Development of microRNA therapeutics is coming of age

Role of exosomal small RNA in prostate cancer metastasis

Prostate cancer (PCa) is the second most common cancer in men worldwide. When the disease becomes metastatic, limited treatment strategies exist, and metastatic disease prognoses are difficult to predict. Recently, evidence has emerged, which indicates that small RNAs are detectable in patient fluids, and exosomal small RNA ectopic expression is correlated with the development, progression, and metastasis of human PCa; however, the role of small RNAs in PCa is only partially understood. In this review, we discuss the research status regarding circulating exosomal small RNAs and applications using these small RNAs in PCa particularly looking at metastatic disease. Exosomal small RNAs could be used as potential biomarkers for the early diagnosis, micrometastasis detection, and prognosis of PCa.

Inhibition of miR-449a Promotes Cartilage Regeneration and Prevents Progression of Osteoarthritis in In Vivo Rat Models

Traumatic and degenerative lesions of articular cartilage usually progress to osteoarthritis (OA), a leading cause of disability in humans. MicroRNAs (miRNAs) can regulate the differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) and play important roles in the expression of genes related to OA. However, their functional roles in OA remain poorly understood. Here, we have examined miR-449a, which targets sirtuin 1 (SIRT1) and lymphoid enhancer-binding factor-1 (LEF-1), and observed its effects on damaged cartilage. The levels of chondrogenic markers and miR-449a target genes increased during chondrogenesis in anti-miR-449a-transfected hBMSCs. A locked nucleic acid (LNA)-anti-miR-449a increased cartilage regeneration and expression of type II collagen and aggrecan on the regenerated cartilage surface in acute defect and OA models. Furthermore, intra-articular injection of LNA-anti-miR-449a prevented disease progression in the OA model. Our study indicates that miR-449a may be a novel potential therapeutic target for age-related joint diseases like OA.

Roles of microRNAs in T cell immunity: Implications for strategy development against infectious diseases

T cell immunity plays a vital role in pathogen infections. MicroRNA (miRNAs) are small, single-stranded noncoding RNAs that regulate T cell immunity by targeting key transcriptional factors, signaling proteins, and cytokines associated with T cell activation, differentiation, and function. The dysregulation of miRNA expression in T cells may lead to specific immune responses and can provide new therapeutic opportunities against various infectious diseases. Here, we summarize recent studies that focus on the roles of miRNAs in T cell immunity and highlight miRNA functions in prevalent infectious diseases. Additionally, we also provide insights into the functions of extracellular vesicle miRNAs and attempt to delineate the mechanism of miRNA sorting into extracellular vesicles and their immunomodulatory functions. Moreover, methodologies and strategies for miRNA delivery against infectious diseases are summarized. Finally, potential strategies for miRNA-based therapies are proposed.

The Supercarbonate Apatite-MicroRNA Complex Inhibits Dextran Sodium Sulfate-Induced Colitis

The incidence of inflammatory bowel disease (IBD) is increasing. Nucleic acid-based medicine has potential as a next-generation treatment, but it is rarely successful with IBD. The aim of this study was to establish a microRNA-based therapy in an IBD model. For this purpose, we used microRNA-29 (miR-29) and a supercarbonate apatite (sCA) nanoparticle as a drug delivery system. Injection of sCA-miR-29a-3p or sCA-miR-29b-3p into mouse tail veins markedly prevented and restored inflammation because of dextran sulfate sodium (DSS)-induced colitis. RNA sequencing analysis revealed that miR-29a and miR-29b could inhibit the interferon-associated inflammatory cascade. Subcutaneous injection of sCA-miR-29b also potently inhibited inflammation, and it efficiently targeted CD11c+ dendritic cells (DCs) among various types of immune cells in the inflamed mucosa. RT-PCR analysis indicated that the miR-29 RNAs in CD11c+ DCs suppressed the production of interleukin-6 (IL-6), transforming growth factor β (TGF-β), and IL-23 subunits in DSS-treated mice. This may inhibit Th17 differentiation and subsequent activation, which is critical in IBD pathogenesis. In vivo experiments using a non-natural artificial microRNA sequence revealed that targeting of DCs in the inflamed colon is an exceptional feature of sCA. This study suggests that sCA-miR-29s may open a new avenue in nucleic acid-based medicine for IBD treatment.

Transient postnatal over nutrition induces long-term alterations in cardiac NLRP3-inflammasome pathway

BACKGROUND AND AIMS

The prevalence of obesity is increasing worldwide at an alarming rate. Altered early nutrition, in particular postnatal overfeeding (PNOF), is a risk factor for impaired cardiac function in adulthood. In the understanding of the initiation or progression of heart diseases, NLRP3 inflammasome and non-coding RNAs have been proposed as key players. In this context, the aim of this study was to decipher the role of NLRP3 inflammasome and its post transcriptional control by micro-RNAs in the regulation of cardiac metabolic function induced by PNOF in mice.

METHODS AND RESULTS

Based on a model of mice exposed to PNOF through litter size reduction, we observed increased cardiac protein expression levels of NLRP3 and ETS-1 associated with alterations in insulin signaling. Additionally, miR-193b levels were down-regulated in the adult hearts of overfed animals. In a cardiomyocyte cell line, transfection with miR-193b induced down-regulation of ETS-1 and NLRP3 and improved insulin signaling.

CONCLUSIONS

These findings suggest that the miR-193b could be involved in cardiac phenotypic changes observed in adulthood induced by PNOF likely through the regulation of ETS-1 and NLRP3 expression, and through this of insulin signaling.

MicroRNAs: New Therapeutic Targets for Familial Hypercholesterolemia?

Familial hypercholesterolemia (FH) is the most common inherited form of dyslipidemia and a major cause of premature cardiovascular disease. Management of FH mainly relies on the efficiency of treatments that reduce plasma low-density lipoprotein (LDL) cholesterol (LDL-C) concentrations. MicroRNAs (miRs) have been suggested as emerging regulators of plasma LDL-C concentrations. Notably, there is evidence showing that miRs can regulate the post-transcriptional expression of genes involved in the pathogenesis of FH, including LDLR, APOB, PCSK9, and LDLRAP1. In addition, many miRs are located in genomic loci associated with abnormal levels of circulating lipids and lipoproteins in human plasma. The strong regulatory effects of miRs on the expression of FH-associated genes support of the notion that manipulation of miRs might serve as a potential novel therapeutic approach. The present review describes miRs-targeting FH-associated genes that could be used as potential therapeutic targets in patients with FH or other severe dyslipidemias.

MicroRNA in lung cancer: role, mechanisms, pathways and therapeutic relevance

Lung cancer is the cardinal cause of cancer-related deaths with restricted recourse of therapy throughout the world. Clinical success of therapies is not very promising due to - late diagnosis, limited therapeutic tools, relapse and the development of drug resistance. Recently, small ∼20-24 nucleotides molecules called microRNAs (miRNAs) have come into the limelight as they play outstanding role in the process of tumorigenesis by regulating cell cycle, metastasis, angiogenesis, metabolism and apoptosis. miRNAs essentially regulate gene expression via post-transcriptional regulation of mRNA. Nevertheless, few studies have conceded the role of miRNAs in activation of gene expression. A large body of data generated by numerous studies is suggestive of their tumor-suppressing, oncogenic, diagnostic and prognostic biomarker roles in lung cancer. They have also been implicated in regulating cancer cell metabolism and resistance or sensitivity towards chemotherapy and radiotherapy. Further, miRNAs have also been convoluted in regulation of immune checkpoints - Programmed death 1 (PD-1) and its ligand (PD-L1). These molecules play a significant role in tumor immune escape leading to the generation of a microenvironment favouring tumor growth and progression. Therefore, it is imperative to explore the expression of miRNA and understand its relevance in lung cancer and development of anti-cancer strategies (anti - miRs, miR mimics and micro RNA sponges). In view of the above, the role of miRNA in lung cancer has been dissected and the associated mechanisms and pathways are discussed in this review.

