Role Of microRNAs In Regulation Research Articles

Meet the First Authors.

Meet the First Authors.

MicroRNA-dependent regulation of Hox gene expression sculpts fine-grain morphological patterns in a Drosophila appendage.

ABSTRACTDisruptions of normal Hox gene expression can lead to severe morphological defects, revealing a link between the regulation of Hox expression and pattern formation. Here, we explore these links, focusing on the impact of microRNA regulation on the expression of the Drosophila Hox gene Ultrabithorax (Ubx) during haltere development. Through a combination of bioinformatic and transcriptomic analyses, we identify the miR-310/313 cluster (miR-310C) as a candidate regulator of Ubx. Several experiments confirm this. First, miR-310C and Ubx protein show complementary expression patterns in haltere imaginal discs; second, artificial activation of miR-310C expression in haltere discs leads to Ubx-like phenotypes. Third, expression of a fluorescent reporter bearing Ubx 3′UTR sequences is reduced when co-expressed with miR-310C. Fourth, deletion of miR-310C leads to Ubx upregulation and changes the array of mechanosensory sensilla at the base of the haltere. Fifth, an artificial increase of Ubx levels within the miR-310C expression domain phenocopies the mechanosensory defects observed in miR-310C mutants. We propose that miR-310C-mediated repression delimits Ubx fine-grain expression, contributing to the sculpting of complex morphologies in the Drosophila haltere with implications for flight control. Our work reveals a novel role of microRNA regulation in the control of Hox gene expression with impact on morphology.

MiR-31 and miR-143 affect steroid hormone synthesis and inhibit cell apoptosis in bovine granulosa cells through FSHR

The regulatory role of microRNAs (miRNAs) has been explored in ovarian cells, and the effects of miRNAs on gonadal development, apoptosis, ovulation, and steroid production have been reported. In this study, we analyzed the effects of follicle stimulating hormone (FSH) on miR-31 and miR-143 expression levels in bovine granulosa cells (GCs). Our results demonstrated that the FSH receptor (FSHR) is a common target gene of miR-31 and miR-143 in bovine GCs. We further analyzed the roles of miR-31 and miR-143 in bovine GCs by transfecting miR-31 and miR-143 mimics and inhibitors. The Western blot and RT-PCR results showed that miR-31 and miR-143 reduced the mRNA and protein expression levels of FSHR. Moreover, miR-31 overexpression decreased the secretion of progesterone (P4), and miR-143 overexpression decreased both the synthesis of P4 and the secretion of estrogen (E2). In contrast, miR-31 inhibition increased the secretion of progesterone (P4), and miR-143 inhibition increased both the synthesis of P4 and the secretion of E2. Finally, we analyzed the possible effects of miR-31 and miR-143 on bovine GC apoptosis. The results showed that transfection with miR-31 and miR-143 mimics promoted GC apoptosis and that miR-143 and miR-31 inhibition reduced the rate of apoptosis in bovine GCs. Taken together, our results indicate that miR-31 and miR-143 decrease steroid hormone synthesis and inhibit bovine GC apoptosis by targeting FSHR.

MicroRNA-7450 regulates non-thermal plasma-induced chicken Sertoli cell apoptosis via adenosine monophosphate-activated protein kinase activation

Non-thermal plasma treatment is an emerging innovative technique with a wide range of biological applications. This study was conducted to investigate the effect of a non-thermal dielectric barrier discharge plasma technique on immature chicken Sertoli cell (SC) viability and the regulatory role of microRNA (miR)-7450. Results showed that plasma treatment increased SC apoptosis in a time- and dose-dependent manner. Plasma-induced SC apoptosis possibly resulted from the excess production of reactive oxygen species via the suppression of antioxidant defense systems and decreased cellular energy metabolism through the inhibition of adenosine triphosphate (ATP) release and respiratory enzyme activity in the mitochondria. In addition, plasma treatment downregulated miR-7450 expression and activated adenosine monophosphate-activated protein kinase α (AMPKα), which further inhibited mammalian target of rapamycin (mTOR) phosphorylation in SCs. A single-stranded synthetic miR-7450 antagomir disrupted mitochondrial membrane potential and decreased ATP level and mTOR phosphorylation by targeting the activation of AMPKα, which resulted in significant increases in SC lethality. A double-stranded synthetic miR-7450 agomir produced opposite effects on these parameters and ameliorated plasma-mediated apoptotic effects on SCs. Our findings suggest that miR-7450 is involved in the regulation of plasma-induced SC apoptosis through the activation of AMPKα and the further inhibition of mTOR signaling pathway.

