microRNAs: small molecules with big roles - C. elegans to human cancer

The role of miR-765 in human cancers

MicroRNAs, a collection of short noncoding RNAs, are promising biomarkers for identifying cancer in its early stages and tracking the effectiveness of treatment. This is due to their critical role in regulating gene expression and other vital biological functions via cell-level epigenetic mechanisms. This review brings together data on the molecular and clinical effects of miR-765 on different types of cancer. Significant variation in miR-765 levels has been observed in a variety of cancer types, suggesting that it could have an oncogene or tumor suppressor role. A number of pathways, including PLP2/Notch, VEGFA/Akt1, PDX1, KLK4, RUNX2, DPF3, EMP3, APE1, ERK/EMT axis, and others, are impacted by the inclusion of miR-765 in their analysis. MiR-765 is an essential biomarker that shows promise as a diagnostic tool for various types of cancer. The latest research has identified them as reliable predictive markers for detecting tumor development at an early stage. Based on our study, miR-765 shows promising potential as a biomarker for prognosis in multiple types of cancer. Specifically, we suggest that miR-765 could be an early detection marker for tumor development, progression, and metastasis.

An expandable FLP-ON::TIR1 system for precise spatiotemporal protein degradation in Caenorhabditis elegans

The auxin-inducible degradation system has been widely adopted in the Caenorhabditis elegans research community for its ability to empirically control the spatiotemporal expression of target proteins. This system can efficiently degrade auxin-inducible degron (AID)-tagged proteins via the expression of a ligand-activatable AtTIR1 protein derived from A. thaliana that adapts target proteins to the endogenous C. elegans proteasome. While broad expression of AtTIR1 using strong, ubiquitous promoters can lead to rapid degradation of AID-tagged proteins, cell type-specific expression of AtTIR1 using spatially restricted promoters often results in less efficient target protein degradation. To circumvent this limitation, we have developed an FLP/FRT3-based system that functions to reanimate a dormant, high-powered promoter that can drive sufficient AtTIR1 expression in a cell type-specific manner. We benchmark the utility of this system by generating a number of tissue-specific FLP-ON::TIR1 drivers to reveal genetically separable cell type-specific phenotypes for several target proteins. We also demonstrate that the FLP-ON::TIR1 system is compatible with enhanced degron epitopes. Finally, we provide an expandable toolkit utilizing the basic FLP-ON::TIR1 system that can be adapted to drive optimized AtTIR1 expression in any tissue or cell type of interest.

miRNA in Parkinson's disease: From pathogenesis to theranostic approaches

Parkinson's disease (PD) is an age associated neurological disorder which is specified by cardinal motor symptoms such as tremor, stiffness, bradykinesia, postural instability, and non-motor symptoms. Dopaminergic neurons degradation in substantia nigra region and aggregation of αSyn are the classic signs of molecular defects noticed in PD pathogenesis. The discovery of microRNAs (miRNA) predicted to have a pivotal part in various processes regarding regularizing the cellular functions. Studies on dysregulation of miRNA in PD pathogenesis has recently gained the concern where our review unravels the role of miRNA expression in PD and its necessity in clinical validation for therapeutic development in PD. Here, we discussed how miRNA associated with ageing process in PD through molecular mechanistic approach of miRNAs on sirtuins, tumor necrosis factor-alpha and interleukin-6, dopamine loss, oxidative stress and autophagic dysregulation. Further we have also conferred the expression of miRNAs affected by SNCA gene expression, neuronal differentiation and its therapeutic potential with PD. In conclusion, we suggest more rigorous studies should be conducted on understanding the mechanisms and functions of miRNA in PD which will eventually lead to discovery of novel and promising therapeutics for PD.

MicroRNAs as a Novel Player for Differentiation of Mesenchymal Stem Cells into Cardiomyocytes

Cardiovascular disease (CVD) is defined as a class of disorders affecting the heart and blood vessels. Cardiomyocytes and endothelial cells play important roles in cardiac regeneration and heart repair. However, the proliferating capacity of cardiomyocytes is limited. To overcome this issue, mesenchymal stem cells (MSCs) have emerged as an alternative strategy for CVD therapy. MSCs can proliferate and differentiate (or trans-differentiate) into cardiomyocytes. Several in vitro and in vivo differentiation protocols have been used to obtain MSCs-derived cardiomyocytes. It was recently investigated that microRNAs (miRNAs) by targeting several signaling pathways, including STAT3, Wnt/β-catenin, Notch, and TBX5, play a crucial role in regulating cardiomyocytes' differentiation of MSCs. In this review, we focused on the role of miRNAs in the differentiation of MSCs into cardiomyocytes.

MicroRNAs influence and longevity

Background

MiRNAs play critical roles in the regulation of cellular function, life span, and the aging process. They can affect longevity positively and negatively through different aging pathways.

Main text

MiRNAs are a group of short non-coding RNAs that regulate gene expressions at post-transcriptional levels. The different types of alterations in miRNAs biogenesis, mRNA expressions, and activities of miRNA-protein complexes can affect the regulation of normal post-transcriptional gene process, which may lead to aging, age-related diseases, and an earlier death. It seems that the influence of deregulation of miRNAs on senescence and age-related diseases occurring by targeting aging molecular pathways can be used for diagnosis and prognosis of them. Therefore, the expression and function of miRNAs should be studied more accurately with new applicable and validated experimental tools. However, the current review wishes to highlight simply a connection among miRNAs, senescence and some age-related diseases.

Conclusion

Despite several research indicating the key roles of miRNAs in aging and longevity, further investigations are still needed to elucidate the essential roles of miRNAs in controlling mRNA regulation, cell proliferation, death and/or protection during stress and health problems. Besides, more research on miRNAs will help to identify new targets for alternative strategies regarding effectively screen, treat, and prevent diseases as well as make slow the aging process.