Seed targeting with tiny anti-miR-1297 inhibits EMT in melanoma cells

MicroRNAs (miRNAs) are small, noncoding RNAs that have tissue- and cell-specific expression. They have the ability to regulate the malignant proliferation and transformation of tumour cells. The research focussed on the expression and role of miR-1297 in melanoma. We firstly found that miR-1297 is up-regulated in melanoma tissues and cell lines. Functionally, phosphatase and tension homology deleted on chromsome ten gene (PTEN) was used as a potential target for miR-1297 and detected using Western blotting and immunohistochemistry (IHC). We then used chemical synthesis of anti-miR1297 to explore the influence on melanoma cells and examined the effects on A375 cell proliferation using MTT and western blotting methods. The results showed that anti-miR-1297 transfected A375 cells could inhibit the growth. Furthermore, transfection with anti-miR-1297 reduced PTEN protein expression and partially restrained A375 cells proliferation, migration and reversed Epithelial-Mesenchymal Transition (EMT) progression. In conclusion, we tentatively put forward that miR-1297 might be the key oncomiR in melanoma, and seed-targeted anti-miR-1297 might serve as a new tactic for miR-1297-based therapies.

Targeting cancer stem cells and their niche: perspectives for future therapeutic targets and strategies

A small subpopulation of cells within the bulk of tumors share features with somatic stem cells, in that, they are capable of self-renewal, they differentiate, and are highly resistant to conventional therapy. These cells have been referred to as cancer stem cells (CSCs). Recent reports support the central importance of a cancer stem cell-like niche that appears to help foster the generation and maintenance of CSCs. In response to signals provided by this microenvironment, CSCs express the tumorigenic characteristics that can drive tumor metastasis by the induction of epithelial-mesenchymal-transition (EMT) that in turn fosters the migration and recolonization of the cells as secondary tumors within metastatic niches. We summarize here recent advances in cancer stem cell research including the characterization of their genetic and epigenetic features, metabolic specialities, and crosstalk with aging-associated processes. Potential strategies for targeting CSCs, and their niche, by regulating CSCs plasticity, or therapeutic sensitivity is discussed. Finally, it is hoped that new strategies and related therapeutic approaches as outlined here may help prevent the formation of the metastatic niche, as well as counter tumor progression and metastatic growth.

MicroRNAs in hereditary and sporadic premature aging syndromes and other laminopathies

Hereditary and sporadic laminopathies are caused by mutations in genes encoding lamins, their partners, or the metalloprotease ZMPSTE24/FACE1. Depending on the clinical phenotype, they are classified as tissue‐specific or systemic diseases. The latter mostly manifest with several accelerated aging features, as in Hutchinson–Gilford progeria syndrome (HGPS) and other progeroid syndromes. MicroRNAs are small noncoding RNAs described as powerful regulators of gene expression, mainly by degrading target mRNAs or by inhibiting their translation. In recent years, the role of these small RNAs has become an object of study in laminopathies using in vitro or in vivo murine models as well as cells/tissues of patients. To date, few miRNAs have been reported to exert protective effects in laminopathies, including miR‐9, which prevents progerin accumulation in HGPS neurons. The recent literature has described the potential implication of several other miRNAs in the pathophysiology of laminopathies, mostly by exerting deleterious effects. This review provides an overview of the current knowledge of the functional relevance and molecular insights of miRNAs in laminopathies. Furthermore, we discuss how these discoveries could help to better understand these diseases at the molecular level and could pave the way toward identifying new potential therapeutic targets and strategies based on miRNA modulation.

Carriers for the targeted delivery of aerosolized macromolecules for pulmonary pathologies

INTRODUCTION

Macromolecules with unique effects and potency are increasingly being considered for application in lung pathologies. Numerous delivery strategies for these macromolecules through the lung have been investigated to improve the targeting and overall efficacy.

AREAS COVERED

Targeting approaches from delivery devices, formulation strategies and specific targets are discussed.

EXPERT OPINION

Although macromolecules are a heterogeneous group of molecules, a number of strategies have been investigated at the macro, micro, and nanoscopic scale for the delivery of macromolecules to specific sites and cells of lung tissues. Targeted approaches are already in use at the macroscopic scale through inhalation devices and formulations, but targeting strategies at the micro and nanoscopic scale are still in the laboratory stage. The combination of controlling lung deposition and targeting after deposition, through a combination of targeting strategies could be the future direction for the treatment of lung pathologies through the pulmonary route.

MicroRNAs in the prognosis and therapy of colorectal cancer: From bench to bedside

MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs that can post-transcriptionally regulate the expression of various oncogenes and tumor suppressor genes. Dysregulated expression of many miRNAs have been shown to mediate the signaling pathways critical in the multistep carcinogenesis of colorectal cancer (CRC). MiRNAs are stable and protected from RNase-mediated degradation, thereby enabling its detection in biological fluids and archival tissues for biomarker studies. This review focuses on the role and application of miRNAs in the prognosis and therapy of CRC. While stage II CRC is potentially curable by surgical resection, a significant percentage of stage II CRC patients do develop recurrence. MiRNA biomarkers may be used to stratify such high-risk population for adjuvant chemotherapy to provide better prognoses. Growing evidence also suggests that miRNAs are involved in the metastatic process of CRC. Certain of these miRNAs may thus be used as prognostic biomarkers to identify patients more likely to have micro-metastasis, who could be monitored more closely after surgery and/or given more aggressive adjuvant chemotherapy. Intrinsic and acquired resistance to chemotherapy severely hinders successful chemotherapy in CRC treatment. Predictive miRNA biomarkers for response to chemotherapy may identify patients who will benefit the most from a particular regimen and also spare the patients from unnecessary side effects. Selection of patients to receive the new targeted therapy is becoming possible with the use of predictive miRNA biomarkers. Lastly, forced expression of tumor suppressor miRNA or silencing of oncogenic miRNA in tumors by gene therapy can also be adopted to treat CRC alone or in combination with other chemotherapeutic drugs.

MicroRNA 200b is upregulated in the lungs of fetal rabbits with surgically induced diaphragmatic hernia

OBJECTIVE

Profiling of miR-200b expression and its targets (transforming growth factor [TGF]-β2 and ZEB2) in the surgical rabbit congenital diaphragmatic hernia (DH) model before and after tracheal occlusion (TO).

METHODS

Thirty-eight timed-pregnant rabbits had left DH creation on gestational day (GD) 23. On GD28, 17 randomly selected fetuses had TO. We harvested fetuses at GD23, GD28, or GD30. We calculated lung-to-body weight ratios, processed lungs for miR-200b in situ hybridization and real-time quantitative polymerase chain reaction, and evaluated effects on downstream targets TGF-β2 or ZEB2.