Deciphering the Role of microRNAs in Regulation of Immune Surveillance, Self-Tolerance and Allograft Transplant Outcome.

MicroRNAs are small non-coding RNAs that can modulate gene expression at posttranscriptional level, and they participate in almost all important biological processes. Immune system is elaborately regulated to maintain the equilibrium between immunity and tolerance. Recent studies have revealed significant functions of microRNAs in the maintenance of immune homeostasis using both cell and transgenic mouse models. In collaboration with various transcriptional factors and cytokines, microRNAs constitute an effective and flexible regulatory network governing the development and activation of immune cells; as well as maintenance of immune tolerance. In this review, microRNAs involved in T cell development, proliferation, and lineage differentiation will be summarized. Based on current knowledge, the function of microRNAs in establishing and maintaining immune tolerance will also be discussed in relation to determining the outcome of allograft transplantation.

The transcription factor T-bet is regulated by microRNA-155 in murine anti-viral CD8+ T cells via SHIP-1.

Abstract MicroRNAs (miRNAs) are small, single-stranded non-coding RNAs that play essential roles in regulating key cellular processes, and are highly conserved across species. However, the regulatory role of microRNAs in generating effective CD8+ T cell (CTL) responses to viral infection and tumors is only now being elucidated. Microarray miRNA expression profiling identified unique expression patterns of miRNAs in naïve and effector anti-viral CTL. In particular, microRNA-155 was significantly upregulated in effector CTL. Previously, we have demonstrated that miR-155 is essential to CD8+ T cell responses to viral and intracellular bacterial infections. In the present study, we show that miR-155 overexpression in CTL augments anti-viral effector CTL and skews memory CD8+ T cells towards an effector memory phenotype. MiR-155 overexpression resulted in enhanced T-bet expression, which is known to be required for effector CTL and to promote effector memory cell formation. Importantly, we show that the proliferative effect of miR-155 on CD8+ T cells is mediated by T-bet. In CTL, T-bet levels were controlled in vivo by miR-155 via SH2 (Src homology 2)-containing inositol phosphatase-1 (SHIP-1), a known direct target of miR-155. Our studies have revealed an important and unexpected link between miR-155, T-bet transcription factor and SHIP-1 in the context of CTL responses to an in vivo viral infection.

Regulatory role of microRNA in mesenteric lymph nodes after Salmonella Typhimurium infection

Salmonellosis is a gastrointestinal disease caused by non-typhoidal Salmonella serovars such as Salmonella Typhimurium. This pathology is a zoonosis, and food animals with subclinical infection constitute a vast reservoir for disease. After intestinal colonization, Salmonella Typhimurium reaches mesenteric lymph nodes (MLN), where infection is controlled avoiding systemic spread. Although the molecular basis of this infection has been extensively studied, little is known about how microRNA (miRNA) regulate the expression of proteins involved in the Salmonella-host interaction. Using small RNA-seq, we examined expression profiles of MLN 2 days after infection with Salmonella Typhimurium, and we found 110 dysregulated miRNA. Among them, we found upregulated miR-21, miR-155, miR-150, and miR-221, as well as downregulated miR-143 and miR-125, all of them previously linked to other bacterial infections. Integration with proteomic data revealed 30 miRNA potentially regulating the expression of 15 proteins involved in biological functions such as cell death and survival, inflammatory response and antigenic presentation. The inflammatory response was found increased via upregulation of miRNA such as miR-21 and miR-155. Downregulation of miR-125a/b, miR-148 and miR-1 were identified as potential regulators of MHC-class I components PSMB8, HSP90B1 and PDIA3, respectively. Furthermore, we confirmed that miR-125a is a direct target of immunoproteasome component PSMB8. Since we also found miR-130 downregulation, which is associated with upregulation of HSPA8, we suggest induction of both MHC-I and MHC-II antigen presentation pathways. In conclusion, our study identifies miRNA that could regulate critical networks for antigenic presentation, inflammatory response and cytoskeletal rearrangements.

Regulatory Role of MicroRNAs in Muscle Atrophy during Exercise Intervention.

