A parsimonious model for gene regulation by miRNAs

The Role of Dynamic miRISC During Neuronal Development

Activity-dependent protein synthesis plays an important role during neuronal development by fine-tuning the formation and function of neuronal circuits. Recent studies have shown that miRNAs are integral to this regulation because of their ability to control protein synthesis in a rapid, specific and potentially reversible manner. miRNA mediated regulation is a multistep process that involves inhibition of translation before degradation of targeted mRNA, which provides the possibility to store and reverse the inhibition at multiple stages. This flexibility is primarily thought to be derived from the composition of miRNA induced silencing complex (miRISC). AGO2 is likely the only obligatory component of miRISC, while multiple RBPs are shown to be associated with this core miRISC to form diverse miRISC complexes. The formation of these heterogeneous miRISC complexes is intricately regulated by various extracellular signals and cell-specific contexts. In this review, we discuss the composition of miRISC and its functions during neuronal development. Neurodevelopment is guided by both internal programs and external cues. Neuronal activity and external signals play an important role in the formation and refining of the neuronal network. miRISC composition and diversity have a critical role at distinct stages of neurodevelopment. Even though there is a good amount of literature available on the role of miRNAs mediated regulation of neuronal development, surprisingly the role of miRISC composition and its functional dynamics in neuronal development is not much discussed. In this article, we review the available literature on the heterogeneity of the neuronal miRISC composition and how this may influence translation regulation in the context of neuronal development.

Gene Silencing Mechanisms Revealed by Dynamics of Guide, Target, and Duplex Binding to Argonaute

Argonaute (Ago) protein plays a central role in silencing gene expression by binding a "guide" strand to the base-pair with a complementary mRNA and degrading the mRNA. The current understanding of how Ago-guide and Ago-guide-mRNA complexes assemble is based mainly on static crystal structures; the associated kinetic pathways remain unknown/unclear. By simulating the successive binding of guide/target strand to Thermus thermophilus Ago (TtAgo) and computing the respective free energy landscapes, we directly visualize how TtAgo silencing complexes form and function. We show that the guide binding rate depends on its initial loading position onto TtAgo. Subsequent target recognition beyond the scissile 10-11 nucleotides must overcome a substantial energy barrier for TtAgo's nucleotide-binding groove to expand widely. This work reveals novel roles for the core TtAgo domains and shows how the kinetic barriers that must be overcome for critical structural changes to occur lead to target repression/cleavage.

Enrichment of Exosome-Like Extracellular Vesicles from Plasma Suitable for Clinical Vesicular miRNA Biomarker Research

Exosome-like extracellular vesicles (ELVs) contain biomolecules that have potential as diagnostic biomarkers, such as proteins, micro-RNAs (miRNAs), and lipids. However, it is difficult to enrich ELVs consistently with high yield and purity from clinical samples, which hampers the development of ELV biomarkers. This is particularly true for miRNAs in protein-rich plasma. Hence, we modified ELV isolation protocols of three commercially available polymer-precipitation-based kits using proteinase K (PK) treatment to quantify ELV-associated miRNAs in human plasma. We compared the yield, purity, and characteristics of enriched plasma ELVs, and measured the relative quantity of three selected miRNAs (miR-30c, miR-126, and miR-192) in ELVs using six human plasma samples. Compared with the original protocols, we demonstrated that ELVs can be isolated with PK treatment with high purity (i.e., lack of non-exosomal proteins and homogeneous size of vesicles) and yield (i.e., abundancy of exosomal markers), which were dependent on kits. Using the kit with the highest purity and yield with PK treatment, we successfully quantified ELV miRNAs (levels of 45%–65% in total plasma) with acceptable variability. Collectively, ELV enrichment using the modified easy-to-use method appears suitable for the analysis of miRNAs, although its clinical applicability needs to be confirmed in larger clinical studies.

Low expression of microRNA-125b enhances the expression of STAT3 and contributes to cholesteatoma growth

Introduction

MicroRNA-125b has been found to be down-regulated in many types of malignant tumours and diseases with excessive proliferation of keratinocytes, such as cutaneous squamous cell carcinoma and psoriasis. Cholesteatoma, which is mainly composed of keratinocytes, also has characteristics of abnormal proliferation similar to a malignant tumour. However, the expression and regulatory mechanisms of miR-125b and its downstream genes in cholesteatoma have not been clarified.

Material and methods

Real time fluorescence quantitative PCR was applied to detect the expression of miR-125b in the cholesteatoma and corresponding retroauricular skin. Immunohistochemical staining and western blot were used to detect signal transducers and activators of transcription 3 (STAT3) and the downstream gene cyclin D1, survivin, and vascular endothelial growth factor (VEGF) in the cholesteatoma and corresponding retroauricular skin. The targeted regulatory relationship between miR-125b and STAT3 was confirmed by dual luciferase reporter assay. Proliferation and apoptosis of transfected HaCaT cells were detected by MTS, cell cycle, and apoptosis assays.

Results

We observed down-regulation of miR-125b and up-regulation of STAT3, cyclin D1, survivin, and VEGF in cholesteatoma tissues. STAT3 was a direct target gene of miR-125b. Inhibition of miR-125b enhanced STAT3 and its downstream genes expression, promoted HaCaT cell proliferation, and inhibited apoptosis.

Conclusions

The results of this study demonstrate that miR-125b can influence the growth of cholesteatoma by targeting STAT3 and its downstream genes, including cyclin D1, survivin, and VEGF, thus providing an opportunity to establish new medical therapy strategies and facilitating further study of the pathogenesis of cholesteatoma.

miR-10a-5p is increased in atopic dermatitis and has capacity to inhibit keratinocyte proliferation

BACKGROUND

miR-10a-5p has been shown to regulate cancer cell proliferation and invasiveness and endothelial cell inflammatory responses. The function of miR-10a-5p in the skin has not been previously studied. The aim of the current study was to examine miR-10a-5p expression, regulation, and function in keratinocytes (KCs) in association with atopic dermatitis (AD).

METHODS

The expression of miR-10a-5p and its target genes was analyzed using RT-qPCR, mRNA array analysis, in situ hybridization, and immunofluorescence. The transfection of miRNA mimics, cell cycle distribution analysis, and luciferase assays was used to study miR-10a-5p functions in human primary KCs.

RESULTS

miR-10a-5p was found to be upregulated in lesional skin from patients with AD and in proliferating KCs. Array and pathway analysis of IL-1β-stimulated KCs revealed that miR-10a-5p inhibited many genes that affect cell cycle progression and only a few inflammation-related genes. Accordingly, fewer cells in S-phase and reduced proliferation were detected as characteristics of miR-10a-5p-transfected KCs. The influence of miR-10a-5p on cell proliferation was also evident in KCs induced by AD-related cytokines, including IL-4, IL-17, and IL-1β, as measured by the capacity to strongly suppress the expression of the proliferation marker Ki-67. Among AD-related putative direct target genes, we verified hyaluronan synthase 3, a damage-associated positive regulator of KC migration and proliferation, as a direct target of miR-10a-5p.

CONCLUSIONS

miR-10a-5p inhibits KC proliferation and directly targets hyaluronan synthase 3 and thereby may modulate AD-associated processes in the skin.

MicroRNAs as Potential Biomarkers of Insecticide Exposure: A Review

Insecticides are key weapons for the control of pests. Large scale use of insecticides is harmful to the ecosystem, which is made up of a wide range of species and environments. MicroRNAs (miRNAs) are a class of endogenous single-stranded noncoding small RNAs in length of 20-24 nucleotides (nt), which extensively regulate expression of genes at transcriptional and post-transcriptional levels. The current research on miRNA-induced insecticide resistance reveals that dysregulated miRNAs cause significant changes in detoxification genes, particularly cytochrome P450s. Meanwhile, insecticide-induced changes in miRNAs are related to the decline of honeybees and threatened the development of zebrafish and other animals. Additionally, miRNAs are involved in insecticide-induced cytotoxicity, and dysregulated miRNAs are associated with human occupational and environmental exposure to insecticides. Therefore, miRNAs are valuable novel biomarkers of insecticide exposure, and they are potential factors to explain the toxicological effects of insecticides.