RESULTS

We obtained 16 DH fetuses (n = 7 GD28 and n = 9 GD30), 13 TO fetuses (GD30), and 38 control fetuses (n = 15 GD23, n = 11 GD28, and n = 12 GD30). Diaphragmatic hernia lungs were hypoplastic, and TO resulted in control lung-to-body weight ratio levels. Term miR-200b-3p levels were significantly upregulated in the hypoplastic compared with control ipsilateral lung (1.906 ± 0.90 vs 0.7429 ± 0.44) (P < .01). Fetal TO ipsilateral lungs displayed a variable miR-200b response on in situ hybridization and polymerase chain reaction, with levels similar to control and congenital DH lungs. The TGF-β2 was unchanged in hypoplastic and TO lungs, and ZEB2 tended to be reduced in TO compared with DH lungs (1.79 [0.4-2.9] vs 0.73 [0.5-1.4]).

CONCLUSIONS

Hypoplastic fetal rabbit lungs display upregulation of miR-200b expression although downstream targets are not different from controls. Following TO, fetal rabbit lungs display a variable miR-200b response.

Long-term high altitude hypoxia during gestation suppresses large conductance Ca2+ -activated K+ channel function in uterine arteries: a causal role for microRNA-210

KEY POINTS

Gestational hypoxia represses ten-eleven translocation methylcytosine dioxygenase 1 (TET1) expression in uterine arteries, which is recovered by inhibiting endogenous miR-210. Inhibition of miR-210 rescues BK_Ca channel expression and current in uterine arteries of pregnant animals acclimatized to high altitude hypoxia in a TET-dependent manner. miR-210 blockade restores BK_Ca channel-mediated relaxations and attenuates pressure-dependent myogenic tone in uterine arteries of pregnant animals acclimatized to high altitude.

ABSTRACT

Gestational hypoxia at high altitude has profound adverse effects on the uteroplacental circulation, and is associated with increased incidence of preeclampsia and fetal intrauterine growth restriction. Previous studies demonstrated that suppression of large-conductance Ca²⁺ -activated K⁺ (BK_Ca ) channel function played a critical role in the maladaptation of uteroplacental circulation caused by gestational hypoxia. Yet, the mechanisms underlying gestational hypoxia-induced BK_Ca channel repression remain undetermined. The present study investigated a causal role of microRNA-210 (miR-210) in hypoxia-mediated repression of BK_Ca channel expression and function in uterine arteries using a sheep model. The results revealed that gestational hypoxia significantly decreased ten-eleven translocation methylcytosine dioxygenase 1 (TET1) expression in uterine arteries, which was recovered by inhibiting endogenous miR-210 with miR-210 locked nucleic acid (miR-210-LNA). Of importance, miR-210-LNA restored BK_Ca channel β1 subunit expression in uterine arteries, which was blocked by a competitive TET inhibitor, fumarate, thus functionally linking miR-210 to the TET1-BK_Ca channel cascade. In addition, miR-210-LNA reversed hypoxia-mediated suppression of BK_Ca channel function and rescued the effect of steroid hormones in upregulating BK_Ca channel expression and function in uterine arteries, which were also ablated by fumarate. Collectively, the present study demonstrates a causative effect of miR-210 in the downregulation of TET1 and subsequent repression of BK_Ca channel expression and function, providing a novel mechanistic insight into the regulation of BK_Ca channel function and the molecular basis underlying the maladaptation of uterine vascular function in gestational hypoxia.

MicroRNA-based therapeutics in central nervous system injuries

Central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), are important causes of death and long-term disability worldwide. MicroRNA (miRNA), small non-coding RNA molecules that negatively regulate gene expression, can serve as diagnostic biomarkers and are emerging as novel therapeutic targets for CNS injuries. MiRNA-based therapeutics include miRNA mimics and inhibitors (antagomiRs) to respectively decrease and increase the expression of target genes. In this review, we summarize current miRNA-based therapeutic applications in stroke, TBI and SCI. Administration methods, time windows and dosage for effective delivery of miRNA-based drugs into CNS are discussed. The underlying mechanisms of miRNA-based therapeutics are reviewed including oxidative stress, inflammation, apoptosis, blood-brain barrier protection, angiogenesis and neurogenesis. Pharmacological agents that protect against CNS injuries by targeting specific miRNAs are presented along with the challenges and therapeutic potential of miRNA-based therapies.

Hyperglycaemia-induced epigenetic changes drive persistent cardiac dysfunction via the adaptor p66Shc

AIMS

Hyperglycaemia-induced reactive oxygen species (ROS) are key mediators of cardiac dysfunction. Intensive glycaemic control (IGC) has failed to reduce risk of heart failure in patients with diabetes but the underlying mechanisms remain to be elucidated. The present study investigates whether epigenetic regulation of the pro-oxidant adaptor p66^Shc contributes to persistent myocardial dysfunction despite IGC.

METHODS AND RESULTS

p66^Shc expression was increased in the heart of diabetic mice, and 3-week IGC by slow-release insulin implants did not revert this phenomenon. Sustained p66^Shc upregulation was associated with oxidative stress, myocardial inflammation and left ventricular dysfunction, as assessed by conventional and 2D speckle-tracking echocardiography. In vivo gene silencing of p66^Shc, performed during IGC, inhibited ROS production and restored cardiac function. Furthermore, we show that dysregulation of methyltransferase DNMT3b and deacetylase SIRT1 causes CpG demethylation and histone 3 acetylation on p66^Shc promoter, leading to persistent transcription of the adaptor. Altered DNMT3b/SIRT1 axis in the diabetic heart was explained by upregulation of miR-218 and miR-34a. Indeed, in human cardiomyocytes exposed to high glucose, inhibition of these miRNAs restored the expression of DNMT3b and SIRT1 and erased the adverse epigenetic signatures on p66^Shc promoter. Consistently, reprogramming miR-218 and miR-34a attenuated persistent p66^Shc expression and ROS generation.

CONCLUSIONS

In diabetic left ventricular dysfunction, a complex epigenetic mechanism linking miRNAs and chromatin modifying enzymes drives persistent p66^Shc transcription and ROS generation. Our results set the stage for pharmacological targeting of epigenetic networks to alleviate the clinical burden of diabetic cardiomyopathy.

Controlled Release of RNAi Molecules by Tunable Supramolecular Hydrogel Carriers

Local, sustained release and presentation of RNAi therapeutics can be achieved with hydrogel delivery systems. Here we show the development of a supramolecular hydrogel into a local RNAi delivery system. By careful material design, two simple but effective strategies are introduced to obtain controlled release of two classes of RNAi therapeutics, that is, microRNA and antimiR. It was shown that the release of microRNA could be regulated using cholesterol-modification for interaction with the supramolecular hydrogel. Non-modified antimiR release could be controlled via supramolecular introduction of positively charged additive molecules into the supramolecular hydrogel. In this way, either the cholesterol-modification on the drug or the charge introduction into the hydrogel provides handles for controlled RNAi therapy.