Skeletal muscle comprising approximately 40% of body weight is highly important for locomotion and metabolic homeostasis. The growth and regeneration of skeletal muscle are highly organized processes; thus, it is not surprising to reveal certain complexity during these regulatory processes. Recently, a large number of evidence indicate that microRNAs can result in obvious impacts on growth, regeneration and metabolism of skeletal muscle. In this review, recent research achievements of microRNAs in regulating myogenesis, atrophy and aging during exercise intervention are discussed, which will provide the guidance for developing potential applications of microRNAs in health promotion and rehabilitation of sports injuries.

The Role of MicroRNA in Regulation of Signaling Pathways in Gliomas

Gliomas are invasive brain tumors characterized by high rates of recurrence and mortality. Glioblastoma multiforme (GBM) is the most aggressive form of glioma with nearly 100% rate of recurrence and unfavorable prognosis in patients. MicroRNAs (miR) are a class of wide-spread short noncoding RNAs that inhibit translation via binding to the mRNA of target genes. The aim of this review is to analyze studies and experimental results on changes in the expression profiles of microRNA which are characteristic for gliomas/ glioblastomas and targeted to components of signaling pathways Hedgehog, Notch, Wnt, EGFR, TGFβ, and HIF1α, aberrantly regulated in the gliomas. Special attention has been paid to the links of microRNA to the targets of 2-hydroxyglutarate, the product of mutant isocitrate dehydrogenase (R132H IDH1), mutational changes of which are specific for the pathogenesis of gliomas. Detection of certain types of microRNA in tissues and blood serum can be used for diagnostics and prediction, including responsiveness of individual patients to therapy, and development of new therapeutic strategies.

Regulatory roles of micro-RNAs in T cell autoimmunity

ABSTRACTMicroRNAs (miRNAs) are short conserved non-coding RNA molecules that have recently emerged as post-transcriptional gene expression regulators. miRNAs degrade or repress target mRNAs by targeting the 3ʹ UTR region. miRNA-mediated gene regulation is crucial for regular biological processes such as immune cell lineage commitment, differentiation, maturation, and maintenance of immune homeostasis and regular function. Changes in miRNA expression patterns have been recorded in a wide range of human diseases, including autoimmunity, especially in T cell-related autoimmunity. This review discusses recent progress in miRNA-mediated regulation of T cell-related autoimmunity. Specifically, we discuss the modality of T cell-related autoimmunity regulation by miRNAs through affecting molecular and biological processes.

MicroRNA expression in the neural retina: Focus on Müller glia.

The neural retina hosts a unique specialized type of macroglial cell that not only preserves retinal homeostasis, function, and integrity but also may serve as a source of new neurons during regenerative processes: the Müller cell. Precise microRNA-driven mechanisms of gene regulation impel and direct the processes of Müller glia lineage acquisition from retinal progenitors during development, the triggering of their response to retinal degeneration and, in some cases, Müller cell reprogramming and regenerative events. In this review we survey the recent reports describing, through functional assays, the regulatory role of microRNAs in Müller cell physiology, differentiation potential, and retinal pathology. We discuss also the evidence based on expression analysis that points out the relevance of a Müller glia-specific microRNA signature that would orchestrate these processes.

Genome-wide identification of cucumber green mottle mosaic virus-responsive microRNAs in watermelon.

Cucumber green mottle mosaic virus (CGMMV) is a damaging pathogen that attacks crop plants belonging to the family Cucurbitaceae. Little is known about the regulatory role of microRNAs (miRNAs) in response to CGMMV infection. To identify CGMMV-responsive miRNAs, two sRNA libraries from mock-inoculated and CGMMV-infected watermelon leaves were constructed and sequenced using Solexa sequencing technology. In total, 471 previously known and 1,809 novel miRNAs were obtained, of which 377 known and 246 novel miRNAs were found to be differentially expressed during CGMMV infection. The target genes for the CGMMV-responsive known miRNAs are active in diverse biological processes, including cell wall modulation, plant hormone signaling, defense-related protein induction, primary and secondary metabolism, regulation of virus replication, and intracellular transport. The expression patterns of some CGMMV-responsive miRNAs and their corresponding targets were confirmed by RT-qPCR. One target gene for miR156a-5p was verified by 5'-RNA-ligase-mediated rapid amplification of cDNA ends (5'-RLM-RACE) analysis. The results of this study provide further insights into the miRNA-mediated regulatory network involved in the response to viral infection in watermelon and other cucurbit crops.