Mechanisms and Consequences of Oxygen and Carbon Dioxide Sensing in Mammals

Molecular oxygen (O₂) and carbon dioxide (CO₂) are the primary gaseous substrate and product of oxidative phosphorylation in respiring organisms, respectively. Variance in the levels of either of these gasses outside of the physiological range presents a serious threat to cell, tissue, and organism survival. Therefore, it is essential that endogenous levels are monitored and kept at appropriate concentrations to maintain a state of homeostasis. Higher organisms such as mammals have evolved mechanisms to sense O₂ and CO₂ both in the circulation and in individual cells and elicit appropriate corrective responses to promote adaptation to commonly encountered conditions such as hypoxia and hypercapnia. These can be acute and transient nontranscriptional responses, which typically occur at the level of whole animal physiology or more sustained transcriptional responses, which promote chronic adaptation. In this review, we discuss the mechanisms by which mammals sense changes in O₂ and CO₂ and elicit adaptive responses to maintain homeostasis. We also discuss crosstalk between these pathways and how they may represent targets for therapeutic intervention in a range of pathological states.

miR-221/222 activate the Wnt/β-catenin signaling to promote triple-negative breast cancer

Triple-negative breast cancer (TNBC), characterized by the lack of expression of the estrogen receptor, the progesterone receptor, and the human epidermal growth factor receptor 2, is an aggressive form of cancer that conveys unpredictable and poor prognosis due to limited treatment options and lack of effective targeted therapies. Wnt/β-catenin signaling is hyperactivated in TNBC, which promotes the progression of TNBC. However, the molecular mechanism of Wnt/β-catenin activation in TNBC remains unknown. Here, we report the drastic overexpression of miR-221/222 in all of four TNBC cell lines and TNBC primary tumor samples from patients. Furthermore, we demonstrate by both ex vivo and xenograft experiments that inhibiting miR-221/222 expression in a TNBC cell line (MDA-MB-231) suppresses its proliferation, viability, epithelial-to-mesenchymal transition, and migration; whereas expressing miR-221/222 in a non-TNBC line (MCF7) promotes all of the above cancer properties. miR-221/222 achieve so by directly repressing multiple negative regulators of the Wnt/β-catenin signaling pathway, including WIF1, SFRP2, DKK2, and AXIN2, to activate the pathway. Notably, the level of miR-221/222 expression is inversely correlated whereas that of WIF1, DKK2, SFRP2, and AXIN2 expression is positively correlated with the patient survival. Last, we show that anti-miR-221/222 significantly increases apoptotic cells with tamoxifen/Wnt3a treatment but not with cyclophosphamide/Wnt3a treatment. These results demonstrate that miR-221/222 activate the Wnt/β-catenin signaling to promote the aggressiveness and TNBC properties of breast cancers, and thus reveal a new prospect for TNBC treatment.

Silica nanoparticles induce spermatocyte cell apoptosis through microRNA-2861 targeting death receptor pathway

Silica nanoparticles (SiNPs) are found in the environmental particulate matter and have been proved to pose an adverse effect on fertility. However, the relationship between miRNA and apoptosis induced by SiNPs in spermatogenesis and its underlying mechanism remains confusing. Therefore, the present study was designed to investigate the toxic effects of SiNPs on spermatogenic cells mediated through miRNAs. Spermatocyte cells were divided into 0 μg/mL and 5 μg/mL SiNPs groups, and the cells were collected and analyzed after passaging for 1, 10, 20, and 30 generations. miRNA profile and mRNA profile of spermatocyte cells were measured after exposure to SiNPs for 30 generations. Further, mimics and inhibitors of miRNA were used to verify the relationship between miRNA and their predicted target genes in the 30th-generation cells. The results showed that the degree of cell apoptosis in the SiNPs group significantly increased in the 30th generation. After exposure to SiNPs for 30 generations, the expression of 15 miRNAs was altered, including 5 upregulated miRNAs and 10 downregulated miRNAs. Of the 15 miRNAs, miR-138 and miR-2861 were related to the death receptor pathway. The miR-2861 mimic could target to regulate the mRNA expression of fas/fasl/ripk1 and increase the protein expression of Fas/FasL/RIPK1/FADD/caspase-8/caspase-3 of spermatogenic cells in the 30th generation, while the miR-138 inhibitor could not. In conclusion, SiNPs could cause apoptosis of spermatocyte cells by inhibiting the expression of miRNA-2861, thereby resulting in the upregulation of mRNA expression of fas/fasl/ripk1 and activating the death receptor pathway of spermatocyte cells. miRNA-2861 could be considered a biomarker of the toxic effect of SiNPs on spermatocyte cells. The main finding: Silica nanoparticles induce apoptosis in spermatocyte cells through microRNA-2861 inhibition, thereby upregulating mRNA expression of fas/fasl/ripk1 and activating the death receptor pathway of spermatocyte cells.

Inhibition of miR-221 alleviates LPS-induced acute lung injury via inactivation of SOCS1/NF-κB signaling pathway

The role of inflammation response has been well documented in the development of acute lung injury (ALI). However, little is known about the functions of miRNAs in the regulation of inflammation in ALI. The aim of this study was to explore the effects of miRNAs in the regulation of inflammation in ALI and to elucidate the biomolecular mechanisms responsible for these effects. The expression profiles of miRNAs in lung tissues from lipopolysaccharide (LPS)-induced ALI mice model were analyzed using a microarray. It was observed that microRNA-221-3p (miR-221) was significantly increased in lung tissues in ALI mice. The inhibition of miR-221 attenuated lung injury including decreased lung W/D weight ratio and lung permeability and survival rates of ALI mice, as well as apoptosis, whereas its agomir-mediated upregulation exacerbated the lung injury. Concomitantly, miR-221 inhibition significantly reduced LPS-induced pulmonary inflammation, while LPS-induced pulmonary inflammation was aggravated by miR-221 upregulation. Of note, suppressor of cytokine signaling-1 (SOCS1), an effective suppressor of the NF-κB signaling pathway, was found to be a direct target of miR-221 in RAW264.7 cells. Overexpression of SOCS1 by pcDNA-SOCS1 plasmids markedly reversed the miR-221 inhibition-mediated inhibitory effects on inflammation and apoptosis in LPS-treated RAW264.7 cells. Finally, it was found that miR-221 inhibition suppressed LPS induced the activation of the NF-κB signaling pathway, as demonstrated by downregulation of phosphorylated-IκBα, p-p65 and upregulation of IκBα, whilst miR-221 overexpression had an opposite result in ALI mice. Our findings demonstrate that inhibition of miR-221 can alleviate LPS-induced inflammation via inactivation of SOCS1/NF-κB signaling pathway in ALI mice.

MicroRNA let-7 regulates the expression of ecdysteroid receptor (ECR) in Hyalomma asiaticum (Acari: Ixodidae) ticks

Background

Ticks are blood-sucking arthropods that can transmit diseases to humans and animals. These arthropods are the second most important vectors of pathogens. MicroRNAs are a class of conserved small noncoding RNAs that play regulatory roles in gene expression at the post-transcriptional level. Molting is an important biological process in arthropods. Research on the molting process is important for understanding tick physiology and control.

Methods

Dual-luciferase reporter assays were used to assess the role of miRNA let-7 in ecdysteroid receptor (ECR) biology. The expression levels of ECR and let-7 were measured by real-time qPCR before and after tick molting. To explore the function of let-7 and ECR, we performed overexpression and knocking down of let-7 and RNAi of ECR in tick nymphs. The biological function of let-7 in molting was explored by injecting nymphs, ten days after engorgement, with let-7 agomir for overexpression and let-7 antagomir for knocking down. The rate of molting was then determined. ECR dsRNA was injected into ticks to evaluate the function of ECR by gene silencing. The expression of ECR and let-7 was measured using RT-qPCR. All data were analyzed using GraphPad Prism v.6.

Results

The results of the luciferase assay using a eukaryotic expression system revealed that ECR was a natural target of let-7. Let-7 overexpressed by agomir affected the rate of molting (P < 0.01) and the period of molting (P < 0.01). Let-7 antagomir for knockdown affected the period of molting (P < 0.01), but there was no effect on the rate of molting (P = 0.27). ECR dsRNA gene silencing significantly affected the rate of molting (P < 0.05).