The Emerging Role of microRNAs in Aquaporin Regulation

Aquaporins (AQPs) are membrane channels widely distributed in human tissues. AQPs are essential for water and energy homeostasis being involved in a broad range of pathophysiological processes such as edema, brain injury, glaucoma, nephrogenic diabetes insipidus, salivary and lacrimal gland dysfunction, cancer, obesity and related metabolic complications. Compelling evidence indicates that AQPs are targets for therapeutic intervention with potential broad application. Nevertheless, efficient AQP modulators have been difficult to find due to either lack of selectivity and stability, or associated toxicity that hamper in vivo studies. MicroRNAs (miRNAs) are naturally occurring small non-coding RNAs that regulate post-transcriptional gene expression and are involved in several diseases. Recent identification of miRNAs as endogenous modulators of AQP expression provides an alternative approach to target these proteins and opens new perspectives for therapeutic applications. This mini-review compiles the current knowledge of miRNA interaction with AQPs highlighting miRNA potential for regulation of AQP-based disorders.

miR-1 is increased in pulmonary hypertension and downregulates Kv1.5 channels in rat pulmonary arteries

KEY POINTS

The expression of miR-1 is increased in lungs from the Hyp/Su5416 PAH rat model. Pulmonary artery smooth muscle cells from this animal model are more depolarized and show decreased expression and activity of voltage-dependent potassium channel (Kv)1.5. miR-1 directly targets Kv1.5 channels, reduces Kv1.5 activity and induces membrane depolarization. Antagomir-1 prevents Kv1.5 channel downregulation and the depolarization induced by hypoxia/Su5416 exposition.

ABSTRACT

Impairment of the voltage-dependent potassium channel (Kv) plays a central role in the development of cardiovascular diseases, including pulmonary arterial hypertension (PAH). MicroRNAs are non-coding RNAs that regulate gene expression by binding to the 3'-untranslated region region of specific mRNAs. The present study aimed to analyse the effects of miR-1 on Kv channel function in pulmonary arteries (PA). Kv channel activity was studied in PA from healthy animals transfected with miR-1 or scrambled-miR. Kv currents were studied using the whole-cell configuration of the patch clamp technique. The characterization of the Kv1.5 currents was performed with the selective inhibitor DPO-1. miR-1 expression was increased and Kv1.5 channels were decreased in lungs from a rat model of PAH induced by hypoxia and Su5416. miR-1 transfection increased cell capacitance, reduced Kv1.5 currents and induced membrane depolarization in isolated pulmonary artery smooth muscle cells. A luciferase reporter assay indicated that KCNA5, which encodes Kv1.5 channels, is a direct target gene of miR-1. Incubation of PA with Su5416 and hypoxia (3% O₂ ) increased miR-1 and induced a decline in Kv1.5 currents, which was prevented by antagomiR-1. In conclusion, these data indicate that miR-1 induces pulmonary artery smooth muscle cell hypertrophy and reduces the activity and expression of Kv channels, suggesting a pathophysiological role in PAH.

Aging-Induced Biological Changes and Cardiovascular Diseases

Aging is characterized by functional decline in homeostatic regulation and vital cellular events. This process can be linked with the development of cardiovascular diseases (CVDs). In this review, we discussed aging-induced biological alterations that are associated with CVDs through the following aspects: (i) structural, biochemical, and functional modifications; (ii) autonomic nervous system (ANS) dysregulation; (iii) epigenetic alterations; and (iv) atherosclerosis and stroke development. Aging-mediated structural and biochemical modifications coupled with gradual loss of ANS regulation, vascular stiffening, and deposition of collagen and calcium often disrupt cardiovascular system homeostasis. The structural and biochemical adjustments have been consistently implicated in the progressive increase in mechanical burden and functional breakdown of the heart and vessels. In addition, cardiomyocyte loss in this process often reduces adaptive capacity and cardiovascular function. The accumulation of epigenetic changes also plays important roles in the development of CVDs. In summary, the understanding of the aging-mediated changes remains promising towards effective diagnosis, discovery of new drug targets, and development of new therapies for the treatment of CVDs.

Non-coding RNAs and exercise: pathophysiological role and clinical application in the cardiovascular system

There is overwhelming evidence that regular exercise training is protective against cardiovascular disease (CVD), the main cause of death worldwide. Despite the benefits of exercise, the intricacies of their underlying molecular mechanisms remain largely unknown. Non-coding RNAs (ncRNAs) have been recognized as a major regulatory network governing gene expression in several physiological processes and appeared as pivotal modulators in a myriad of cardiovascular processes under physiological and pathological conditions. However, little is known about ncRNA expression and role in response to exercise. Revealing the molecular components and mechanisms of the link between exercise and health outcomes will catalyse discoveries of new biomarkers and therapeutic targets. Here we review the current understanding of the ncRNA role in exercise-induced adaptations focused on the cardiovascular system and address their potential role in clinical applications for CVD. Finally, considerations and perspectives for future studies will be proposed.

MicroRNAs as potential therapeutics to enhance chemosensitivity in advanced prostate cancer

Docetaxel and cabazitaxel are taxane chemotherapy treatments for metastatic castration-resistant prostate cancer (CRPC). However, therapeutic resistance remains a major issue. MicroRNAs are short non-coding RNAs that can silence multiple genes, regulating several signalling pathways simultaneously. Therefore, synthetic microRNAs may have therapeutic potential in CRPC by regulating genes involved in taxane response and minimise compensatory mechanisms that cause taxane resistance. To identify microRNAs that can improve the efficacy of taxanes in CRPC, we performed a genome-wide screen of 1280 microRNAs in the CRPC cell lines PC3 and DU145 in combination with docetaxel or cabazitaxel treatment. Mimics of miR-217 and miR-181b-5p enhanced apoptosis significantly in PC3 cells in the presence of these taxanes. These mimics downregulated at least a thousand different transcripts, which were enriched for genes with cell proliferation and focal adhesion functions. Individual knockdown of a selection of 46 genes representing these transcripts resulted in toxic or taxane sensitisation effects, indicating that these genes may be mediating the effects of the microRNA mimics. A range of these genes are expressed in CRPC metastases, suggesting that these microRNA mimics may be functional in CRPC. With further development, these microRNA mimics may have therapeutic potential to improve taxane response in CRPC patients.

miR-450b Promotes Osteogenic Differentiation In Vitro and Enhances Bone Formation In Vivo by Targeting BMP3

Osteoporosis is characterized by deterioration of bone microarchitecture and low bone mass. One of the primary causes of osteoporosis is the decrease in the osteogenic differentiation of mesenchymal stem cells (MSCs). Tissue engineering therapy with genetically modified MSCs has attracted much attention in the study of bone regeneration. In this study, we found that the expression level of miR-450b was upregulated during osteogenic differentiation of human adipose-derived mesenchymal stem cells (hADSCs). To explore the effect of miR-450b on the osteogenesis of hADSCs, we performed a series of gain- and loss-of-function analyses and demonstrated that miR-450b not only promoted the process of hADSC differentiation to osteoblasts in vitro but also enhanced ectopic bone formation in vivo. Bone morphogenetic protein 3 (BMP3), the most abundant BMP member in bone, was identified as a direct target of miR-450b. Downregulation of the endogenous expression of BMP3 could mimic the effect of miR-450b upregulation on the osteogenic differentiation of hADSCs. Overall, our study first demonstrated that a novel microRNA miR-450b was essential for hADSC differentiation, which could promote osteogenic differentiation in vitro and enhance bone formation in vivo by directly suppressing BMP3.