Roles and action mechanisms of bile acid-induced gastric intestinal metaplasia: a review

Gastric intestinal metaplasia (IM) is a precancerous lesion that increases the risk of subsequent gastric cancer (GC) development. Therefore, the mechanism of IM has been the focus of basic and clinical research. Helicobacter pylori (H. pylori) infection has been recognized as the main pathogenesis of gastric IM. However, more and more studies have shown that chronic inflammation of gastric mucosa caused by bile reflux is the key pathogenic factor of gastric IM. Bile reflux activates the expression of IM biomarkers via the bile acid receptor. In addition, microRNAs, exosomes, and epigenetics are also involved in the occurrence and development of bile acid-induced gastric IM. Currently, the relevant research is still very few. The molecular mechanism of the phenotypic transformation of gastrointestinal epithelial cells induced by bile acids has not been fully understood. This article mainly reviews the physiology and pathology of bile acid, mechanism of gastric IM induced by bile acid, bile acid receptors, and so on, in order to provide reference for further research.

A review on interplay between small RNAs and oxidative stress in cancer progression

Oxidative stress has been known to be the underlying cause in many instances of cancer development. The new aspect of cancer genesis that has caught the attention of many researchers worldwide is its connection to non-coding RNAs (ncRNAs). ncRNAs may not be protein coding, but in light of the more recent discovery of their wide range of functions, the term 'dark matter of the genome' has been rendered inapplicable. There is an extensive mention of colon cancer as an example, where some of these ncRNAs and their manipulations have seen significant progress. As of now, the focus is on discovering a non-invasive, cost-effective method for diagnosis that is easier to monitor and can be conducted before visible symptoms indicate cancer in a patient, by which time it may already be too late. The concept of liquid biopsies has revolutionized recent diagnostic measures. It has been possible to detect circulating parts of the cancer genome or other biomarkers in the patients' bodily fluids, resulting in the effective management of the disease. This has led these ncRNAs to be considered effective therapeutic targets and extrinsic modifications in several tumor types, proven to be effective as therapy. However, there is a vast scope for further understanding and pertinent application of our acquired knowledge and expanding it in enhancing the utilization of ncRNAs for a better prognosis, quicker diagnosis, and improved management of cancer. This review explores the prognosis of cancer and related mutations by scrutinizing small ncRNAs in the disease.

Alcohol induced impairment/abnormalities in brain: Role of MicroRNAs

Alcohol is a highly toxic substance and has teratogenic properties that can lead to a wide range of developmental disorders. Excessive use of alcohol can change the structural and functional aspects of developed brain and other organs. Which can further lead to significant health, social and economic implications in many countries of the world. Convincing evidence support the involvement of microRNAs (miRNAs) as important post-transcriptional regulators of gene expression in neurodevelopment and maintenance. They also show differential expression following an injury. MiRNAs are the special class of small non coding RNAs that can modify the gene by targeting the mRNA and fine tune the development of cells to organs. Numerous pieces of evidences have shown the relationship between miRNA, alcohol and brain damage. These studies also show how miRNA controls different cellular mechanisms involved in the development of alcohol use disorder. With the increasing number of research studies, the roles of miRNAs following alcohol-induced injury could help researchers to recognize alternative therapeutic methods to treat/cure alcohol-induced brain damage. The present review summarizes the available data and brings together the important miRNAs, that play a crucial role in alcohol-induced brain damage, which will help in better understanding complex mechanisms. Identifying these miRNAs will not only expand the current knowledge but can lead to the identification of better targets for the development of novel therapeutic interventions.

Sulforaphane as a Promising Natural Molecule for Cancer Prevention and Treatment

Tumorigenicity-inhibiting compounds have been identified in our daily diet. For example, isothiocyanates (ITCs) found in cruciferous vegetables were reported to have potent cancer-prevention activities. The best characterized ITC is sulforaphane (SF). SF can simultaneously modulate multiple cellular targets involved in carcinogenesis, including (1) modulating carcinogen-metabolizing enzymes and blocking the action of mutagens; (2) inhibition of cell proliferation and induction of apoptosis; and (3) inhibition of neo-angiogenesis and metastasis. SF targets cancer stem cells through modulation of nuclear factor kappa B (NF-κB), Sonic hedgehog (SHH), epithelial-mesenchymal transition, and Wnt/β-catenin pathways. Conventional chemotherapy/SF combination was tested in several studies and resulted in favorable outcomes. With its favorable toxicological profile, SF is a promising agent in cancer prevention and/or therapy. In this article, we discuss the human metabolism of SF and its effects on cancer prevention, treatment, and targeting cancer stem cells, as well as providing a brief review of recent human clinical trials on SF.

Mucosal microRNAs relate to age and severity of disease in ulcerative colitis

Despite significant evidence that the expression of several microRNAs (miRNAs) impacts disease activity in patients with ulcerative colitis (UC), it remains unknown if the more severe disease phenotype seen in pediatric onset UC can be explained by an altered miRNA expression. In this study, we assessed the relationship between miRNA expression, age, and disease severity in pediatric and adult patients with UC. Using RT-qPCR, we analyzed the expression of miR-21, miR-31, miR-126, miR-142 and miR-155 in paraffin embedded rectum biopsies from 30 pediatric and 30 adult-onset UC patients. We found that lesions from adult patients had significantly higher expression levels of miR-21 compared to pediatric patients and that the expression levels of miR-31 (all patients) and miR-155 (pediatric patients only) correlated inversely with histological assessed disease severity. Using in situ hybridization followed by image analysis, the expression level estimates of miR-21 and miR-126 correlated with histological assessed disease severity. In conclusion, we found that the expression of miRNAs depends on the age of the patient and/or the severity of the disease, suggesting that miRNAs may contribute to the regulation of inflammation in UC and could be useful biomarkers in the surveillance of disease severity.

Overview of host miRNA properties and their association with epigenetics, long non-coding RNAs, and Xeno-infectious factors

MicroRNA-derived structures play impressive roles in various biological processes. So dysregulation of miRNAs can lead to different human diseases. Recent studies have extended our comprehension of the control of miRNA function and features. Here, we overview some remarkable miRNA properties that have potential implications for the miRNA functions, including different variants of a miRNA called isomiRs, miRNA arm selection/arm switching, and the effect of these factors on miRNA target selection. Besides, we review some aspects of miRNA interactions such as the interaction between epigenetics and miRNA (different miRNAs and their related processing enzymes are epigenetically regulated by multiple DNA methylation enzymes. moreover, DNA methylation could be controlled by diverse mechanisms related to miRNAs), direct and indirect crosstalk between miRNA and lnc (Long Non-Coding) RNAs as a further approach to conduct intercellular regulation called "competing endogenous RNA" (ceRNA) that is involved in the pathogenesis of different diseases, and the interaction of miRNA activities and some Xeno-infectious (virus/bacteria/parasite) factors, which result in modulation of the pathogenesis of infections. This review provides some related studies to a better understanding of miRNA involvement mechanisms and overcoming the complexity of related diseases that may be applicable and useful to prognostic, diagnostic, therapeutic purposes and personalized medicine in the future.