Conclusions

This study demonstrated that let-7 can regulate the expression of ECR and that let-7 can affect molting in ticks. Our results help to understand the regulation of let-7 by 20-hydroxyecdysone (20E) and will provide a reference for functional analysis studies of microRNAs in ticks.

ΜicroRNA‑421 promotes the progression of non‑small cell lung cancer by targeting HOPX and regulating the Wnt/β‑catenin signaling pathway

MicroRNAs (miRNAs) function as key regulators of numerous types of cancers. miRNA (miR)-421 expression is dysregulated in a variety of tumors; however, its role in non-small cell lung cancer (NSCLC) remains unclear. In the present study, the role and molecular mechanism of miR-421 in NSCLC was investigated. In this study, miRNA (miR)-421 was upregulated in NSCLC tissues and cell lines used the reverse transcriptase quantitative polymerase chain reaction. Ectopic expression of miR-421 significantly promoted cell proliferation in vitro and tumor growth in vivo by promoting cell cycle progression via CCK-8, colony formation, EdU assay, xenograft model and cell cycle assay. In addition, miR-421 inhibited NSCLC cell apoptosis by flow cytometry apoptosis assay, as evidenced by anti-apoptosis gene Bcl-2 and apoptosis gene cleaved caspase-3 and cleaved PARP using western blot assay. Furthermore, miR-421 promoted cell migration and invasion through EMT process using Transwell and western blot assay. It was also demonstrated that miR-421 can directly target HOPX by the EGFP reporter assay and western blot assay. MiR-421 overexpression promoted the protein expression levels of β-catenin, cyclin D1 and c-myc by western blot assay, which are the downstream genes of Wnt pathway. These data indicated that miR-421 may act as an oncogene through the effects of HOPX on the Wnt/β-catenin signaling pathway and may provide insight into the mechanisms underlying carcinogenesis and the identification of potential biomarkers associated with NSCLC.

MicroRNA Involvement in Allergic and Non-Allergic Mast Cell Activation

Allergic inflammation is accompanied by the coordinated expression of numerous genes and proteins that initiate, sustain, and propagate immune responses and tissue remodeling. MicroRNAs (miRNAs) are a large class of small regulatory molecules that are able to control the translation of target mRNAs and consequently regulate various biological processes at the posttranscriptional level. MiRNA profiles have been identified in multiple allergic inflammatory diseases and in the tumor microenvironment. Mast cells have been found to co-localize within the above conditions. More specifically, in addition to being essential in initiating the allergic response, mast cells play a key role in both innate and adaptive immunity as well as in modulating tumor growth. This review summarizes the possible role of various miRNAs in the above-mentioned processes wherein mast cells have been found to be involved. Understanding the role of miRNAs in mast cell activation and function may serve as an important tool in developing diagnostic as well as therapeutic approaches in mast cell-dependent pathological conditions.

Panoramic Visualization of Circulating MicroRNAs Across Neurodegenerative Diseases in Humans

Neurodegenerative diseases (NDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and dementia pose one of the greatest health challenges this century. Although these NDs have been looked at as single entities, the underlying molecular mechanisms have never been collectively visualized to date. With the advent of high-throughput genomic and proteomic technologies, we now have the opportunity to visualize these diseases in a whole new perspective, which will provide a clear understanding of the primary and secondary events vital in achieving the final resolution of these diseases guiding us to new treatment strategies to possibly treat these diseases together. We created a knowledge base of all microRNAs known to be differentially expressed in various body fluids of ND patients. We then used several bioinformatic methods to understand the functional intersections and differences between AD, PD, ALS, and MS. These results provide a unique panoramic view of possible functional intersections between AD, PD, MS, and ALS at the level of microRNA and their cognate genes and pathways, along with the entities that unify and separate them. While the microRNA signatures were apparent for each ND, the unique observation in our study was that hsa-miR-30b-5p overlapped between all four NDS, and has significant functional roles described across NDs. Furthermore, our results also show the evidence of functional convergence of miRNAs which was associated with the regulation of their cognate genes represented in pathways that included fatty acid synthesis and metabolism, ECM receptor interactions, prion diseases, and several signaling pathways critical to neuron differentiation and survival, underpinning their relevance in NDs. Envisioning this group of NDs together has allowed us to propose new ways of utilizing circulating miRNAs as biomarkers  and in visualizing diverse NDs more holistically . The critical molecular insights gained through the discovery of ND-associated miRNAs, overlapping miRNAs, and the functional convergence of microRNAs on vital pathways strongly implicated in neurodegenerative processes can prove immensely valuable in the identifying new generation of biomarkers, along with the development of miRNAs into therapeutics.

MiR-199a-5p Inhibits the Growth and Metastasis of Colorectal Cancer Cells by Targeting ROCK1

Mounting evidence indicates that microRNAs play important roles in the development of various cancers. Aberrant expression of microRNA-199a-5p has been frequently reported in cancer studies; however, the mechanistic details of the role of microRNA-199a-5p in colorectal cancer still remain unclear. Our study aimed to explore the role of microRNA-199a-5p in colorectal cancer cells by targeting Rho-associated coiled coil-containing protein kinase 1. Here, we showed that microRNA-199a-5p was significantly downregulated in colorectal cancer cell lines and tissue samples and was associated with a poor prognostic phenotype. MicroRNA-199a-5p suppressed colorectal cancer cell proliferation, migration, and invasion and induced cell apoptosis. Moreover, we identified Rho-associated coiled coil-containing protein kinase 1 as the direct target of microRNA-199a-5p using luciferase and Western blot assays. Importantly, Rho-associated coiled coil-containing protein kinase 1 overexpression rescued the microRNA-199a-5p-induced suppression of proliferation, migration, and invasion of colorectal cancer cells. Furthermore, the overexpression of microRNA-199a-5p inhibited tumor growth and metastasis by inactivating the phosphoinositide 3-kinase/AKT and Janus kinase 1/signal transducing activator of transcription signaling pathways through downregulation of Rho-associated coiled coil-containing protein kinase 1. Altogether, microRNA-199a-5p/Rho-associated coiled coil-containing protein kinase 1 may be a potential therapeutic target for colorectal cancer therapy.

A microRNA cluster in the Fragile-X region expressed during spermatogenesis targets FMR1

Testis-expressed X-linked genes typically evolve rapidly. Here, we report on a testis-expressed X-linked microRNA (miRNA) cluster that despite rapid alterations in sequence has retained its position in the Fragile-X region of the X chromosome in placental mammals. Surprisingly, the miRNAs encoded by this cluster (Fx-mir) have a predilection for targeting the immediately adjacent gene, Fmr1, an unexpected finding given that miRNAs usually act in trans, not in cis Robust repression of Fmr1 is conferred by combinations of Fx-mir miRNAs induced in Sertoli cells (SCs) during postnatal development when they terminate proliferation. Physiological significance is suggested by the finding that FMRP, the protein product of Fmr1, is downregulated when Fx-mir miRNAs are induced, and that FMRP loss causes SC hyperproliferation and spermatogenic defects. Fx-mir miRNAs not only regulate the expression of FMRP, but also regulate the expression of eIF4E and CYFIP1, which together with FMRP form a translational regulatory complex. Our results support a model in which Fx-mir family members act cooperatively to regulate the translation of batteries of mRNAs in a developmentally regulated manner in SCs.

Engineering Allostery into Proteins

Our ability to engineer protein structure and function has grown dramatically over recent years. Perhaps the next level in protein design is to develop proteins whose function can be regulated in response to various stimuli, including ligand binding, pH changes, and light. Endeavors toward these goals have tested and expanded on our understanding of protein function and allosteric regulation. In this chapter, we provide examples from different methods for developing new allosterically regulated proteins. These methods range from whole insertion of regulatory domains into new host proteins, to covalent attachment of photoswitches to generate light-responsive proteins, and to targeted changes to specific amino acid residues, especially to residues identified to be important for relaying allosteric information across the protein framework. Many of the examples we discuss have already found practical use in medical and biotechnology applications.