Micro RNAs and DNA methylation are regulatory players in human cells with altered X chromosome to autosome balance

The gene balance hypothesis predicts that an imbalance in the dosage sensitive genes affects the cascade of gene networks that may influence the fitness of individuals. The phenotypes associated with chromosomal aneuploidies demonstrate the importance of gene dosage balance. We have employed untransformed human fibroblast cells with different number of X chromosomes to assess the expression of miRNAs and autosomal genes in addition to the DNA methylation status. High throughput NGS analysis using illumina Next seq500 has detected several autosomal as well as X linked miRNAs as differentially expressed in X monosomy and trisomy cells. Two of these miRNAs (hsa-miR-125a-5p and 335-5p) are likely to be involved in regulation of the autosomal gene expression. Additionally, our data demonstrates altered expression and DNA methylation signatures of autosomal genes in X monosomy and trisomy cells. In addition to miRNAs, expression of DNMT1 which is an important epigenetic player involved in many processes including cancer, is seen to be altered. Overall, present study provides a proof for regulatory roles of micro RNAs and DNA methylation in human X aneuploidy cells opening up possible new ways for designing therapeutic strategies.

The miRNAome of Catharanthus roseus: identification, expression analysis, and potential roles of microRNAs in regulation of terpenoid indole alkaloid biosynthesis

MicroRNAs (miRNAs) regulate numerous crucial biological processes in plants. However, information is limited on their involvement in the biosynthesis of specialized metabolites in plants, including Catharanthus roseus that produces a number of pharmaceutically valuable, bioactive terpenoid indole alkaloids (TIAs). Using small RNA-sequencing, we identified 181 conserved and 173 novel miRNAs (cro-miRNAs) in C. roseus seedlings. Genome-wide expression analysis revealed that a set of cro-miRNAs are differentially regulated in response to methyl jasmonate (MeJA). In silico target prediction identified 519 potential cro-miRNA targets that include several auxin response factors (ARFs). The presence of cleaved transcripts of miRNA-targeted ARFs in C. roseus cells was confirmed by Poly(A) Polymerase-Mediated Rapid Amplification of cDNA Ends (PPM-RACE). We showed that auxin (indole acetic acid, IAA) repressed the expression of key TIA pathway genes in C. roseus seedlings. Moreover, we demonstrated that a miRNA-regulated ARF, CrARF16, binds to the promoters of key TIA pathway genes and repress their expression. The C. roseus miRNAome reported here provides a comprehensive account of the cro-miRNA populations, as well as their abundance and expression profiles in response to MeJA. In addition, our findings underscore the importance of miRNAs in posttranscriptional control of the biosynthesis of specialized metabolites.

CagA-positive and CagA-negative Helicobacter pylori strains differentially affect the expression of micro RNAs 21, 92a, 155 and 663 in human umbilical vein endothelial cells.

Given that the basic mechanism of the effect of Helicobacter (H.) pylori in the induction of atherosclerosis remains unknown and regarding the regulatory role of micro RNAs (miRNAs) in endothelial cell (EC) functions, we aimed to investigate the effect of H. pylori on the expression of miRNAs involved in atherosclerosis (atheromiRs) and their correlation with apoptosis in human umbilical vein EC (HUVEC). HUVECs were treated with different cytotoxin associated gene A (CagA) positive and negative H. pylori derived products, then the levels of apoptosis and miR-21, 92a, 155 and 663 were measured using flowcytometry and real time-PCR methods, respectively. Although, comparing induced apoptosis and necrosis in HUVECs revealed that water extract of CagA+ H. pylori (HpWE) was more potent than CagA- one and H. pylori lipopolysacharide (Hp-LPS), no significant difference was observed between LPS extracted from CagA+ and CagA- strains. Besides, CagA+ HpWE significantly increased the levels of anti-apoptotic miR-21, and inflammatory miRNAs 155 and 663 but not miR-92a. A positive correlation was observed between apoptosis and necrosis and miR-155 as well as the expressions of miR-21 with miR-155 (P=0.024) and miR-663 (P=0.0001). As H. pylori products differentially influenced phenotypic and epigenetic changes in ECs pictured in apoptosis and in the expression of atheromiRs, we suggest that the presence of CagA molecule accompanied by these atheromiRs may act as beneficial biomarkers predicting ECs apoptosis as a sign of plaque rupture.