Detection of microRNAs by the combination of Exonuclease-III assisted target recycling amplification and repeated-fishing strategy

A simple but effective method for the detection of miRNAs was proposed by integrating exonuclease-III assisted target recycling amplification and repeated-fishing strategy. In the proposed method, exonuclease-III assisted target recycling amplification reaction is adopted to produce a large amount of DNA fragments with fluorescence group at its 5' end in the presence of the target miRNA, which are then repeatedly fished out from the reaction mixture by a gold foil modified with a capture probe and transferred into a so-called 'product tube'. The amount of the target miRNA can then be determined from the fluorescence measurement of the solution in the 'product tube'. Application to the detection of miRNA-155 in samples of KH-2 and BRSA-2B cells revealed that the proposed method could achieve sensitive and accurate quantification of the target miRNA with a limit of detection of 36 fM and recovery rates in the range from 96.2% to 105%. Its simplicity, sensitivity and resistance to possible fluorescence interferences in complex biological samples make the proposed method a potentially competitive alternative for miRNAs detection in complex biological samples.

Decreased expression of microRNA-17 in hippocampal tissues and blood from mice with depression up-regulates the expression of PAI-1 mRNA and protein

This study determined the expression of plasminogen activator inhibitor-1 (PAI-1) and microRNA (miR)-17 in a mouse depression model. Forty male mice were divided evenly into control and depression groups. A chronic unpredictable mild stress (CUMS) model was constructed. qRT-PCR was used to determine the expression of PAI-1 mRNA and miR-17. Western blotting and ELISA were used to determine expression of PAI-1 protein. Dual luciferase reporter assay was carried out to identify direct interaction between miR-17 and PAI-1 mRNA. The mice with depression had elevated PAI-1 mRNA and protein in hippocampal tissues and blood. Expression of miR-17 was decreased in hippocampal tissues and blood from mice with depression. miR-17 bound with the 3'-UTR of PAI-1 mRNA to regulate its expression. This study demonstrated that miR-17 expression in hippocampal tissues and blood from mice with depression was decreased while expression of PAI-1 mRNA and protein was up-regulated. miR-17 participated in depression in mice by regulating PAI-1.

gga-microRNA-375 negatively regulates the cell cycle and proliferation by targeting Yes-associated protein 1 in DF-1 cells

MicroRNAs (miRNAs/miRs) serve a key role in regulating the cell cycle and inducing tumorigenesis. Subgroup J of the avian leukosis virus (ALV-J) belongs to the family Retroviridae, subfamily Orthoretrovirinae and genus Alpharetrovirus that causes tumors in susceptible chickens. gga-miR-375 is downregulated and Yes-associated protein 1 (YAP1) is upregulated in ALV-J-induced tumors in the livers of chickens, and it has been further identified that YAP1 is the direct target gene of gga-miR-375. In the present study, it was found that ALV-J infection promoted the cell cycle and proliferation in DF-1 cells. As the cell cycle and cell proliferation are closely associated with tumorigenesis, further experiments were performed to determine whether gga-miR-375 and YAP1 were involved in these cellular processes. It was demonstrated that gga-miR-375 significantly inhibited the cell cycle by inhibiting G₁ to S/G₂ stage transition and decreasing cell proliferation, while YAP1 significantly promoted the cell cycle and proliferation. Furthermore, these cellular processes in DF-1 cells were affected by gga-miR-375 through the targeting of YAP1. Collectively, the present results suggested that gga-miR-375, downregulated by ALV-J infection, negatively regulated the cell cycle and proliferation via the targeting of YAP1.

Stress-Induced Morphological, Cellular and Molecular Changes in the Brain-Lessons Learned from the Chronic Mild Stress Model of Depression

Major depressive disorder (MDD) is a severe illness imposing an increasing social and economic burden worldwide. Numerous rodent models have been developed to investigate the pathophysiology of MDD. One of the best characterized and most widely used models is the chronic mild stress (CMS) model which was developed more than 30 years ago by Paul Willner. More than 2000 published studies used this model, mainly to assess novel compounds with potential antidepressant efficacy. Most of these studies examined the behavioral consequences of stress and concomitant drug intervention. Much fewer studies focused on the CMS-induced neurobiological changes. However, the stress-induced cellular and molecular changes are important as they may serve as potential translational biomarkers and increase our understanding of the pathophysiology of MDD. Here, we summarize current knowledge on the structural and molecular alterations in the brain that have been described using the CMS model. We discuss the latest neuroimaging and postmortem histopathological data as well as molecular changes including recent findings on microRNA levels. Different chronic stress paradigms occasionally deliver dissimilar findings, but the available experimental data provide convincing evidence that the CMS model has a high translational value. Future studies examining the neurobiological changes in the CMS model in combination with clinically effective antidepressant drug intervention will likely deliver further valuable information on the pathophysiology of MDD.

Association of miR-155 and Angiotensin Receptor Type 1 Polymorphisms with the Risk of Ischemic Stroke in a Chinese Population

There is increasing evidence suggesting that dysregulation of miR-155 and its target angiotensin receptor type 1 (AT1R) are linked to the incidence of ischemic stroke (IS), but the underlying mechanisms remain to be clarified. In this study, we therefore sought to investigate how miR-155 and AT1R polymorphisms affect IS risk. We included 579 IS patients and 509 age-matched controls in the present analysis, genotyping individuals for the rs767649 polymorphism in miR-155, as well as for the rs1492099 and rs275653 polymorphisms in AT1R via iMLDR-TM genotyping technology. The allele and genotype frequencies for the assessed polymorphisms were comparable in IS patients and controls, without any detectable association between AT1R haplotype and IS risk. We conducted additional trial of ORG 10172 in acute stroke treatment-mediated stratification, which indicated that the AT1R rs1492099 T allele was linked to a decreased risk of large-artery atherosclerosis (LAA) stroke. We further found that those with the AT1R rs275653 AA genotype had a decreased risk of small-artery occlusion (SAO) strokes. We further confirmed elevated miR-155 expression in IS patients, but observed no link between the rs767649 polymorphism and expression of this microRNA. Similarly, rs1492099 and rs275653 polymorphisms did not impact AT1R expression levels. The miR-155 rs767649 polymorphism does not seem to be a key determinant of IS risk, whereas the AT1R rs1492099 polymorphism is linked to reduced LAA-stroke risk, and the rs275653 AA genotype is potentially protective against SAO strokes.