MicroRNA-21 attenuates BDE-209-induced lipid accumulation in THP-1 macrophages by downregulating Toll-like receptor 4 expression

Growing evidence demonstrates a possible response of specific microRNA (miRNA) to environmental pollutant stimuli in multiple biological processes. We previously reported that a persistent organic pollutant, decabromodiphenyl ether (BDE-209), can enhance Toll-like receptor 4 (TLR4)-dependent lipid uptake in THP-1 macrophages; whether miRNAs are involved in this process remains unclear. In the present study, we investigated the levels of several miRNAs related to TLR4 signaling, including miRs-9, -21, -27b, -125b, -132, -146a, -147, -155, and -let-7e, in THP-1 macrophages after stimulation by BDE-209 and oxidized low-density lipoprotein. The results showed that the levels of miR-21 were significantly suppressed by BDE-209 at concentrations of 6.25, 12.5 and 25 μM, in a dose-dependent manner; whereas there was no significant changes for the other miRNAs investigated. Moreover, the suppression of miR-21 was accompanied by an upregulated TLR4 expression, at both mRNA and protein levels. Further analysis showed that the up-regulated TLR4 induced by BDE-209 was inhibited in macrophages transfected with miR-21 mimic; meanwhile opposite results were exhibited when an anti-miR-21 inhibitor was transfected to the macrophages. Additionally, transfection with miR-21 mimic effectively attenuated BDE-209-induced lipid accumulation in macrophages. Together, these data illustrate that miR-21 inhibits BDE-209-triggered lipid accumulation in macrophages through down-regulating TLR4 expression.

Oncogenic microRNA-411 promotes lung carcinogenesis by directly targeting suppressor genes SPRY4 and TXNIP

Lung cancer is one of the most common malignant diseases globally, composed of non-small cell lung cancer (NSCLC, 85%) and small cell lung cancer (SCLC, 15%). MicroRNAs (miRNAs) are single-stranded noncoding RNAs having important roles in lung cancer development. miR-411-5p/3p were reported to be increased significantly in human NSCLC tissues and cell lines. Moreover, miR-411-5p/3p overexpression could accelerate cell proliferation and migration, and impede cell apoptosis in NSCLC cell lines. Mechanically, SPRY4 is confirmed a direct target of miR-411-5p/3p. Furthermore, our findings showed that miR-411-5p/3p promoted lung tumor growth in vivo, decreased SPRY4 expression dramatically, and induced EGFR, AKT signaling activation, as well as epithelial–mesenchymal transition (EMT) simultaneously in tumor tissues. In addition, we showed that miR-411-5p also targeted tumor suppressor TXNIP, involved in regulating positively cell cycle progress in SPC-A1 cells rather than in H1299. Whether cell specificity of low TXNIP mRNA level in H1299 is responsible for the different response to cell cycle between H1299 and SPC-A1 would need further explorations. Collectively, these results suggest that miR-411-5p/3p are required for NSCLC development by suppressing SPRY4 and TXNIP; thus, the miR-411-SPRY4-AKT axis might act as a promising target for lung cancer therapy clinically.

MicroRNA-24-3p regulates Hodgkin's lymphoma cell proliferation, migration and invasion by targeting DEDD

Hodgkin's lymphoma (HL) is a common hematologic tumor, and the incidence is increasing. At present, it is considered that miRNAs are closely related to HL. Substantial attention has been paid to the effects of miRNA on the pathophysiological process of HL. This study was focused on the potential role of miR-24-3p in HL by targeting DEDD. The reverse transcription-quantitative PCR (RT-qPCR) results demonstrated that miR-24-3p expression was highly elevated and DEDD expression reduced inversely in HL tissues compared to adjacent tissues. According to the results of CKK-8 assays, miR-24-3p was able to accelerate HL cell proliferation. In addition, the results of the Transwell assays also indicated that miR-24-3p promoted the invasion and migration abilities of HL cells. Moreover, the results demonstrated that miR-24-3p inhibited DEDD expression. Hence, the present study revealed that miR-24-3p could accelerate HL development through inhibiting DEDD.

Antagonistic and cooperative AGO2-PUM interactions in regulating mRNAs

Approximately 1500 RNA-binding proteins (RBPs) profoundly impact mammalian cellular function by controlling distinct sets of transcripts, often using sequence-specific binding to 3′ untranslated regions (UTRs) to regulate mRNA stability and translation. Aside from their individual effects, higher-order combinatorial interactions between RBPs on specific mRNAs have been proposed to underpin the regulatory network. To assess the extent of such co-regulatory control, we took a global experimental approach followed by targeted validation to examine interactions between two well-characterized and highly conserved RBPs, Argonaute2 (AGO2) and Pumilio (PUM1 and PUM2). Transcriptome-wide changes in AGO2-mRNA binding upon PUM knockdown were quantified by CLIP-seq, and the presence of PUM binding on the same 3′UTR corresponded with cooperative and antagonistic effects on AGO2 occupancy. In addition, PUM binding sites that overlap with AGO2 showed differential, weakened binding profiles upon abrogation of AGO2 association, indicative of cooperative interactions. In luciferase reporter validation of candidate 3′UTR sites where AGO2 and PUM colocalized, three sites were identified to host antagonistic interactions, where PUM counteracts miRNA-guided repression. Interestingly, the binding sites for the two proteins are too far for potential antagonism due to steric hindrance, suggesting an alternate mechanism. Our data experimentally confirms the combinatorial regulatory model and indicates that the mostly repressive PUM proteins can change their behavior in a context-dependent manner. Overall, the approach underscores the importance of further elucidation of complex interactions between RBPs and their transcriptome-wide extent.

MicroRNA-21-Mediated Inhibition of Mast Cell Degranulation Involved in the Protective Effect of Berberine on 2,4-Dinitrofluorobenzene-Induced Allergic Contact Dermatitis in Rats via p38 Pathway

The study aimed to investigate the effect of berberine on allergic contact dermatitis (ACD) in rats and explore its underlying mechanisms. Firstly, ACD model was established by sensitizing and challenging with 2,4-dinitrofluorobenzene (DNFB) topically, and the rats were treated with berberine. Ear swelling was assessed, and cytokine, IgE, and histamine productions were measured. The ear biopsies were obtained for histology analysis. Additionally, rat peritoneal mast cells (RPMCs) were isolated for detection of microRNA-21 (miR-21) expression, mitogen-activated protein kinase (MAPK) signaling, and MC degranulation. Lastly, RPMCs were transfected with miR-21 mimic or miR-21 inhibitor to investigate the relationship between miR-21 and p38 pathway in MC. Our results showed that berberine significantly attenuated ear swelling in DNFB-induced ACD (ACD vs high dose of berberine 0.48 ± 0.03 vs. 0.33 ± 0.03 mm, P < 0.01), inhibited inflammatory cell infiltration (86 ± 5.16 vs. 58 ± 4.32 cells/mm², P < 0.01), reduced MC recruitment (61 ± 4.07 vs. 39 ± 3.42 mast cells/mm², P < 0.01), as well as decreased inflammatory cytokine, IgE, and histamine productions (all P < 0.05). Berberine treatment inhibited miR-21 expression, suppressed β-hexosaminidase and histamine release, and prevented p38 phosphorylation (all P < 0.05), which was abrogated by pretreatment with miR-21 overexpression. These findings indicate that miR-21-mediated inhibition of MC degranulation is involved in the anti-ACD effect of berberine via inhibiting p38 pathway, which provide a new insight into the immunopharmacological role of berberine and suggest its potential application for the treatment of allergic inflammation, such as ACD.