Emerging role of microRNAs in regulation of nicotine dependence: A Caenorhabditis elegans model

Emerging role of microRNAs in regulation of nicotine dependence: A Caenorhabditis elegans model

The Regulatory Roles of MicroRNA in Effects of 2,2'4,4'-Tetrabromodiphenyl Ether (BDE47) on the Transcriptome of Zebrafish Larvae.

The developmental neurotoxicity caused by environmental pollutants has received great concern; however, there were still barely known about the underlying toxic mechanisms, especially the influence of varieties of regulatory factors such as microRNA (miRNA). A representative flame retardant, 2,2′,4,4′-tetrabromodiphenyl ether (BDE47), was found to disrupt zebrafish development in visual perception and bone formation in previous study, thus here we investigated its effects on miRNA expression profiling of 6 days post fertilization (dpf) zebrafish larvae by deep sequencing. To overcome the shortage of zebrafish miRNA annotation, multiple data processing approaches, especially constructed network based on the interactions between miRNAs and enrichment terms, were adopted and helped us acquire several validated zebrafish miRNAs and two novel miRNAs in BDE47-induced effects, and identify corresponding biological processes of the miRNAs. Among them, miR-735 was supposed to play essential roles in larval sensory development according to analysis results. Our study also provided an effective strategy for analyzing biological effects on non-mammalian miRNAs with limited basic information.

Regulatory role of microRNA on inflammatory responses of diabetic retinopathy.

Regulatory role of microRNA on inflammatory responses of diabetic retinopathy.

MicroRNA-Related Polymorphisms in PI3K/Akt/mTOR Pathway Genes Are Predictive of Limited-Disease Small Cell Lung Cancer Treatment Outcomes

The phosphoinositide-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in cancer progression and treatment, including that of small cell lung cancer (SCLC), a disease with traditionally poor prognosis. Given the regulatory role of microRNA (miRNA) in gene expression, we examined the association of single nucleotide polymorphisms (SNPs) at miRNA-binding sites of genes in the mTOR pathway with the prognosis of patients with limited-disease SCLC. A retrospective study was conducted of 146 patients with limited-disease SCLC treated with chemoradiotherapy. Nine SNPs of six mTOR pathway genes were genotyped using blood samples. Cox proportional hazard regression modeling and recursive partitioning analysis were performed to identify SNPs significantly associated with overall survival. Three SNPs, MTOR: rs2536 (T>C), PIK3R1: rs3756668 (A>G), and PIK3R1: rs12755 (A>C), were associated with longer overall survival. Recursive partitioning analysis based on unfavorable genotype combinations of the rs2536 and rs3756668 SNPs classified patients into three risk subgroups and was internally validated with 1000 bootstrap samples. These findings suggest that miRNA-related polymorphisms in the PI3K/Akt/mTOR pathway may be valuable biomarkers to complement clinicopathological variables in predicting prognosis of limited-disease SCLC and to facilitate selection of patients likely to benefit from chemoradiotherapy.

MicroRNAs 33, 122, and 208: a potential novel targets in the treatment of obesity, diabetes, and heart-related diseases.

Despite decades of research, obesity and diabetes remain major health problems in the USA and worldwide. Among the many complications associated with diabetes is an increased risk of cardiovascular diseases, including myocardial infarction and heart failure. Recently, microRNAs have emerged as important players in heart disease and energy regulation. However, little work has investigated the role of microRNAs in cardiac energy regulation. Both human and animal studies have reported a significant increase in circulating free fatty acids and triacylglycerol, increased cardiac reliance on fatty acid oxidation, and subsequent decrease in glucose oxidation which all contributes to insulin resistance and lipotoxicity seen in obesity and diabetes. Importantly, MED13 was initially identified as a negative regulator of lipid accumulation in Drosophilia. Various metabolic genes were downregulated in MED13 transgenic heart, including sterol regulatory element-binding protein. Moreover, miR-33 and miR-122 have recently revealed as key regulators of lipid metabolism. In this review, we will focus on the role of microRNAs in regulation of cardiac and total body energy metabolism. We will also discuss the pharmacological and non-pharmacological interventions that target microRNAs for the treatment of obesity and diabetes.