MicroRNAs as Epigenetic Targets of Cigarette Smoke During Embryonic Development

The adverse developmental effects of exposure to Cigarette Smoke (CS) during pregnancy are documented in this paper. These include low birth weight, congenital anomalies, preterm birth, fetal mortality and morbidity. The current biological thought now recognizes that epigenetics represents a fundamental contributing process in embryogenesis, and that the environment can have a profound effect on shaping the epigenome. It has become increasingly recognized that genes encoding microRNAs (miRNAs) might be potential loci for congenital disabilities. One means by which CS can cause developmental anomalies may be through epigenetic mechanisms involving altered miRNA expression. While several studies have focused on genes affected by CS during embryonic/ fetal development, there is a paucity of knowledge on the involvement of miRNAs in this process. This brief review summarizes the current state of knowledge in this area.

The Role and Therapeutic Potential of miRNAs in Colorectal Liver Metastasis

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths worldwide. Liver metastasis is the major cause of CRC patient mortality, occurring in 60% patients with no effective therapies. Although studies have indicated the role of miRNAs in CRC, an in-depth miRNA expression analysis is essential to identify clinically relevant miRNAs and understand their potential in targeting liver metastasis. Here we analyzed miRNA expressions in 405 patient tumors from publicly available colorectal cancer genome sequencing project database. Our analyses showed miR-132, miR-378f, miR-605 and miR-1976 to be the most significantly downregulated miRNAs in primary and CRC liver metastatic tissues, and CRC cell lines. Observations in CRC cell lines indicated that ectopic expressions of miR-378f, -605 and -1976 suppress CRC cell proliferation, anchorage independent growth, metastatic potential, and enhance apoptosis. Consistently, CRC patients with higher miR-378f and miR-1976 levels exhibited better survival. Together, our data suggests an anti-tumorigenic role of these miRNAs in CRC and warrant future in vivo evaluation of the molecules for developing biomarkers or novel therapeutic strategies.

Downregulation of microRNA-129-5p increases the risk of intervertebral disc degeneration by promoting the apoptosis of nucleus pulposus cells via targeting BMP2

miR-129-5p is implicated in many diseases, such as laryngeal cancer and breast cancer. In this study, we studied the mechanism underlying the role of BMP2 in intervertebral disc degeneration (IDD). We used a luciferase assay system to determine the relationship between BMP2 and miR-129-5 expression. In addition, Western blot and real-time PCR were used to confirm the regulatory relationship between miR-129-5p and its targets, while flow cytometry was used to evaluate the effect of miR-129-5p on the apoptosis of neural progenitor cells (NPCs). BMP2 was confirmed as a direct target of miR-129-5p. Furthermore, the expression of miR-129 was downregulated along with upregulated BMP2 expression in IDD patients. Meanwhile, BMP2 was validated as the target of miR-129-5p in cells transfected with miR-129-5p and BMP2 siRNA. Also, compared with NPCs transfected with blank/scramble controls or miR-129-5p inhibitors, the NPCs treated with miR-129-5p mimics or BMP2 siRNA exhibited evidently elevated viability and inhibited apoptosis. The data demonstrated that miR-129-5p was poorly expressed in IDD patients, and the dysregulation of miR-129-5p might contribute to the development of IDD by targeting BMP2 expression.

sRNA-pathway genes regulating myxobacterial development exhibit clade-specific evolution

Small non-coding RNAs (sRNAs) control bacterial gene expression involved in a wide range of important cellular processes. In the highly social bacterium Myxococcus xanthus, the sRNA Pxr prevents multicellular fruiting-body development when nutrients are abundant. Pxr was discovered from the evolution of a developmentally defective strain (OC) into a developmentally proficient strain (PX). In OC, Pxr is constitutively expressed and blocks development even during starvation. In PX, one mutation deactivates Pxr allowing development to proceed. We screened for transposon mutants that suppress the OC defect and thus potentially reveal new Pxr-pathway components. Insertions significantly restoring development were found in four genes-rnd, rnhA, stkA and Mxan_5793-not previously associated with an sRNA activity. Phylogenetic analysis suggests that the Pxr pathway was constructed within the Cystobacterineae suborder both by co-option of genes predating the Myxococcales order and incorporation of a novel gene (Mxan_5793). Further, the sequence similarity of rnd, rnhA and stkA homologs relative to M. xanthus alleles was found to decrease greatly among species beyond the Cystobacterineae suborder compared to the housekeeping genes examined. Finally, ecological context differentially affected the developmental phenotypes of distinct mutants, with implications for the evolution of development in variable environments.

Grape seed proanthocyanidins inhibit proliferation of pancreatic cancer cells by modulating microRNA expression

MicroRNAs (miRNAs) are small non-coding RNAs of 18–25 nucleotides that modulate gene expression at the post-transcriptional level. Grape seed proanthocyanidins (GSPs), which are biologically active components in grape seeds, have been demonstrated to exhibit anticancer effects. The current study investigated whether GSPs can regulate miRNA expression and the possible anticancer molecular mechanisms of GSPs. Pancreatic cancer (PC) cell samples, SS3, SS12 and SS24, were treated with 20 µg/ml GSPs for 3, 12 and 24 h, respectively. Control samples, SC3, SC12 and SC24, were also prepared. Using miRNA-seq, transcriptome analysis identified 24, 83 and 83 differentially expressed (DE) miRNAs in SS3 vs. SC3, SS12 vs. SC12 and SS24 vs. SC24, respectively. This indicated that treatment with GSPs could modulate the expression of miRNAs. Subsequently, 74, 598 and 1,204 target genes for the three sets of DE miRNAs were predicted. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed that multiple target genes were associated with the proliferation and apoptosis of PC cells. In addition, a network was constructed of the DE miRNAs and the target genes associated with PC. The associations identified suggested that treatment with GSPs may inhibit the proliferation of PC cells through the modulation of miRNA expression.