Long noncoding RNA H19 competitively binds miR-93-5p to regulate STAT3 expression in breast cancer

The long noncoding RNA H19 is overexpressed in many cancers and acts as an oncogene. Here, we explored the role of H19 in breast cancer cells, including the effect of H19 on proliferation, migration, and invasion of breast cancer cells. We also investigated the relation of H19 to microRNA miR-93-5p and signal transducers and activators of transcription 3 (STAT3), the target gene of miR-93-5p. Ectopic expression of H19 in MCF-7 cells and knockdown of H19 in MDA-MB-231 cells showed that overexpression of H19 promoted proliferation, migration, and invasion, whereas knockdown of H19 reduced proliferation, migration, and invasion in vitro. Dual-luciferase reporter assays and RNA-binding protein immunoprecipitation assays proved that H19 was a target of miR-93-5p. In addition, H19 antagonized the downregulation of miR-93-5p on its target STAT3 and antagonized miR-93-5p-mediated cell proliferation. Our study revealed a new network in the expression of STAT3 involving H19 and miR-93-5p, which may contribute to a better understanding of breast cancer pathogenesis and provide new insights into the treatment of this disease.

miR-27b-3p is Involved in Doxorubicin Resistance of Human Anaplastic Thyroid Cancer Cells via Targeting Peroxisome Proliferator-Activated Receptor Gamma

Chemotherapy is one of the most effective forms of cancer treatment. It has been widely used in the treatment of various malignant tumours. To investigate molecular mechanisms responsible for the chemoresistance of anaplastic thyroid cancer (ATC), we established the doxorubicin (Dox) resistance of human ATC SW1736 and 8305C cells and named them SW1736/Dox and 8305C/Dox, respectively. We evaluated the expression of various micro-RNAs (miRNAs) between control and Dox-resistant ATC cells and found that the expression of miR-27b-3p was significantly increased in Dox-resistant ATC cells. Targeted inhibition of miR-27b can increase the sensitivity of SW1736/Dox and 8305C/Dox cells. Bioinformatics analysis revealed that miR-27b can directly target peroxisome proliferator-activated receptor gamma (PPARγ) within the 3' untranslated region (UTR). This was proved by the results that miR-27b-3p down-regulated the protein and mRNA levels of PPARγ. While the mutant in the core binding sites of PPARγ abolished miR-27b-3p-induced down-regulation of luciferase activity. Over-expression of PPARγ can increase the Dox sensitivity of SW1736/Dox and 8305C/Dox cells. Basic fibroblast growth factor (bFGF) might be involved in miR-27b-3p/PPARγ-regulated Dox resistance of ATC cells. The activation of p65 nuclear factor-κB (NF-κB) regulated the up-regulation of miR-27b-3p in Dox-resistant ATC cells. Collectively, our data revealed that miR-27b-3p/PPARγ is involved in the Dox resistance of human ATC cells. It suggested that targeted inhibition of miR-27b-3p might be helpful to overcome the drug resistance of ATC cells.

Long non-coding RNA UCA1 modulates the glycolysis of cervical cancer cells by miR-493-5p/HK2

Long noncoding RNAs (lncRNAs) are associated with tumor development and progression. LncRNA UCA1 (UCA1) recently has been reported to take part in cancer cell proliferation. However, the expression and underlying molecular mechanism of UCA1 in cervical cancer cell glycolysis is unclear. This study aimed to investigate the role of UCA1 in cervical cancer. In order to explore the role of UCA1 in cervical cancer, first, the expression levels of UCA1 in cervical cancer tissues were measured, and the results showed that UCA1 levels were higher in cancer tissues compared to matched adjacent normal tissues. The inhibition of UCA1 expression suppressed human cervical cancer cell proliferation and glycolysis. Additionally, our experimental results indicated that UCA1 could directly bind to miR-493-5p and regulate miR-493-5p expression in an inverse manner. Namely, UCA1 could reverse the inhibitory effect of miR-493-5p on cervical cancer cells' proliferation and glycolysis. Moreover, we revealed that HK2 is a target gene of miR-493-5p through a Targetscan prediction. It was verified that miR-493-5p downregulated HK2 mRNA and protein levels using real time RT-PCR and Western blotting. In a summary, this study demonstrated that UCA1 functioned as an oncogene by UCA1/miR-493-5p/HK2 axis in cervical cancer.

RNAi-mediated antiviral immunity in mammals

RNA interference (RNAi) was discovered in plants where it functions as the main antiviral pathway and this antiviral role was subsequently extended to invertebrates. But it remained hotly debated whether RNAi fulfils a similar role in mammals that already have a potent innate immune system based on interferon and an elaborate adaptive immune system. On the one hand, mammalian cells do encode most of the RNAi machinery, but this could be used exclusively to control cellular gene expression via micro RNAs (miRNAs). But on the other hand, virus-derived small interfering RNAs, the hallmark of RNAi involvement, could not be readily detected upon virus infection of mammalian cells. However, recent studies have indicated that these signature molecules are generated in virus-infected embryonic cell types of mammals and that viruses actively suppress such responses by means of potent RNAi suppressor proteins. Thus, the tide seems to be changing in favor of RNAi as accessory antiviral defense mechanism in humans. Intriguingly, recent studies indicate that insects have also developed an additional innate immune system that collaborates with the RNAi response in the fight against invading viral pathogens. Thus, the presence of multiple antiviral response mechanisms seems standard outside the plant world and we will specifically discuss the interactions between these antiviral programs.

The role of αB-crystallin in skeletal and cardiac muscle tissues

All organisms and cells respond to various stress conditions such as environmental, metabolic, or pathophysiological stress by generally upregulating, among others, the expression and/or activation of a group of proteins called heat shock proteins (HSPs). Among the HSPs, special attention has been devoted to the mutations affecting the function of the αB-crystallin (HSPB5), a small heat shock protein (sHsp) playing a critical role in the modulation of several cellular processes related to survival and stress recovery, such as protein degradation, cytoskeletal stabilization, and apoptosis. Because of the emerging role in general health and disease conditions, the main objective of this mini-review is to provide a brief account on the role of HSPB5 in mammalian muscle physiopathology. Here, we report the current known state of the regulation and localization of HSPB5 in skeletal and cardiac tissue, making also a critical summary of all human HSPB5 mutations known to be strictly associated to specific skeletal and cardiac diseases, such as desmin-related myopathies (DRM), dilated (DCM) and restrictive (RCM) cardiomyopathy. Finally, pointing to putative strategies for HSPB5-based therapy to prevent or counteract these forms of human muscular disorders.

miR-224/miR-141 ratio as a novel diagnostic biomarker in renal cell carcinoma

Biomarkers to guide the clinical treatment of patients with renal cell carcinoma (RCC) are not yet routinely available. MicroRNAs (miRNAs) have been demonstrated to serve as biomarkers for a number of types of cancer. Based on a previous study by this group, we hypothesize that several highly differentially expressed miRNAs may serve as tissue and plasma biomarkers in patients with RCC. The expression levels of miR-210, miR-224 and miR-141 were analyzed in tissue samples from the same cohort of 78 patients with RCC, in paired pre- and post-operative plasma samples from 66 patients with clear cell RCC (ccRCC) and in 67 healthy controls by reverse transcription-quantitative polymerase chain reaction. Receiver operating characteristic (ROC) was used to evaluate the diagnostic accuracy associated with the expression of miR-210, miR-224 and miR-141. ROC curves revealed that the diagnostic accuracy (area under the curve) of tissue miR-210, miR-224, the ratio of miR-210/miR-141 (miR^210/141), miR-224/miR-141 (miR^224/141) and miR-210× miR-224/miR-141 (miR^210×224/141) in ccRCC was 0.8329, 0.8511, 0.9412, 0.9898 and 0.9771, respectively. Notably, miR^224/141 demonstrated the highest accuracy among these miRNAs for discriminating ccRCC tissues from normal tissues, with a sensitivity of 97.06% and a specificity of 98.53%. The expression levels of plasma miR-210 and miR-224 were significantly increased in patients compared with healthy control patients, and were reduced postoperatively (P<0.05). The diagnostic accuracy of plasma miR-210 and miR-224 were 0.6775 (89.55% sensitivity and 48.48% specificity) and 0.6056 (88.06% sensitivity and 40.91% specificity), respectively. The present study indicated that the tissue miR-224/miR-141 ratio is a potentially powerful tool for detecting ccRCC. However, plasma miR-210 and miR-224 may not be associated with diagnosis of ccRCC.