Enlightening the Association between Bicuspid Aortic Valve and Aortopathy

Bicuspid aortic valve (BAV) patients have an increased incidence of developing aortic dilation. Despite its importance, the pathogenesis of aortopathy in BAV is still largely undetermined. Nowadays, intense focus falls both on BAV morphology and progression of valvular dysfunction and on the development of aortic dilation. However, less is known about the relationship between aortic valve morphology and aortic dilation. A better understanding of the molecular pathways involved in the homeostasis of the aortic wall, including the extracellular matrix, the plasticity of the vascular smooth cells, TGFβ signaling, and epigenetic dysregulation, is key to enlighten the mechanisms underpinning BAV-aortopathy development and progression. To date, there are two main theories on this subject, i.e., the genetic and the hemodynamic theory, with an ongoing debate over the pathogenesis of BAV-aortopathy. Furthermore, the lack of early detection biomarkers leads to challenges in the management of patients affected by BAV-aortopathy. Here, we critically review the current knowledge on the driving mechanisms of BAV-aortopathy together with the current clinical management and lack of available biomarkers allowing for early detection and better treatment optimization.

Nanotechnology based approaches for detection and delivery of microRNA in healthcare and crop protection

Nanobiotechnology has the potential to revolutionize diverse sectors including medicine, agriculture, food, textile and pharmaceuticals. Disease diagnostics, therapeutics and crop protection strategies are fast emerging using nanomaterials preferably nanobiomaterials. It has potential for development of novel nanobiomolecules which offer several advantages over conventional treatment methods. RNA nanoparticles with many unique features are promising candidates in disease treatment. The miRNAs are involved in many biochemical and developmental pathways and their regulation in plants and animals. These appear to be a powerful tool for controlling various pathological diseases in human, plants and animals, however there are challenges associated with miRNA based nanotechnology. Several advancements made in the field of miRNA therapeutics make it an attractive approach, but a lot more has to be explored in nanotechnology assisted miRNA therapy. The miRNA based technologies can be employed for detection and combating crop diseases as well. Despite these potential advantages, nanobiotechnology applications in the agricultural sector are still in its infancy and have not yet made its mark in comparison with healthcare sector. The review provides a platform to discuss nature, role and use of miRNAs in nanobiotechnology applications.

Context-dependent miR-204 and miR-211 affect the biological properties of amelanotic and melanotic melanoma cells

Despite increasing amounts of experimental evidence depicting the involvement of non-coding RNAs in cancer, the study of BRAFV600E-regulated genes has thus far focused mainly on protein-coding ones. Here, we identify and study the microRNAs that BRAFV600E regulates through the ERK pathway.

By performing small RNA sequencing on A375 melanoma cells and a vemurafenib-resistant clone that was taken as negative control, we discover miR-204 and miR-211 as the miRNAs most induced by vemurafenib. We also demonstrate that, although belonging to the same family, these two miRNAs have distinctive features. miR-204 is under the control of STAT3 and its expression is induced in amelanotic melanoma cells, where it acts as an effector of vemurafenib's anti-motility activity by targeting AP1S2. Conversely, miR-211, a known transcriptional target of MITF, is induced in melanotic melanoma cells, where it targets EDEM1 and consequently impairs the degradation of TYROSINASE (TYR) through the ER-associated degradation (ERAD) pathway. In doing so, miR-211 serves as an effector of vemurafenib's pro-pigmentation activity. We also show that such an increase in pigmentation in turn represents an adaptive response that needs to be overcome using appropriate inhibitors in order to increase the efficacy of vemurafenib.

In summary, we unveil the distinct and context-dependent activities exerted by miR-204 family members in melanoma cells. Our work challenges the widely accepted “same miRNA family = same function” rule and provides a rationale for a novel treatment strategy for melanotic melanomas that is based on the combination of ERK pathway inhibitors with pigmentation inhibitors.

MiR-144-3p promotes the tumor growth and metastasis of papillary thyroid carcinoma by targeting paired box gene 8

Background

Paired box gene 8 (PAX8) is expressed in and indispensable to thyroid development. MiR-144-3p is found dys-regulated in cancers, and it can block the expression of target gens. This study sought to understand the effect of MiR-144-3p in papillary thyroid carcinoma (PTC) as well as the associated mechanisms.

Materials and methods

Real-time PCR, immunohistochemical and Western blot assays were performed to examine the expression of target miRNA and/or genes. CCK-8 and flow cytometry analysis was used to respectively test cell growth, cell cycle progression and apoptosis. Luciferase reporter assay was performed to find out whether miR-144-3p could bind to the 3′ untranslated region of PAX8 or not.

Results

We found that PAX8 decreased in PTC, while miR-144-3p increased in PTC. Over-expression of miR-144-3p promoted the cell viability and cell cycle progression. The expressions of cell-cycle-related genes, cyclin D1, cyclin-dependent kinase 2 and CDC25A were modulated by miR-144-3p. Meanwhile, the presence or absence of miR-144-3p both affected epithelial-mesenchymal transition of PTC by regulating the expression of E-cadherin, N-cadherin and vimentin. Moreover, PAX8 may be a potential direct target of miR-144-3p. Mechanically, the activation of extracellular signal–regulated kinases 1/2, Akt and c-Jun N-terminal kinases may be associated with the tumor-promoting effect of miR-144-3p. In addition, the blockage of miR-144-3p forced the anti-tumor effect delivered by X-ray exposure or paclitaxel.

Conclusion

MiR-144-3p promoted the growth of tumor and the metastasis of PTC by targeting PAX 8. The study provided promising prognosis markers and valuable treatment strategy for PTC.

Local Delivery of miR-21 Stabilizes Fibrous Caps in Vulnerable Atherosclerotic Lesions

miRNAs are potential regulators of carotid artery stenosis and concordant vulnerable atherosclerotic plaques. Hence, we analyzed miRNA expression in laser captured micro-dissected fibrous caps of either ruptured or stable plaques (n = 10 each), discovering that miR-21 was significantly downregulated in unstable lesions. To functionally evaluate miR-21 in plaque vulnerability, miR-21 and miR-21/apolipoprotein-E double-deficient mice (Apoe-/-miR-21-/-) were assessed. miR-21-/- mice lacked sufficient smooth muscle cell proliferation in response to carotid ligation injury. When exposing Apoe-/-miR-21-/- mice to an inducible plaque rupture model, they presented with more atherothrombotic events (93%) compared with miR-21+/+Apoe-/- mice (57%). We discovered that smooth muscle cell fate in experimentally induced advanced lesions is steered via a REST-miR-21-REST feedback signaling pathway. Furthermore, Apoe-/-miR-21-/- mice presented with more pronounced atherosclerotic lesions, greater foam cell formation, and substantially higher levels of arterial macrophage infiltration. Local delivery of a miR-21 mimic using ultrasound-targeted microbubbles into carotid plaques rescued the vulnerable plaque rupture phenotype. In the present study, we identify miR-21 as a key modulator of pathologic processes in advanced atherosclerosis. Targeted, lesion site-specific overexpression of miR-21 can stabilize vulnerable plaques.

miRNA delivery for skin wound healing

The wound healing has remained a worldwide challenge as one of significant public health problems. Pathological scars and chronic wounds caused by injury, aging or diabetes lead to impaired tissue repair and regeneration. Due to the unique biological wound environment, the wound healing is a highly complicated process, efficient and targeted treatments are still lacking. Hence, research-driven to discover more efficient therapeutics is a highly urgent demand. Recently, the research results have revealed that microRNA (miRNA) is a promising tool in therapeutic and diagnostic fields because miRNA is an essential regulator in cellular physiology and pathology. Therefore, new technologies for wound healing based on miRNA have been developed and miRNA delivery has become a significant research topic in the field of gene delivery.