The putative tumour suppressor miR-1-3p modulates prostate cancer cell aggressiveness by repressing E2F5 and PFTK1

BACKGROUND

Previous studies report that miR-1-3p, a member of the microRNA-1 family (miR-1), and functions as a tumor suppressor in several different cancers. However, little is known regarding the biological role and intrinsic regulatory mechanisms of miR-1-3p in prostate cancer (PCa).

METHODS

In this study, the expression levels of miR-1-3p were first examined in PCa cell lines and tumor tissues by RT-qPCR and bioinformatics. The in vitro and in vivo functional effect of miR-1-3p was examined further. A luciferase reporter assay was conducted to confirm target associations.

RESULTS

We found that miR-1-3p was significantly downregulated in advanced PCa tissues and cell lines. Low miR-1-3p levels were strongly associated with aggressive clinicopathological features and poor prognosis in PCa patients. Ectopic expression of miR-1-3p in 22RV1 and LncaP cells was sufficient to prevent tumor cell growth and cell cycle progression in vitro and in vivo. Further mechanistic studies revealed that miR-1-3p could directly target the mRNA 3'- untranslated region (3'- UTR) of two central cell cycle genes, E2F5 and PFTK1, and could suppress their mRNA and protein expression. In addition, knockdown of E2F5 and PFTK1 mimicked the tumor-suppressive effects of miR-1-3p overexpression on PCa progression. Conversely, concomitant knockdown of miR-1-3p and E2F5 and PFTK1 substantially reversed the inhibitory effects of either E2F5 or PFTK1 silencing alone.

CONCLUSION

These data highlight an important role for miR-1-3p in the regulation of proliferation and cell cycle in the molecular etiology of PCa and indicate the potential for miR-1-3p in applications furthering PCa prognostics and therapeutics.

Inhibition of MicroRNA-155 Supports Endothelial Tight Junction Integrity Following Oxygen-Glucose Deprivation

BACKGROUND

Brain microvascular endothelial cells form a highly selective blood brain barrier regulated by the endothelial tight junctions. Cerebral ischemia selectively targets tight junction protein complexes, which leads to significant damage to cerebral microvasculature. Short noncoding molecules called microRNAs are implicated in the regulation of various pathological states, including endothelial barrier dysfunction. In the present study, we investigated the influence of microRNA-155 (miR-155) on the barrier characteristics of human primary brain microvascular endothelial cells (HBMECs).

METHODS AND RESULTS

Oxygen-glucose deprivation was used as an in vitro model of ischemic stroke. HBMECs were subjected to 3 hours of oxygen-glucose deprivation, followed by transfections with miR-155 inhibitor, mimic, or appropriate control oligonucleotides. Intact normoxia control HBMECs and 4 oxygen-glucose deprivation-treated groups of cells transfected with appropriate nucleotide were subjected to endothelial monolayer electrical resistance and permeability assays, cell viability assay, assessment of NO and human cytokine/chemokine release, immunofluorescence microscopy, Western blot, and polymerase chain reaction analyses. Assessment of endothelial resistance and permeability demonstrated that miR-155 inhibition improved HBMECs monolayer integrity. In addition, miR-155 inhibition significantly increased the levels of major tight junction proteins claudin-1 and zonula occludens protein-1, while its overexpression reduced these levels. Immunoprecipitation and colocalization analyses detected that miR-155 inhibition supported the association between zonula occludens protein-1 and claudin-1 and their stabilization at the HBMEC membrane. Luciferase reporter assay verified that claudin-1 is directly targeted by miR-155.

CONCLUSIONS

Based on these results, we conclude that miR-155 inhibition-induced strengthening of endothelial tight junctions after oxygen-glucose deprivation is mediated via its direct target protein claudin-1.

gga-miR-451 Negatively Regulates Mycoplasma gallisepticum (HS Strain)-Induced Inflammatory Cytokine Production via Targeting YWHAZ

Mycoplasma gallisepticum (MG) is the most economically significant mycoplasma pathogen of poultry that causes chronic respiratory disease (CRD) in chickens. Although miRNAs have been identified as a major regulator effect on inflammatory response, it is largely unclear how they regulate MG-induced inflammation. The aim of this study was to investigate the functional roles of gga-miR-451 and identify downstream targets regulated by gga-miR-451 in MG infection of chicken. We found that the expression of gga-miR-451 was significantly up-regulated during MG infection of chicken embryo fibroblast cells (DF-1) and chicken embryonic lungs. Overexpression of gga-miR-451 decreased the MG-induced inflammatory cytokine production, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), whereas inhibition of gga-miR-451 had the opposite effect. Gene expression data combined with luciferase reporter assays demonstrated that tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ) was identified as a direct target of gga-miR-451 in the context of MG infection. Furthermore, upregulation of gga-miR-451 significantly inhibited the MG-infected DF-1 cells proliferation, induced cell-cycle arrest, and promoted apoptosis. Collectively, our results demonstrate that gga-miR-451 negatively regulates the MG-induced production of inflammatory cytokines via targeting YWHAZ, inhibits the cell cycle progression and cell proliferation, and promotes cell apoptosis. This study provides a better understanding of the molecular mechanisms of MG infection.