The effects of aberrant expression of LncRNA DGCR5/miR-873-5p/TUSC3 in lung cancer cell progression

Lung cancer is the most common cause of cancer‐related mortality worldwide, and nonsmall cell lung cancer (NSCLC) accounts for 80% of all pulmonary carcinomas. Recently, long noncoding RNAs (lncRNAs) have been paid attention for exploring treatment of various diseases. Upregulation of DiGeorge syndrome critical region gene 5 (DGCR5) predicts better lung squamous cell carcinoma prognosis; therefore, we explore the role of DGCR5 in lung cancer in our present study. Consecutive patients with LC were treated in our hospital between January 2015 and January 2016. qRT‐PCR demonstrated that DGCR5 was significantly lower in neoplastic tissues than in non‐neoplastic tissues. For in vitro experiments, cell growth, migration, and invasion were significantly lower in A549 cells transfected with pcDNA3.1‐DGCR5 than pcDNA3.1, which were verified by 5‐diphenyltetrazolium bromide (MTT) assay, scratch test, and transwell assay, respectively, with no significant induction on cell apoptosis that was demonstrated by flow cytometry (FCM) assay. Bioinformatics analysis predicted that 3’ untranslated region (UTR) of tumor suppressor candidate 3 (TUSC3, 49‐55 bp) and DGCR5 (801‐807 bp) shared a common hsa‐miR‐873‐5p binding site, and the direct interaction between DGCR5 and hsa‐miR‐873‐5p or hsa‐miR‐873‐5p and TUSC3 was verified by dual‐luciferase reporter assay. qRT‐PCR demonstrated that hsa‐miR‐873‐5p was dramatically higher and TUSC3 was significantly lower in neoplastic tissues than in non‐neoplastic tissues. DGCR5 decreased the protein level of TUSC3 by miR‐873‐5p which was demonstrated by Western blot and immunofluorescence. The role of DGCR5 in tumorigenesis in vivo was consistent with in vitro assays, Ki‐67‐positive cell number (exhibited by immunohistochemical staining), tumor size, and tumor weight of A549‐DGCR5 group were significantly lower in comparison with A549‐control group.

miR-409-3p suppresses the proliferation, invasion and migration of tongue squamous cell carcinoma via targeting RDX

The aim of the present study is to investigate the role of microRNA (miRNA/miR)-409-3p in the proliferation, invasion and migration of tongue squamous cell carcinoma (TSCC) cells via targeting radixin (RDX) gene. The expression of miR-409-3p was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in TSCC tissue and cell lines. The binding of miR-409-3p to RDX was investigated by performing a dual-luciferase reporter gene assay. Tca8113 cells were selected to transfect with miR-409-3p mimic/inhibitor, small interfering (si)-RDX, and miR-409-3p inhibitor + si-RDX, as well as negative control (NC) respectively. The proliferative, migratory and invasive abilities of transfected Tca8113 cells were investigated by cell-counting-kit-8, wound-healing and Transwell assays, respectively. Additionally, a tumor xenograft model was constructed to examine the effects of miR-409-3p on the tumor growth and lymphatic metastasis in nude mice. A significant downregulation was detected in miR-409-3p expression in TSCC tissues and cells (all P<0.05) compared with normal tongue mucosa tissues and cell line, which was associated with lymph node metastasis and tumor-node metastasis staging (both P<0.05). The results from the dual-luciferase reporter gene assay indicated that RDX is a potential target gene of miR-409-3p. Compared with the blank group, a marked reduction in RDX expression, cell proliferation, migration and invasion was detected in the miR-409-3p mimic group and si-RDX group (all P<0.05). Conversely, the reverse was observed in cells that were transfected with the miR-409-3p inhibitor. Furthermore, si-RDX is able to reverse the effect of miR-409-3p inhibitor on cell proliferation, invasion and migration (all P<0.05). The results form the tumor xenograft model of nude mice verified that miR-409-3p mimic is able to inhibit the growth of Tca8113 tumor cells and lymph node metastasis in nude mice. miR-409-3p may delay the proliferation of TSCC cells by inhibiting of RDX so as to decrease its migratory and invasive abilities. Therefore, miR-409-3p may be a potential target for the clinical treatment of TSCC.

LncRNA DGCR5 promotes lung adenocarcinoma (LUAD) progression via inhibiting hsa-mir-22-3p

Long non-coding RNAs (lncRNAs) serve critical roles in the pathogenesis of various cancers, including lung adenocarcinoma (LUAD). Herein, in this study, we aimed to investigate the biological and clinical significance of lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) in LUAD. It was observed that DGCR5 was upregulated in LUAD tissues and LUAD cell lines. Inhibition of DGCR5 can prevent LUAD progression via playing anti-apoptosis roles. Both mRNA expression and protein levels of BCL-2 were increased by DGCR5 downregulation while reversely BAX was increased. Additionally, a novel microRNA target of DGCR5, hsa-mir-22-3p was identified through bioinformatics search and confirmed by dual-luciferase reporter system. Gain and loss-of-function studies were performed to verify whether DGCR5 exerts its biological functions through regulating hsa-mir-22-3p in vitro. Overexpression of DGCR5 was able to reverse the tumor inhibitory effect of hsa-mir-22-3p mimics. Furthermore, in vivo tests tumor xenografts were established to detect the function of DGCR5 in LUAD tumorigenesis. Downregulated DGCR5 expression was greatly associated with smaller tumor size, implying a favorable prognosis of LUAD patients. Taken these together, DGCR5 could be considered as a prognostic biomarker and therapeutic target in LUAD diagnosis and treatment.

miR‑205‑5p/PTK7 axis is involved in the proliferation, migration and invasion of colorectal cancer cells

MicroRNAs (miRNAs) are small non‑coding RNAs, which are critical in a diverse range of biological processes, including development, differentiation, homeostasis, and in the formation of diseases by accelerating and/or inhibiting the translation of mRNAs. The present study aimed to examine the potential role of miRNA (miR)‑205‑5p in the developmental process of colorectal cancer (CRC) through protein‑tyrosine kinase 7 (PTK7). Initially, TargetScan was used to predict the miRNA target sites in the sequence of the PTK7 3'‑untranslated region. It was then found that the mRNA expression level of miR‑205‑5p was lower in CRC cells, determined using reverse transcription‑quantitative polymerase chain reaction analysis, and there was a negative correlation between miR‑205‑5p and PTK7 in CRC tissues. It was also found that miR‑205‑5p regulated the gene transcription of PTK7, determined using a luciferase reporter assay. The results of RT‑qPCR and western blot analyses in human colorectal cancer revealed that miR‑205‑5p suppressed the expression of PTK7. Finally, it was revealed that miR‑205‑5p restricted the proliferation ability of CRC cells through inhibiting PTK7, which was determined using colony forming and 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assays. miR‑205‑5p accelerated cell apoptosis through inhibiting PTK7, demonstrated using Annexin V‑FITC/propidium iodide staining. The results of a Transwell assay indicated that miR‑205‑5p inhibited the migration and invasion abilities of CRC cells through inhibiting PTK7. Therefore, miR‑205‑5p is involved in the proliferation, migration and invasion of CRC through inhibiting PTK7.

Dysregulation of microRNAs in autoimmune diseases: Pathogenesis, biomarkers and potential therapeutic targets

MicroRNAs (miRNAs) are small, single-stranded, endogenous non-coding RNAs that repress the expression of target genes via post-transcriptional mechanisms. Due to their broad regulatory effects, the precisely regulated, spatial-specific and temporal-specific expression of miRNAs is fundamentally important to various biological processes including the immune homeostasis and normal function of both innate and adaptive immune response. Aberrance of miRNAs is implicated in the development of various human diseases, especially cancers. Increasing evidence has revealed a dysregulated expression pattern of miRNAs in autoimmune diseases, among which many play key roles in the pathogenesis. In this review we summarize these findings on miRNA dysregulation implicated in autoimmune diseases, focusing on four representative systemic autoimmune diseases, i.e. systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and dermatomyositis. The causes of the dysregulation of miRNA expression in autoimmune diseases may include genetic and epigenetic variants, and various environmental factors. Further understanding of miRNA dysregulation and its mechanisms during the development of different autoimmune diseases holds enormous potential to bring about novel therapeutic targets or strategies for these complex human disorders, as well as novel circulating or exosomal miRNA biomarkers.

Seq-ing answers: uncovering the unexpected in global gene regulation

The development of techniques for measuring gene expression globally has greatly expanded our understanding of gene regulatory mechanisms in depth and scale. We can now quantify every intermediate and transition in the canonical pathway of gene expression—from DNA to mRNA to protein—genome-wide. Employing such measurements in parallel can produce rich datasets, but extracting the most information requires careful experimental design and analysis. Here, we argue for the value of genome-wide studies that measure multiple outputs of gene expression over many timepoints during the course of a natural developmental process. We discuss our findings from a highly parallel gene expression dataset of meiotic differentiation, and those of others, to illustrate how leveraging these features can provide new and surprising insight into fundamental mechanisms of gene regulation.