Delivery systems of current biologicals for the treatment of chronic cutaneous wounds and severe burns

While wound therapy remains a clinical challenge in current medical practice, much effort has focused on developing biological therapeutic approaches. This paper presents a comprehensive review of delivery systems for current biologicals for the treatment of chronic wounds and severe burns. The biologicals discussed here include proteins such as growth factors and gene modifying molecules, which may be delivered to wounds free, encapsulated, or released from living systems (cells, skin grafts or skin equivalents) or biomaterials. Advances in biomaterial science and technologies have enabled the synthesis of delivery systems such as scaffolds, hydrogels and nanoparticles, designed to not only allow spatially and temporally controlled release of biologicals, but to also emulate the natural extracellular matrix microenvironment. These technologies represent an attractive field for regenerative wound therapy, by offering more personalised and effective treatments.

Molecular mechanism of diabetic cardiomyopathy and modulation of microRNA function by synthetic oligonucleotides

Diabetic cardiomyopathy (DCM) is a chronic complication in individuals with diabetes and is characterized by ventricular dilation and hypertrophy, diastolic dysfunction, decreased or preserved systolic function and reduced ejection fraction eventually resulting in heart failure. Despite being well characterized, the fundamental mechanisms leading to DCM are still elusive. Recent studies identified the involvement of small non-coding small RNA molecules such as microRNAs (miRs) playing a key role in the etiology of DCM. Therefore, miRs associated with DCM represents a new class of targets for the development of mechanistic therapeutics, which may yield marked benefits compared to other therapeutic approaches. Indeed, few miRs currently under active clinical investigation, with many expressing cautious optimism that miRs based therapies will succeed in the coming years. The major caution in using miRs based therapy is the need to improve the stability and specificity following systemic injection, which can be achieved through chemical and structural modification. In this review, we first discuss the established role of miRs in DCM and the advances in miRs based therapeutic strategies for the prevention/treatment of DCM. We next discuss the currently employed chemical modification of miR oligonucleotides and their utility in therapies specifically focusing on the DCM. Finally, we summarize the commonly used delivery system and approaches for assessment of miRNA modulation and potential off-target effects.

Experimental Demyelination and Axonal Loss Are Reduced in MicroRNA-146a Deficient Mice

Background

The cuprizone (CPZ) model of multiple sclerosis (MS) was used to identify microRNAs (miRNAs) related to in vivo de- and remyelination. We further investigated the role of miR-146a in miR-146a-deficient (KO) mice: this miRNA is differentially expressed in MS lesions and promotes differentiation of oligodendrocyte precursor cells (OPCs) during remyelination, but its role has not been examined during demyelination.

Methods

MicroRNAs were examined by Agilent Mouse miRNA Microarray in the corpus callosum during CPZ-induced demyelination and remyelination. Demyelination, axonal loss, changes in number of oligodendrocytes, OPCs, and macrophages/microglia was compared by histology/immunohistochemistry between KO and WT mice. Differential expression of target genes and proteins of miR-146a was analyzed in the transcriptome (4 × 44K Agilent Whole Mouse Genome Microarray) and proteome (liquid chromatography tandem mass spectrometry) of CPZ-induced de- and remyelination in WT mice. Levels of proinflammatory molecules in the corpus callosum were compared in WT versus KO mice by Meso Scale Discovery multiplex protein analysis.

Results

miR-146a was increasingly upregulated during CPZ-induced de- and remyelination. The absence of miR-146a in KO mice protected against demyelination, axonal loss, body weight loss, and atrophy of thymus and spleen. The number of CNP⁺ oligodendrocytes was increased during demyelination in the miR-146a KO mice, while there was a trend of increased number of NG2⁺ OPCs in the WT mice. miR-146a target genes, SNAP25 and SMAD4, were downregulated in the proteome of demyelinating corpus callosum in WT mice. Higher levels of SNAP25 were measured by ELISA in the corpus callosum of miR-146a KO mice, but there was no difference between KO and WT mice during demyelination. Multiplex protein analysis of the corpus callosum lysate revealed upregulated TNF-RI, TNF-RII, and CCL2 in the WT mice in contrast to KO mice. The number of Mac3⁺ and Iba1⁺ macrophages/microglia was reduced in the demyelinating corpus callosum of the KO mice.

Conclusion

During demyelination, absence of miR-146a reduced inflammatory responses, demyelination, axonal loss, the number of infiltrating macrophages, and increased the number of myelinating oligodendrocytes. The number of OPCs was slightly higher in the WT mice during remyelination, indicating a complex role of miR-146a during in vivo de- and remyelination.

Clinical and Molecular Aspects of Cardiomyopathies: Emerging Therapies and Clinical Trials

Cardiomyopathies are diseases of the myocardium, often genetically determined, associated with heterogeneous phenotypes and clinical manifestations. Despite significant progress in the understanding of these conditions, available treatments mostly target late complications, whereas approaches that promise to interfere with the primary mechanisms and natural history are just beginning to surface. The last decade has witnessed the establishment of large international cardiomyopathy registries, paralleled by advances in cardiac imaging and genetic testing, deeper understanding of the pathophysiology and growing involvement by the pharmaceutical industry. As a result, the number of molecular interventions under scrutiny is increasing sharply.

Targeted delivery of anti-miR-155 by functionalized mesoporous silica nanoparticles for colorectal cancer therapy

INTRODUCTION

MicroRNA-155 (miR-155) is an oncogenic microRNA, which is upregulated in many human cancers including colorectal cancer (CRC). Overexpression of miR-155 has been found to regulate several cancer-related pathways, and therefore, targeting miR-155 may be an effective strategy for cancer therapy. However, effective and safe delivery of anti-miR-155 to tumors remains challenging for the clinical applications of anti-miR-155-based therapeutics.

METHODS

In this study, we explored the expression of miR-155 and the transcription factor nuclear factor kappa B (NF-κB) in CRC tissues and cell lines, and the possible relationship between miR-155 and NF-κB. We further report on anti-miR-155-loaded mesoporous silica nanoparticles (MSNs) modified with polymerized dopamine (PDA) and AS1411 aptamer (MSNs-anti-miR-155@PDA-Apt) for the targeted treatment of CRC.

RESULTS

Results showed that miR-155 is overexpressed in CRC tissues and cell lines, and there is a positive feedback loop between NF-κB and miR-155. Compared to the control groups, MSNs-anti-miR-155@PDA-Apt could efficiently downregulate miR-155 expression in SW480 cells and achieve significantly high targeting efficiency and enhanced therapeutic effects in both in vivo and in vitro experiments. Furthermore, inhibition of miR-155 by MSNs-anti-miR-155@PDA-Apt can enhance the sensitivity of SW480 to 5-fluorouracil chemotherapy.

CONCLUSION

Thus, our results suggested that MSNs-anti-miR-155@PDA-Apt is a promising nanoformulation for CRC treatment.