MicroRNA-27a participates in the pathological process of depression in rats by regulating VEGFA

The present study aimed to determine the expression of vascular endothelial growth factor A (VEGFA) and microRNA (miRNA/miR)-27a in hippocampal tissues, and serum from a depression model of rats. In addition, the present study aimed to understand the mechanism of regulation of miR-27a in depression. A total of 40 male rats were selected, and divided into the control and depression model groups. The rats in the model group were subjected to 14 types of stimulations to model depression. By determining the body weight, syrup consumption rate and open field test score, the extent of depression in the rats was evaluated. Quantitative-polymerase chain reaction was used to determine the expression of VEGFA mRNA and miR-27a in hippocampal tissues, and serum. ELISA was used to measure the content of VEGFA protein in serum, while western blotting was employed to determine the expression of VEGFA protein in hippocampal tissues. A dual luciferase assay was carried out to identify the interactions between VEGFA mRNA and miR-27a. The rats in the depression model group showed depression symptoms and the depression model was successfully constructed. Rats with depression had lower VEGFA mRNA and protein expression in the hippocampus, and peripheral blood compared with the control group. Rats in the depression model group had reduced levels of miR-27a in the hippocampus and peripheral blood, which may be associated with the levels of VEGFA. miR-27a was able to bind with the 3′-untranslated region of VEGFA mRNA to regulate its expression. The present study demonstrated that miR-27a expression in hippocampal tissues and blood from rats with depression is upregulated, while the expression of VEGFA mRNA and protein is downregulated. miR-27a may participate in the pathological process of depression in rats by regulating VEGFA.

Silencing a Multifunctional microRNA Is Beneficial for Stroke Recovery

Stroke-induced endothelial cell injury leads to destruction of cerebral microvasculature and significant damage to the brain tissue. A subacute phase of cerebral ischemia is associated with regeneration involving the activation of vascular remodeling, neuroplasticity, neurogenesis, and neuroinflammation processes. Effective restoration and improvement of blood supply to the damaged brain tissue offers a potential therapy for stroke. microRNAs (miRNAs) are recently identified small RNA molecules that regulate gene expression and significantly influence the essential cellular processes associated with brain repair following stroke. A number of specific miRNAs are implicated in regulating the development and propagation of the ischemic tissue damage as well as in mediating post-stroke regeneration. In this review, I discuss the functions of the miRNA miR-155 and the effect of its in vivo inhibition on brain recovery following experimental cerebral ischemia. The article introduces new and unexplored approach to cerebral regeneration: regulation of brain tissue repair through a direct modulation of specific miRNA activity.

Covalent Strategies for Targeting Messenger and Non-Coding RNAs: An Updated Review on siRNA, miRNA and antimiR Conjugates

Oligonucleotide-based therapy has become an alternative to classical approaches in the search of novel therapeutics involving gene-related diseases. Several mechanisms have been described in which demonstrate the pivotal role of oligonucleotide for modulating gene expression. Antisense oligonucleotides (ASOs) and more recently siRNAs and miRNAs have made important contributions either in reducing aberrant protein levels by sequence-specific targeting messenger RNAs (mRNAs) or restoring the anomalous levels of non-coding RNAs (ncRNAs) that are involved in a good number of diseases including cancer. In addition to formulation approaches which have contributed to accelerate the presence of ASOs, siRNAs and miRNAs in clinical trials; the covalent linkage between non-viral vectors and nucleic acids has also added value and opened new perspectives to the development of promising nucleic acid-based therapeutics. This review article is mainly focused on the strategies carried out for covalently modifying siRNA and miRNA molecules. Examples involving cell-penetrating peptides (CPPs), carbohydrates, polymers, lipids and aptamers are discussed for the synthesis of siRNA conjugates whereas in the case of miRNA-based drugs, this review article makes special emphasis in using antagomiRs, locked nucleic acids (LNAs), peptide nucleic acids (PNAs) as well as nanoparticles. The biomedical applications of siRNA and miRNA conjugates are also discussed.

MicroRNA-155 is a potential molecular marker of natural killer/T-cell lymphoma

Natural killer/T-cell lymphoma (NKTCL) is characterized by its highly aggressive nature and rapid progression. MicroRNAs (miRNAs) play key roles in the development of NKTCL. We utilized next-generation Solexa high-throughput sequencing to compare miRNA expression in the SNK-6 and YTS NKTCL cell lines with expression in normal NK cells. We found that 195 miRNAs were upregulated in the SNK-6 cells and 286 miRNAs were upregulated in the YTS cells. Based on those results, we selected six miRNAs, including miRNA-155, and confirmed their expression using real-time polymerase chain reaction. Expression of miRNA-155 was higher in SNK-6 and YKS cells than in normal NK cells. We next determined the levels of miRNA-155 in the serum of healthy individuals and NKTCL patients, and correlated its expression with clinical parameters and inflammatory factors detected using enzyme-linked immunoabsorbent assays. Levels of miRNA-155 were higher in NKTCL patients' serum than in serum from healthy individuals. miRNA-155 expression was higher in patients with stable or progressive disease (SD+PD) than in those with partial or complete remission (PR+CR). While further studies are needed to clarify the underlying molecular mechanisms, it appears miRNA-155 may be a molecular marker of NKTCL.

MicroRNAs Reprogram Tumor Immune Response

Endogenously produced microRNAs (miRNAs) are predicted to regulate the translation of over two-thirds all human gene transcripts. Certain microRNAs regulate expression of genes that are critically involved in both innate and adaptive immune responses. miRNAs have been demonstrated to function as crucial regulators of immune response under both physiological and pathological conditions. Specifically, different miRNAs have been reported to have a role in controlling the development and the functions of tumor-associated immune cells. Immune cells represent a highly attractive target for microRNA gene therapy approaches, as these cells can be isolated, treated, and then reintroduced into patients. In this chapter, we will discuss how recent discoveries on the roles of microRNAs in immune-regulation will advance the field of cancer immunology and immunotherapy.

MicroRNAs as potential prognosticators of neurological outcome in out-of-hospital cardiac arrest patients

Out-of-hospital cardiac arrest survival rates have increased due to advancement in resuscitative measures, yet approximately 90% of survivors ultimately die or have severe neurologic dysfunction caused by ischemic injury. Currently, there are few early prognostic indicators of which patients have possibility of meaningful recovery. This leads to uncertainty for families and clinicians, as well as aggressive, invasive and expensive treatments despite medical futility. Several biomarkers investigated in traumatic brain injury have shown prognostication potential in ischemic brain injury. miRNAs, small noncoding RNAs responsible for gene regulation, have been studied in cardiovascular diseases, and have shown prognostication potential due to tissue specificity and stability in circulation. This review discusses available evidence on miRNAs prognosticating neurological outcomes after out-of-hospital cardiac arrest.