Long non-coding RNA HOXA-AS2 promotes proliferation and invasion of breast cancer by acting as a miR-520c-3p sponge

The long non-coding RNA (lncRNA) HOXA cluster antisense RNA2 (HOXA-AS2) has recently been shown to be dysregulated and involved in the progression of several cancers. However, the biological role and clinical significance of HOXA-AS2 in the carcinogenesis of breast cancer are still unclear. In the present study, we found that HOXA-AS2 was up-regulated in human breast cancer tissues and cell lines and associated with clinicopathological characteristics. Silencing of HOXA-AS2 inhibited the progression of breast cancer cells in vitro and in vivo. Furthermore, microarray profiling indicated that HOXA-AS2 serves as an endogenous sponge by directly binding to miR-520c-3p and down-regulating miR-520c-3p expression. We demonstrated that HOXA-AS2 controls the expression of miR-520c-3p target genes, TGFBR2 and RELA, in breast cancer cells. Therefore, our study may provide a better understanding of the pathogenesis of breast cancer and suggests that HOXA-AS2 may be a potential prognostic and therapeutic target in breast cancer.

MiRNA-142-3p increases radiosensitivity in human umbilical cord blood mononuclear cells by inhibiting the expression of CD133

This study is to explore the molecular regulation mechanism of CD133 which is associated with malignancy and poor prognosis of blood system diseases. CD133+HUCB-MNC (human umbilical cord blood mononuclear cells) and CD133-HUCB-MNC were isolated and amplificated from umbilical cord blood, and then were exposed to different doses of radiation and subjected to a clonogenic assay. CCK-8 kit was used to detect cell viability, Annexin V-FITC/PI cell apoptosis detection kit was used for the detection of apoptotic cells and the BrdU assay was performed by flow cytometry. The expression of protein was analyzed by western blots. The profile of miRNA expression in response to radiation was examined and validated by RT-PCR. miR-142-3p inhibited the expression of CD133 in umbilical cord blood mononuclear cells to increase radiosensitivity. CD133+HUCB-MNC cells were more radioresistant compared with CD133-HUCB-MNC cells. CD133+HUCB-MNC cells showed higher p-AKT and p-ERK levels after radiation. And miR-142-3p acted on 3'UTR of CD133 mRNA to inhibit CD133 expression. Moreover, miRNA-142-3p mimic increased radiosensitivity in CD133+HUCB-MNC cells. Our results elucidated a novel regulation pathway in hematopoietic stem cells and suggested a potential therapeutic approach for blood system diseases therapy.

Enhanced Chemotherapeutic Efficacy of Paclitaxel Nanoparticles Co-delivered with MicroRNA-7 by Inhibiting Paclitaxel-Induced EGFR/ERK pathway Activation for Ovarian Cancer Therapy

Chemotherapy-induced activation of cell survival pathways leads to drug resistance. MicroRNAs (miRNAs) post-transcriptionally regulate gene expression in many biological pathways. Paclitaxel (PTX) is one of the first-line chemotherapy drugs for ovarian cancer, and it induces the activation of the epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) pathway that leads to tumor cell proliferation, survival, invasion, and drug resistance. MicroRNA-7 (miR-7) has the ability to suppress the EGFR/ERK pathway. To sensitize chemotherapy, we developed monomethoxy(poly(ethylene glycol))-poly(d,l-lactide- co-glycolide)-poly(l-lysine) nanoparticles for the simultaneous co-delivery of PTX and miR-7. The resulting PTX/miR-7 nanoparticles (P/MNPs) protect miRNA from degradation, possess a sequential and controlled release of drugs, improve the transfection efficiency of miRNA, decrease the half-maximal inhibitory concentration of PTX, and increase the apoptosis of ovarian cancer cells. The chemotherapeutic efficacy of PTX is prominently enhanced in vitro and in vivo via the inhibition of PTX-induced EGFR/ERK pathway activation by miR-7. Our studies in P/MNPs reveal a novel paradigm for a dual-drug-delivery system of chemotherapeutics and gene therapy in treating cancers.

miR-152 is involved in the proliferation and metastasis of ovarian cancer through repression of ERBB3

MicroRNAs (miRNAs) participate in post-transcriptional regulation by targeting the 3' untranslated region of target genes that are involved in diverse biological processes. To the best of our knowledge, the association between miR‑152 and ERBB3 in ovarian cancer remains unclear. In the present study, a negative correlation between miR‑152 and ERBB3 in ovarian cancer was observed. The luciferase reporter gene assay results demonstrated that miR‑152 negatively regulated ERBB3 in SKOV3 and OVCAR3 ovarian cancer cells. Furthermore, our results revealed that miR‑152 suppressed the ability of ovarian cancer cell proliferation, migration and invasion, and promoted apoptosis through inhibiting ERBB3 in vitro. Therefore, in the present study, miR‑152 was found to be involved in the proliferation and metastasis of ovarian cancer cells through repression of ERBB3 expression. Therefore, miR‑152 may be a potential therapeutic target for the treatment of ovarian cancer.

A feedback loop consisting of RUNX2/LncRNA-PVT1/miR-455 is involved in the progression of colorectal cancer

Long non-coding RNAs (lncRNAs) have been shown to participate in cancer progression. In the present study, we explored the potential roles of lncRNA-PVT1 in the development process of colorectal cancer (CRC) via miR-455. We found that PVT1 is up-regulated in human CRC tissues compared to adjacent normal tissues. A functional study showed that the silencing of PVT1 expression by siRNAs inhibited cell proliferation, migration and invasion, whereas the overexpression of PVT1 accelerated cell proliferation, migration and invasion in vitro. A mechanistic study indicated PVT1 regulated the growth of CRC tumors by acting as a competing endogenous RNAs (ceRNA) and negatively regulated miR-455. Furthermore, we discovered that RUNX2, a functional transcription factor in CRC, up-regulated PVT1 expression. Therefore, our study suggested that the RUNX2/PVT1/miR-455 regulatory axis plays an important role in CRC tumorigenesis and may be a therapeutic target for the treatment of CRC.

The role of regulatory RNAs (miRNAs) in asthma

INTRODUCTION

Recently, a great deal of attention has been paid to the investigation of regulatory functions of microRNA. Currently, many different mechanisms involved in the pathogenesis of asthma are known, but the whole picture of pathogenesis has not yet been studied.

CONCLUSIONS

MicroRNAs play an important role in the regulation of many cellular processes. Undoubtedly, these regulatory molecules are involved in the pathogenesis of asthma, and therefore can be potential targets for treatment.

MicroRNA-14 regulates larval development time in Bombyx mori

MicroRNAs (miRNA) regulate multiple physiological processes including development and metamorphosis in insects. In the current study, we demonstrate that a conserved invertebrate miRNA-14 (miR-14) plays an important role in ecdysteroid regulated development in the silkworm Bombyx mori, a lepidopteran model insect. Ubiquitous transgenic overexpression of miR-14 using the GAL4/UAS system resulted in delayed silkworm larval development and smaller body size of larva and pupa with decrease in ecdysteriod titers. On the contrary, miR-14 disruption using the transgenic CRISPR/Cas9 system led to a precocious wandering stage with increase in ecdysteriod titers. We identified that the hormone receptor E75 (E75) and the ecdysone receptor isoform B (ECR-B), which both serve as essential mediators in the ecdysone signaling pathway, as putative target genes of miR-14 by in silico target prediction. Dual-luciferase reporter assays confirmed the binding of miR-14 to the 3'UTRs of E75 and ECR-B in a mammalian HEK293T cell line. Furthermore, transcription levels of E75 and ECR-B were significantly affected in both miR-14 overexpression and knockout transgenic animals. Taken together, our data suggested that the canonical invertebrate miR-14 is a general regulator in maintaining ecdysone homeostasis for normal development and metamorphosis in B. mori.