Adeno-Associated Virus Serotype 2 Vector-Mediated Reintroduction of microRNA-19b Attenuates Hepatic Fibrosis

Fibrotic liver injury is a significant healthcare burden in the United States. It represents a major cause of morbidity and mortality for which there are no effective Food and Drug Administration-approved treatment strategies. Fibrosis is considered a disruption of the normal wound healing responses mediated by fibroblastic cells, which are triggered and sustained by pro-fibrotic cytokines such as transforming growth factor beta 1 (TGF-β1). TGF-β1-mediated trans-differentiation of hepatic stellate cells (HSCs) from quiescent to activated myofibroblasts is a pivotal event in the development of fibrosis. Activation is accompanied by global changes in microRNA (miR) expression. It has been previously reported that miR19b is decreased in activated HSCs and contributes to increased expression of TGF-β receptor II and connective tissue growth factor, both confirmed targets of miR19b. An adeno-associated virus serotype 2 vector (AAV2) with a miR19b transgene downstream of enhanced green fluorescent protein under the murine collage alpha 1(I) promoter was developed specifically to target HSCs. Male Sprague Dawley rats (250 g) underwent sham or bile-duct ligation (BDL) surgery. Directly after BDL, rats received AAV2-miR19b, AAV2-control, or vehicle normal saline (NS) by portal-vein injection. After 2 weeks, the animals were euthanized, and blood was collected for alanine and aspartate aminotransferase, total and direct bilirubin, and alkaline phosphatase. Tissue was collected for RNA and protein extraction and histology. Fibrosis and measures of hepatic injury were significantly reduced in AAV2-miR19b-treated rats in combination with significant improvements in total and direct bilirubin. Histological analysis of collagen by PicroSirius Red staining revealed a ∼50% reduction compared to AAV2-control or NS-injected animals. Pro-fibrotic markers, smooth-muscle alpha-actin, TGF-β receptor II, and collagen alpha 2(I) mRNA and protein were significantly decreased compared to AAV2-control and NS groups. AAV2-mediated reintroduction of miR-19b, specifically expressed in HSCs, improved liver function, inhibited fibrosis, and improved measures of hepatic injury in a BDL model.

Noncoding RNAs in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the main cause of dementia among the elderly worldwide. Despite intense efforts to develop drugs for preventing and treating AD, no effective therapies are available as yet, posing a growing burden at the personal, medical, and socioeconomic levels. AD is characterized by the production and aggregation of amyloid β (Aβ) peptides derived from amyloid precursor protein (APP), the presence of hyperphosphorylated microtubule-associated protein Tau (MAPT), and chronic inflammation leading to neuronal loss. Aβ accumulation and hyperphosphorylated Tau are responsible for the main histopathological features of AD, Aβ plaques, and neurofibrillary tangles (NFTs), respectively. However, the full spectrum of molecular factors that contribute to AD pathogenesis is not known. Noncoding (nc)RNAs, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), regulate gene expression at the transcriptional and posttranscriptional levels in various diseases, serving as biomarkers and potential therapeutic targets. There is rising recognition that ncRNAs have been implicated in both the onset and pathogenesis of AD. Here, we review the ncRNAs implicated posttranscriptionally in the main AD pathways and discuss the growing interest in targeting regulatory ncRNAs therapeutically to combat AD pathology. WIREs RNA 2018, 9:e1463. doi: 10.1002/wrna.1463 This article is categorized under: RNA in Disease and Development > RNA in Disease.

Identification of associations between small molecule drugs and miRNAs based on functional similarity

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that regulate gene expression at post-transcriptional level. Increasing evidences show aberrant expression of miRNAs in varieties of diseases. Targeting the dysregulated miRNAs with small molecule drugs has become a novel therapy for many human diseases, especially cancer. Here, we proposed a novel computational approach to identify associations between small molecules and miRNAs based on functional similarity of differentially expressed genes. At the significance level of p < 0.01, we constructed the small molecule and miRNA functional similarity network involving 111 small molecules and 20 miRNAs. Moreover, we also predicted associations between drugs and diseases through integrating our identified small molecule-miRNA associations with experimentally validated disease related miRNAs. As a result, we identified 2265 associations between FDA approved drugs and diseases, in which ~35% associations have been validated by comprehensive literature reviews. For breast cancer, we identified 19 potential drugs, in which 12 drugs were supported by previous studies. In addition, we performed survival analysis for the patients from TCGA and GEO database, which indicated that the associated miRNAs of 4 drugs might be good prognosis markers in breast cancer. Collectively, this study proposed a novel approach to predict small molecule and miRNA associations based on functional similarity, which may pave a new way for miRNA-targeted therapy and drug repositioning.

A novel microRNA identified in hepatocellular carcinomas is responsive to LEF1 and facilitates proliferation and epithelial-mesenchymal transition via targeting of NFIX

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers. It has been demonstrated that various cellular microRNAs (miRNAs) play an important role in HCC development. Here, we analyzed the miRNA profile in HCC tissues by Solexa sequencing, and we identified a novel microRNA, miR-HCC1, which is upregulated in HCC tissues. Further experiments showed that miR-HCC1 promoted HCC cell proliferation in vivo and in vitro, and migration and invasion resulting from the epithelial-mesenchymal transition (EMT) process. Nuclear factor I/X (NFIX), which inhibited cell proliferation, migration and invasion in HCC cells, was identified as a direct and functional target of miR-HCC1. Furthermore, lymphoid enhancer binding factor 1 (LEF1), a transcription factor, was shown to bind the promoter of miR-HCC1 and activate its expression. Collectively, these results indicate that LEF1-upregulated miR-HCC1 functions as an oncogene through the negative regulation of NFIX expression, which links the LEF1/miR-HCC1/NFIX axis to contribute to cell proliferation, migration and invasion of HCC cells and could provide novel insights into miRNA function and hepatocarcinogenesis and potential biomarkers for HCC.

The "melanoma-enriched" microRNA miR-4731-5p acts as a tumour suppressor

We previously identified miR-4731-5p (miR-4731) as a melanoma-enriched microRNA following comparison of melanoma with other cell lines from solid malignancies. Additionally, miR-4731 has been found in serum from melanoma patients and expressed less abundantly in metastatic melanoma tissues from stage IV patients relative to stage III patients. As miR-4731 has no known function, we used biotin-labelled miRNA duplex pull-down to identify binding targets of miR-4731 in three melanoma cell lines (HT144, MM96L and MM253). Using the miRanda miRNA binding algorithm, all pulled-down transcripts common to the three cell lines (n=1092) had potential to be targets of miR-4731 and gene-set enrichment analysis of these (via STRING v9.1) highlighted significantly associated genes related to the 'cell cycle' pathway and the 'melanosome'. Following miR-4731 overexpression, a selection (n=81) of pull-down transcripts underwent validation using a custom qRT-PCR array. These data revealed that miR-4731 regulates multiple genes associated with the cell cycle (e.g. CCNA2, ORC5L, and PCNA) and the melanosome (e.g. RAB7A, CTSD, and GNA13). Furthermore, members of the synovial sarcoma X breakpoint family (SSX) (melanoma growth promoters) were also down-regulated (e.g. SSX2, SSX4, and SSX4B) as a result of miR-4731 overexpression. Moreover, this down-regulation of mRNA expression resulted in ablation or reduction of SSX4 protein, which, in keeping with previous studies, resulted in loss of 2D colony formation. We therefore speculate that loss of miR-4731 expression in stage IV patient tumours supports melanoma growth by, in part; reducing its regulatory control of SSX expression levels.