Activation of miR-34a impairs autophagic flux and promotes cochlear cell death via repressing ATG9A: implications for age-related hearing loss

Age-related hearing loss is a major unresolved public health problem. We have previously elucidated that the activation of cochlear miR-34a is correlated with age-related hearing loss in C57BL/6 mice. A growing body of evidence points that aberrant autophagy promotes cell death during the development of multiple age-related diseases. The aim of this study was to investigate the role of miR-34a-involved disorder of autophagy in the pathogenesis of age-related hearing loss. Our results showed that miR-34a expression was markedly upregulated in the aging cochlea accompanied with impairment of autophagic flux. In the inner ear HEI-OC1 cell line, miR-34a overexpression resulted in an accumulation of phagophores and impaired autophagosome-lysosome fusion, and led to cell death subsequently. Notably, autophagy-related protein 9A (ATG9A), an autophagy protein, was significantly decreased after miR-34a overexpression. Knockdown of ATG9A inhibited autophagy flux, which is similar to the effects of miR-34a overexpression. Moreover, ursodeoxycholic acid significantly rescued miR-34a-induced HEI-OC1 cell death by restoring autophagy activity. Collectively, these findings increase our understanding of the biological effects of miR-34a in the development of age-related hearing loss and highlight miR-34a as a promising therapeutic target for its treatment.

Animal Models to Study MicroRNA Function

The discovery of the microRNAs, lin-4 and let-7 as critical mediators of normal development in Caenorhabditis elegans and their conservation throughout evolution has spearheaded research toward identifying novel roles of microRNAs in other cellular processes. To accurately elucidate these fundamental functions, especially in the context of an intact organism, various microRNA transgenic models have been generated and evaluated. Transgenic C. elegans (worms), Drosophila melanogaster (flies), Danio rerio (zebrafish), and Mus musculus (mouse) have contributed immensely toward uncovering the roles of multiple microRNAs in cellular processes such as proliferation, differentiation, and apoptosis, pathways that are severely altered in human diseases such as cancer. The simple model organisms, C. elegans, D. melanogaster, and D. rerio, do not develop cancers but have proved to be convenient systesm in microRNA research, especially in characterizing the microRNA biogenesis machinery which is often dysregulated during human tumorigenesis. The microRNA-dependent events delineated via these simple in vivo systems have been further verified in vitro, and in more complex models of cancers, such as M. musculus. The focus of this review is to provide an overview of the important contributions made in the microRNA field using model organisms. The simple model systems provided the basis for the importance of microRNAs in normal cellular physiology, while the more complex animal systems provided evidence for the role of microRNAs dysregulation in cancers. Highlights include an overview of the various strategies used to generate transgenic organisms and a review of the use of transgenic mice for evaluating preclinical efficacy of microRNA-based cancer therapeutics.

gga-miR-99a targets SMARCA5 to regulate Mycoplasma gallisepticum (HS strain) infection by depressing cell proliferation in chicken

Mycoplasma gallisepticum (MG), one of the primary etiological agents of poultry chronic respiratory disease, has caused significant economic losses worldwide, and increasing evidence has recently indicated that miRNAs are involved in its microbial pathogenesis. gga-miR-99a, a member of the miR-99 family, plays an essential role in a variety of diseases. Through miRNA Solexa sequencing, we previously found that gga-miR-99a is significantly down-regulated in the lungs of MG-infected chicken embryos. In this study, we further verified that the expression of gga-miR-99 was significantly down-regulated in both MG-infected lungs and a chicken embryonic fibroblast cell line (DF-1) by qPCR. Moreover, we predicted and validated SMARCA5 as its target gene through a luciferase reporter assay, qPCR, and western blot analysis. The over-expression of gga-miR-99a significantly depressed SMARCA5 expression, whereas a gga-miR-99a inhibitor enhanced the expression of SMARCA5. Inversely, SMARCA5 was significantly up-regulated and gga-miR-99a was obviously down-regulated in MG-HS-infected chicken embryonic lungs and DF-1 cells. At 72h post-transfection, the over-expression of gga-miR-99a significantly repressed the proliferation of DF-1 cells by inhibiting the transition from the G1 phase to the S and G2 phases. This study reveals that gga-miR-99a plays a key role in MG infection through the regulation of SMARCA5 expression and provides new insights regarding the mechanisms of MG pathogenesis.

The regulatory role of miRNAs on VDR in breast cancer

Triple negative breast cancer (TNBC) has been associated with the lack of three hormone receptors; estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). However, a host of other steroid hormone receptors such as vitamin D receptor (VDR) is present in TNBC, and the role of these hormone receptors in breast tumorigenesis is unclear. The levels of microRNAs (miRNAs) are also expressed differently than in normal mammary epithelial cells. miRNAs are regulatory RNAs involved in various cellular functions, mainly gene silencing. Here, we reviewed the literature surrounding miRNAs in breast cancer, and performed in silico analysis to determine whether there was a correlation between levels of VDR in relation to miRNAs important in breast cancer development and tumorigenesis. We identified three miRNAs of interest, specifically, miR-23, miR-124, and miR-125. Through this research we determined the possibility that these miRNAs play an important role in controlling VDR activity and by virtue the development of breast cancer.

MicroRNA‑296‑5p downregulated AKT2 to inhibit hepatocellular carcinoma cell proliferation, migration and invasion

Hepatocellular carcinoma (HCC) is the fifth most common malignancy in men, and the seventh in women worldwide. Despite development in the therapy of HCC, the prognosis of HCC patients remains poor. Therefore, it is of great significance to explore the molecular mechanism underlying HCC progression, and investigate novel therapeutic strategies for the treatments of HCC. MicroRNAs (miRs) are known to be involved in the pathogenesis of HCC. The present study aimed to investigate the expression patterns and potential roles of miR‑296‑5p in HCC. Results revealed that miR‑296‑5p was frequently downregulated in HCC tissue samples and cell lines. Additionally, reduced miR‑296‑5p expression levels were correlated with tumor size, TNM stage and metastasis in HCC. Gain‑of‑function demonstrated that miR‑296‑5p inhibited HCC cell proliferation, migration and invasion in vitro. Furthermore, AKT2 was identified as a novel direct and functional target of miR‑296‑5p in HCC. These findings indicated that miR‑296‑5p/AKT2 axis serves important roles in HCC carcinogenesis and progression, and miR‑296‑5p/AKT2 based target therapy hampers HCC tumor growth and metastasis.