MicroRNA-30 inhibits antiapoptotic factor Mcl-1 in mouse and human hematopoietic cells after radiation exposure

We previously reported that microRNA-30 (miR-30) expression was initiated by radiation-induced proinflammatory factor IL-1β and NFkB activation in mouse and human hematopoietic cells. However, the downstream effectors of miR-30 and its specific role in radiation-induced cell death are not well understood. In the present study, we evaluated effects of radiation on miR-30 expression and activation of intrinsic apoptotic pathway Bcl-2 family factors in in vivo mouse and in vitro human hematopoietic cells. CD2F1 mice and human CD34+ cells were exposed to different doses of gamma-radiation. In addition to survival studies, mouse blood, bone marrow (BM) and spleen cells and human CD34+ cells were collected at 4 h, and 1, 3 and 4 days after irradiation to determine apoptotic and stress response signals. Our results showed that mouse serum miR-30, DNA damage marker γ-H2AX in BM, and Bim, Bax and Bak expression, cytochrome c release, and caspase-3 and -7 activation in BM and/or spleen cells were upregulated in a radiation dose-dependent manner. Antiapoptotic factor Mcl-1 was significantly downregulated, whereas Bcl-2 was less changed or unaltered in the irradiated mouse cells and human CD34+ cells. Furthermore, a putative miR-30 binding site was found in the 3′ UTR of Mcl-1 mRNA. miR-30 directly inhibits the expression of Mcl-1 through binding to its target sequence, which was demonstrated by a luciferase reporter assay, and the finding that Mcl-1 was uninhibited by irradiation in miR-30 knockdown CD34+ cells. Bcl-2 expression was not affected by miR-30. Our data suggest miR-30 plays a key role in radiation-induced apoptosis through directly targeting Mcl-1in hematopoietic cells.

MiR-221/222 promote epithelial-mesenchymal transition by targeting Notch3 in breast cancer cell lines

Basal-like breast cancer (BLBC) is an aggressive subtype with a strong tendency to metastasize. Due to the lack of effective chemotherapy, BLBC has a poor prognosis compared with luminal subtype breast cancer. MicroRNA-221 and -222 (miR-221/222) are overexpressed in BLBC and associate with metastasis as well as poor prognosis; however, the mechanisms by which miR-221/222 function as oncomiRs remain unknown. Here, we report that miR-221/222 expression is inversely correlated with Notch3 expression in breast cancer cell lines. Notch3 is known to be overexpressed in luminal breast cancer cells and inhibits epithelial to mesenchymal transition (EMT). We demonstrate that miR-221/222 target Notch3 by binding to its 3' untranslated region and suppressing protein translation. Ectopic expression of miR-221/222 significantly promotes EMT, whereas overexpression of Notch3 intracellular domain attenuates the oncogenic function of miR-221/222, suggesting that miR-221/222 exerts its oncogenic role by negatively regulating Notch3. Taken together, our results elucidated that miR-221/222 promote EMT via targeting Notch3 in breast cancer cell lines suggesting that miR-221/222 can serve as a potential therapeutic target in BLBC.

MicroRNA 26b promotes colorectal cancer metastasis by downregulating phosphatase and tensin homolog and wingless-type MMTV integration site family member 5A

Invasion and metastasis are crucially important factors in the survival of malignant tumors. Epithelial-mesenchymal transition (EMT) is an early step in metastatic progression and the presence of cancer stem cells is closely related to tumor survival, proliferation, metastasis, and recurrence. Herein we report that ectopic overexpression of microRNA 26b (miR-26b) in colorectal cancer (CRC) cell lines promoted EMT and stem cell-like phenotypes in vitro. Furthermore, miR-26b directly targeted and suppressed multiple tumor suppressors, including phosphatase and tensin homolog (PTEN) and wingless-type MMTV integration site family member 5A (WNT5A). Notably, miR-26b is markedly upregulated in tumor samples from patients with lymphatic metastases. These results indicate that miR-26b promotes CRC metastasis by downregulating PTEN and WNT5A, and may represent a therapeutic target for metastatic CRC.

LncRNA NEAT1 enhances the radio-resistance of cervical cancer via miR-193b-3p/CCND1 axis

LncRNAs have become a hot topic in various cancer-related researches. Radio-resistance is a great threat for cancer therapy. However, how lncRNAs affect the radio-resistance in cervical cancer is masked. As for our paper, it was discovered that NEAT1 was highly expressed in cervical cancer tissues and non-sensitive tissues as well as radio-resistant cell lines. And the overexpression of NEAT1 accelerated proliferation, while the knockdown of NEAT1 had the opposite result. The effect of NEAT1 on cell proliferation was dependent on the dose of ionizing radiation. And the silence of NEAT1 also caused cell cycle arrest in G0/G1 phase, and triggered more apoptosis, indicating the oncogenic role of NEAT1 in cervical cancer. Next, mechanistic assays affirmed that NEAT1 could function as a ceRNA to regulate cyclin D1 through sponging miR-193b-3p in cervical cancer. Rescue assays were employed to validate that miR-193b-3p and cyclin D1 could inhibit NEAT1-mediated suppressive effect on proliferation, and its stimulative effect on cell cycle arrest and apoptosis. In general, this article disclosed that NEAT1 could facilitate the radio-resistance of cervical cancer via competitively binding miR-193b-3p to up-regulate the expression of cyclin D1.

Hsa-miR-329 exerts tumor suppressor function through down-regulation of MET in non-small cell lung cancer

MicroRNAs (miRNAs) act as key regulators of multiple cancers. Hsa-miR-329 (miR-329) functions as a tumor suppressor in some malignancies. However, its role on lung cancer remains poorly understood. In this study, we investigated the role of miR-329 on the development of lung cancer. The results indicated that miR-329 was decreased in primary lung cancer tissues compared with matched adjacent normal lung tissues and very low levels were found in a non-small cell lung cancer (NSCLC) cell lines. Ectopic expression of miR-329 in lung cancer cell lines substantially repressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibiting cyclin D1, cyclin D2 and up-regulatiing p57(Kip2) and p21(WAF1/CIP1). In addition, miR-329 promoted NSCLC cell apoptosis, as indicated by up-regulation of key apoptosis gene cleaved caspase-3, and down-regulation of anti-apoptosis gene Bcl2. Moreover, miR-329 inhibited cellular migration and invasiveness through inhibiting matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene MET was revealed to be a putative target of miR-329, which was inversely correlated with miR-329 expression. Furthermore, down-regulation of MET by siRNA performed similar effects to over-expression of miR-329. Collectively, our results demonstrated that miR-329 played a pivotal role in lung cancer through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic MET.

miR-30e controls DNA damage-induced stress responses by modulating expression of the CDK inhibitor p21WAF1/CIP1 and caspase-3

MicroRNAs (miRNAs), a class of small non-coding RNAs that usually cause gene silencing by translational repression or degradation of mRNAs, are implicated in DNA damage-induced stress responses. To identify senescence-associated miRNAs, we performed microarray analyses using wild-type and p53-deficient HCT116 colon carcinoma cells that following gamma-irradiation (γIR) are driven into senescence and apoptosis, respectively. Several miRNAs including miR-30e were found upregulated in a p53-dependent manner specifically in senescent cells, but not in apoptotic cells. Overexpression of miR-30e in HCT116 cells not only inhibited γIR-, etoposide- or miR-34a-induced caspase-3-like DEVDase activities and cell death, but greatly accelerated and augmented their senescent phenotype. Consistently, procaspase-3 protein, but not mRNA decreased in the presence of miR-30e, whereas expression of the cyclin-dependent kinase inhibitor p21 increased both at the mRNA and protein level. Performing luciferase reporter gene assays, we identified the 3′-UTR of the caspase-3 mRNA as a direct miR-30e target. In contrast, although miR-30e was unable to bind to the p21 mRNA, it increased expression of a luciferase construct containing the p21 promoter, suggesting that the miR-30e-mediated upregulation of p21 occurs indirectly at the transcriptional level. Interestingly, despite suppressing procaspase-3 expression, miR-30e was unable to protect RKO colon carcinoma cells from DNA damage-induced death or to induce senescence, as miR-30e completely fails to upregulate p21 in these cells. These data suggest that miR-30e functions in a cell type-dependent manner as an important molecular switch for DNA damage-induced stress responses and may thus represent a target of therapeutic value.