiva et al. we developed miR-124 loaded nanoparticles (NPs) able to efficiently deliver miR-124 into neural stem/progenitor cells and boost neuronal differentiation and maturation in vitro. In vivo, the intracerebroventricular injection of miR-124 NPs increased the number of new neurons in the olfactory bulb of healthy and 6-hydroxidopamine (6-OHDA) lesioned mice, a model for PD. Importantly, miR-124 NPs enhanced the migration of new neurons into the 6-OHDA lesioned striatum, culminating in motor function improvement. Given the recent advent of clinical trials for miR-based therapies and the theranostic applications of our NPs, we expect to support the clinical translation of our delivery platform in the context of PD and other neurodegenerative diseases which may benefit from enhancing miR levels.

Let-7i-5p represses brite adipocyte function in mice and humans

In response to cold or β3-adrenoreceptor stimulation brown adipose tissue (BAT) promotes non-shivering thermogenesis, leading to energy dissipation. BAT has long been thought to be absent or scarce in adult humans. The recent discovery of thermogenic brite/beige adipocytes has opened the way to development of novel innovative strategies to combat overweight/obesity and associated diseases. Thus it is of great interest to identify regulatory factors that govern the brite adipogenic program. Here, we carried out global microRNA (miRNA) expression profiling on human adipocytes to identify miRNAs that are regulated upon the conversion from white to brite adipocytes. Among the miRNAs that were differentially expressed, we found that Let-7i-5p was down regulated in brite adipocytes. A detailed analysis of the Let-7i-5p levels showed an inverse expression of UCP1 in murine and human brite adipocytes both in vivo and in vitro. Functional studies with Let-7i-5p mimic in human brite adipocytes in vitro revealed a decrease in the expression of UCP1 and in the oxygen consumption rate. Moreover, the Let-7i-5p mimic when injected into murine sub-cutaneous white adipose tissue inhibited partially β3-adrenergic activation of the browning process. These results suggest that the miRNAs Let-7i-5p participates in the recruitment and the function of brite adipocytes.

MicroRNA-124 loaded nanoparticles enhance brain repair in Parkinson's disease

Modulation of the subventricular zone (SVZ) neurogenic niche can enhance brain repair in several disorders including Parkinson's disease (PD). Herein, we used biocompatible and traceable polymeric nanoparticles (NPs) containing perfluoro-1,5-crown ether (PFCE) and coated with protamine sulfate to complex microRNA-124 (miR-124), a neuronal fate determinant. The ability of NPs to efficiently deliver miR-124 and prompt SVZ neurogenesis and brain repair in PD was evaluated. In vitro, miR-124 NPs were efficiently internalized by neural stem/progenitors cells and neuroblasts and promoted their neuronal commitment and maturation. The expression of Sox9 and Jagged1, two miR-124 targets and stemness-related genes, were also decreased upon miR-124 NP treatment. In vivo, the intracerebral administration of miR-124 NPs increased the number of migrating neuroblasts that reached the granule cell layer of the olfactory bulb, both in healthy and in a 6-hydroxydopamine (6-OHDA) mouse model for PD. MiR-124 NPs were also able to induce migration of neurons into the lesioned striatum of 6-OHDA-treated mice. Most importantly, miR-124 NPs proved to ameliorate motor symptoms of 6-OHDA mice, monitored by the apomorphine-induced rotation test. Altogether, we provide clear evidences to support the use of miR-124 NPs as a new therapeutic approach to boost endogenous brain repair mechanisms in a setting of neurodegeneration.

Introduction to microRNAs: Biogenesis, Action, Relevance of Tissue microRNAs in Disease Pathogenesis, Diagnosis and Therapy-The Concept of Circulating microRNAs

MicroRNAs as the endogenous mediators of RNA interference have principal roles in gene expression regulation. Since their discovery in the early 1990s, their number has steadily grown to approximately 2500 known microRNAs at present in humans. MicroRNAs encoded by distinct genes regulate the expression of about 30-60 % of human protein coding genes by targeting their messenger RNAs (mRNAs) and induce mostly posttranscriptional inhibition, or in some cases enhancement. MicroRNAs, as fine regulators of the gene expression, have important roles in development, the physiological functioning of the organism, e.g. organogenesis, immune functioning, vascular system, etc. The deregulation of microRNA expression has been observed in many disorders, such as in carcinogenesis. Given their tissue specificity and stability, and specific disease-related alterations, tissue microRNAs can be exploited as excellent biomarkers in the diagnosis. Moreover, microRNAs might also be envisaged as novel therapeutic targets. Beside tissue microRNAs, novel data show that microRNAs are also present in body fluids that could further extend their diagnostic utility as minimally invasive biomarkers of various diseases, but also raises intriguing questions regarding their biological relevance. In this introductory chapter, we summarise the most relevant features of microRNAs including their biogenesis, action, the biological, pathological, diagnostic and potential therapeutical relevance of tissue microRNAs.

Combined downregulation of microRNA-133a and microRNA-133b predicts chemosensitivity of patients with esophageal squamous cell carcinoma undergoing paclitaxel-based chemotherapy

microRNA-133a (miR-133a) and miR-133b, located on chromosome 18 in the same bicistronic unit, have been commonly identified as being downregulated in esophageal squamous cell carcinoma (ESCC). The aim of this study was to investigate the correlation of miR-133a/b expression with efficacy of paclitaxel-based chemotherapy and clinical outcome of ESCC patients. miR-133a expression and miR-133b expression were examined in 100 newly diagnosed ESCC patients prior to treatment by quantitative real-time PCR. Then, the patients received four cycles of paclitaxel-based chemotherapy, the short-term treatment efficacy was evaluated, and a 3-year follow-up was performed. Expression levels of miR-133a and miR-133b were both significantly lower in ESCC tissues compared to adjacent noncancerous tissues (both P < 0.001). In addition, combined miR-133a/b downregulation was found to be closely correlated with advanced tumor stage (P = 0.02) and poor differentiation (P = 0.01). Moreover, the response rate of ESCC patients to paclitaxel-based chemotherapy was significantly higher in combined miR-133a/b downregulation group compared with other groups (P = 0.02). Furthermore, univariate and multivariate Cox analyses revealed that tumor stage and combined expression of miR-133a/b were independent prognosis factors in ESCC patients. Our data offer the convincing evidence that combined expression of miR-133a and miR-133b may predict chemosensitivity of patients with ESCC undergoing paclitaxel-based chemotherapy, implying its importance in applying 'personalized cancer medicine' in the clinical treatment of ESCC. We also identified combined expression of miR-133a and miR-133b as an effective prognostic marker of this malignancy.

Epigenetic mechanisms underlying the pathogenesis of neurogenetic diseases

There have been considerable advances in uncovering the complex genetic mechanisms that underlie nervous system disease pathogenesis, particularly with the advent of exome and whole genome sequencing techniques. The emerging field of epigenetics is also providing further insights into these mechanisms. Here, we discuss our understanding of the interplay that exists between genetic and epigenetic mechanisms in these disorders, highlighting the nascent field of epigenetic epidemiology-which focuses on analyzing relationships between the epigenome and environmental exposures, development and aging, other health-related phenotypes, and disease states-and next-generation research tools (i.e., those leveraging synthetic and chemical biology and optogenetics) for examining precisely how epigenetic modifications at specific genomic sites affect disease processes.