The putative tumor suppressor microRNA-30a-5p modulates clear cell renal cell carcinoma aggressiveness through repression of ZEB2

Clear cell renal cell carcinoma (ccRCC), the most common subtype of renal cell carcinoma, can easily invade local tissues and metastasize, and is resistant to currently available treatments. Recent studies profiling microRNA expression in ccRCC have suggested miR-30a-5p may be deregulated in these cancer cells. To determine its role and mechanism of action in ccRCC, miR-30-5p expression levels were quantified and functions were analyzed using in vitro and in vivo experiments and bioinformatics. A decrease in miR-30a-5p expression was frequently noted in ccRCC cells and tissues. Importantly, low miR-30a-5p levels were significantly associated with a poor ccRCC patient prognosis. Stable overexpression of miR-30a-5p in 769-P cells was sufficient to prevent cellular proliferation and invasion in vitro and in vivo. Upon further examination, it was found that miR-30a-5p directly targeted the 3'-UTR of ZEB2 and suppressed ccRCC cell epithelial-mesenchymal transition. In addition, miR-30a-5p may be downregulated by the long non-coding RNA DLEU2. Taken together, these data reveal an important role for miR-30a-5p in the regulation of ccRCC proliferation and invasion, and indicate the potential for miR-30a-5p in applications furthering ccRCC prognostics and therapeutics.

Systemic antimiR-337-3p delivery inhibits cerebral ischemia-mediated injury

Modulation of miRNA expression has been shown to be beneficial in the context of multiple diseases. The purpose of this study was to determine if an inhibitor of miR-337-3p is neuroprotective for hypoxic injury after tail vein injection. We evaluated miR-337-3p expression levels and in brain tissue in vivo before and after permanent middle cerebral artery occlusion (pMCAO) in mice. Subsequently, a custom locked nucleic acid (LNA) antimir-337-3p oligonucleotide was developed and tested in vitro after induction of oxygen glucose-deprivation (OGD) and in vivo by injection into the mouse tail vein for 3 consecutive days before pMCAO. Ischemic lesion volume was measured by TTC staining. We show that systemically administered LNA antimir-337-3p crosses the blood brain-brain-barrier (BBB), penetrates into neurosn, downregulates endogenous miR-337-3p expression and reduces ischemic brain injury. The findings support the use of similar antimir-LNA constructs as novel therapies in neurological disease.

c-MYC-Making Liver Sick: Role of c-MYC in Hepatic Cell Function, Homeostasis and Disease

Over 35 years ago, c-MYC, a highly pleiotropic transcription factor that regulates hepatic cell function, was identified. In recent years, a considerable increment in the number of publications has significantly shifted the way that the c-MYC function is perceived. Overexpression of c-MYC alters a wide range of roles including cell proliferation, growth, metabolism, DNA replication, cell cycle progression, cell adhesion and differentiation. The purpose of this review is to broaden the understanding of the general functions of c-MYC, to focus on c-MYC-driven pathogenesis in the liver, explain its mode of action under basal conditions and during disease, and discuss efforts to target c-MYC as a plausible therapy for liver disease.

Targeting noncoding RNAs in disease

Many RNA species have been identified as important players in the development of chronic diseases, including cancer. Over the past decade, numerous studies have highlighted how regulatory RNAs such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) play crucial roles in the development of a disease state. It is clear that the aberrant expression of miRNAs promotes tumor initiation and progression, is linked with cardiac dysfunction, allows for the improper physiological response in maintaining glucose and insulin levels, and can prevent the appropriate integration of neuronal networks, resulting in neurodegenerative disorders. Because of this, there has been a major effort to therapeutically target these noncoding RNAs. In just the past 5 years, over 100 antisense oligonucleotide-based therapies have been tested in phase I clinical trials, a quarter of which have reached phase II/III. Most notable are fomivirsen and mipomersen, which have received FDA approval to treat cytomegalovirus retinitis and high blood cholesterol, respectively. The continued improvement of innovative RNA modifications and delivery entities, such as nanoparticles, will aid in the development of future RNA-based therapeutics for a broader range of chronic diseases. Here we summarize the latest promises and challenges of targeting noncoding RNAs in disease.

Computational study of 'HUB' microRNA in human cardiac diseases

MicroRNAs (miRNAs) are small non-coding RNAs ~22 nucleotides long that do not encode for proteins but have been reported to influence gene expression in normal and abnormal health conditions. Though a large body of scientific literature on miRNAs exists, their network level profile linking molecules with their corresponding phenotypes, is less explored. Here, we studied a network of 191 human miRNAs reported to play a role in 30 human cardiac diseases. Our aim was to study miRNA network properties like hubness and preferred associations, using data mining, network graph theory and statistical analysis. A total of 16 miRNAs were found to have a disease node connectivity of >5 edges (i.e., they were linked to more than 5 diseases) and were considered hubs in the miRNAcardiac disease network. Alternatively, when diseases were considered as hubs, >10 of miRNAs showed up on each ‘disease hub node’. Of all the miRNAs associated with diseases, 19 miRNAs (19/24= 79.1% of upregulated events) were found to be upregulated in atherosclerosis. The data suggest micro RNAs as early stage biological markers in cardiac conditions with potential towards microRNA based therapeutics.

MicroRNA-155 promotes bladder cancer growth by repressing the tumor suppressor DMTF1

MicroRNA-155 (miR-155) is dysregulated in human cancers. In this study, we reported that miR-155 was over-expressed in bladder cancer tissues. We found that miR-155 promoted cell proliferation in vitro and tumorigenesis in vivo. MiR-155 directly reduced the expression of the tumor suppressor DMTF1. The expression of DMTF1 was decreased in bladder cancer tissues. Similar to the restoring miR-155 expression, knockdown of DMTF1 promoted cell growth and cell cycle progression, whereas DMTF1 over-expression rescued the effect of miR-155. Moreover, we investigated DMTF1-Arf-p53 pathway and found that DMTF1 worked in both p53-dependent and p53-independent manners. Taken together, our findings suggested that miR-155 functions as a tumor promoter in bladder cancer, which is partially through repressing DMTF1 expression. The identification of miR-155 and its novel target DMTF1 will be valuable in developing diagnostic markers and therapeutic applications for bladder cancer.