Elevated CXCL1 increases hepatocellular carcinoma aggressiveness and is inhibited by miRNA-200a

In this study, we investigated the value of measurement of the chemokine CXCL1 in clinical management of hepatocellular carcinoma (HCC) and its possible role in the molecular pathogenesis of HCC. High CXCL1 expression predicted recurrence in HCC patients and promoted tumor progression in both in vivo and in vitro experimental systems. Overexpression of CXCL1 increased mitochondrial metabolism and activated the epithelial-to-mesenchymal transition (EMT). Using computational analysis we identified the microRNA miR-200a as a putative post-transcriptional regulator of CXCL1. We found that levels of miR-200a were inversely correlated with CXCL1 expression in HCC patient tissue samples by northern blot and qRT-PCR. Furthermore, CXCL1 was identified as a direct target which was bound and inhibited by miR- 200a. These findings provide new insights into the role of CXCL1 in HCC and its post-transcriptional regulation and suggest it may be a prognostic indicator for poor outcomes and a potential target for therapy.

Mutant p53 cancers reprogram macrophages to tumor supporting macrophages via exosomal miR-1246

TP53 mutants (mutp53) are involved in the pathogenesis of most human cancers. Specific mutp53 proteins gain oncogenic functions (GOFs) distinct from the tumor suppressor activity of the wild-type protein. Tumor-associated macrophages (TAMs), a hallmark of solid tumors, are typically correlated with poor prognosis. Here, we report a non-cell-autonomous mechanism, whereby human mutp53 cancer cells reprogram macrophages to a tumor supportive and anti-inflammatory state. The colon cancer cells harboring GOF mutp53 selectively shed miR-1246-enriched exosomes. Uptake of these exosomes by neighboring macrophages triggers their miR-1246-dependent reprogramming into a cancer-promoting state. Mutp53-reprogammed TAMs favor anti-inflammatory immunosuppression with increased activity of TGF-β. These findings, associated with poor survival in colon cancer patients, strongly support a microenvironmental GOF role for mutp53 in actively engaging the immune system to promote cancer progression and metastasis.

p53 gain of function mutants (mutp53) are involved in the pathogenesis of most human cancers. Here, the authors show that mutp53 regulates the tumor microenvironment by inducing the release of specific exosomes containing miR-1246 that once received by macrophages turns them into tumor supportive macrophages.

Nuclear functions of mammalian MicroRNAs in gene regulation, immunity and cancer

MicroRNAs (miRNAs) are endogenous non-coding RNAs that contain approximately 22 nucleotides. They serve as key regulators in various biological processes and their dysregulation is implicated in many diseases including cancer and autoimmune disorders. It has been well established that the maturation of miRNAs occurs in the cytoplasm and miRNAs exert post-transcriptional gene silencing (PTGS) via RNA-induced silencing complex (RISC) pathway in the cytoplasm. However, numerous studies reaffirm the existence of mature miRNA in the nucleus, and nucleus-cytoplasm transport mechanism has also been illustrated. Moreover, active regulatory functions of nuclear miRNAs were found including PTGS, transcriptional gene silencing (TGS), and transcriptional gene activation (TGA), in which miRNAs bind nascent RNA transcripts, gene promoter regions or enhancer regions and exert further effects via epigenetic pathways. Based on existing interaction rules, some miRNA binding sites prediction software tools are developed, which are evaluated in this article. In addition, we attempt to explore and review the nuclear functions of miRNA in immunity, tumorigenesis and invasiveness of tumor. As a non-canonical aspect of miRNA action, nuclear miRNAs supplement miRNA regulatory networks and could be applied in miRNA based therapies.

Targeted delivery of miRNA-204-5p by PEGylated polymer nanoparticles for colon cancer therapy

AIM

miRNAs have been recognized for their potential in cancer therapeutics, and multiple miRNAs were suggested to affect target genes expression. To overcome limitations of free synthetic miRNAs, such as easily degraded in biofluids and limited in cellular uptake, novel miRNAs delivery systems need to be developed.

MATERIALS & METHODS

Using surface-functionalizing technique, poly(D,L-lactide-co-glycolide)/poly(L-lactide)-block-poly(ethylene glycol)-folate polymer nanoparticle (PLGA/PLA-PEG-FA) loaded with miR-204-5p (FA-NPs-miR-204) was developed. The therapeutic efficacy of FA-NPs-miR-204 was evaluated in the Luc-HT-29 xenograft tumor model in vivo.

RESULTS

FA-NPs-miR-204 could be taken up by HT-29  and HCT-116 cells efficiently, resulting in significant inhibitory effect on cell proliferation and promotive effect on cell apoptosis. In vivo study showed that FA-NPs-miR-204 could exert tumor suppressive function in Luc-HT-29 xenograft model.

CONCLUSION

Our study demonstrates a convenient miRNA delivery system that targets tumor tissue and exerts tumor suppressive function, thus demonstrating a potential new therapeutic option for colon cancer.

MicroRNAs-103/107 Regulate Autophagy in the Epidermis

We have shown that microRNAs-103 and -107 (miRs-103/107) positively regulate end-stage autophagy by ensuring dynamin activity in cultured keratinocytes. Most work in end-stage autophagy has been conducted using in vitro model systems. In vivo regulation of end-stage autophagy in epidermis remains unknown. Here, we used antagomirs to subcutaneously knock down miR-107 in the skin; conversely, we delivered miR-107 mimic subcutaneously via in vivo transfection to increase this miR. We found that antagomir-107 treatment in epidermis: (i) depleted endogenous miR-107; (ii) increased GFP-LC3 puncta in epidermal basal layers of GFP-LC3 transgenic mice, indicative of an accumulation of autophagosomes; (iii) inhibited LC3 turnover and increased p62, suggesting an inhibition of autophagy flux; and (iv) increased phosphorylated dynamin (p-dynamin, an inactive form), a key enzyme in end-stage autophagy. Conversely, miR-107 mimic treatment in mouse epidermis: decreased GFP-LC3 puncta in basal layer, as well as p62 protein levels; and diminished p-dynamin, indicative of activation of this enzyme. In human epidermal keratinocytes, antagos-103/107 cause the formation of large vacuoles and an increase in p-dynamin, which can be rescued by inhibition of protein kinase C pathway. Collectively, these results suggest that the miR-103/107 family has a critical role in regulating end-stage autophagy in mouse epidermis via PLD1/2-protein kinase C-dynamin pathway.

MicroRNA-34a regulates doxorubicin-induced cardiotoxicity in rat

New strategies to prevent and early detect the cardiotoxic effects of the anticancer drug doxorubicin (DOXO) are required. MicroRNAs emerged as potential diagnostic, therapeutic and prognostic approaches in cardiovascular diseases. MiR-34a has a role in cardiac dysfunction and ageing and is involved in several cellular processes associated with DOXO cardiotoxicity. Our in vitro and in vivo results indicated that after DOXO exposure the levels of miR-34a are enhanced in cardiac cells, including Cardiac Progenitor Cells (CPCs). Since one of the determining event responsible for the initiation and evolution of the DOXO toxicity arises at the level of the CPC compartment, we evaluated if miR-34a pharmacological inhibition in these cells ameliorates the detrimental aftermath of the drug. AntimiR-34a has beneficial consequences on vitality, proliferation, apoptosis and senescence of DOXO-treated rat CPC. These effects are mediated by an increase of prosurvival miR-34a targets Bcl-2 and SIRT1, accompanied by a decrease of acetylated-p53 and p16^INK4a. Importantly, miR-34a silencing also reduces the release of this miRNA from DOXO-exposed rCPCs, decreasing its negative paracrine effects on other rat cardiac cells. In conclusion, the silencing of miR-34a could represent a future therapeutic option for cardioprotection in DOXO toxicity and at the same time, it could be considered as a circulating biomarker for anthracycline-induced cardiac damage.