Putative miRNA Targets Research Articles

Inhibiting miRNA Function by Antisense Oligonucleotides in Cultured Mammalian Cells.

Methods for transfecting antisense oligonucleotides (ASOs) into mammalian cells for suppression of miRNA function are described in this protocol. The effects of ASOs on the miRNA are evaluated by measuring the protein level of the putative miRNA target or the activity of a reporter bearing a 3' untranslated region (3' UTR) derived from the putative miRNA target.

Inhibiting miRNA Function by Antisense Oligonucleotides in Drosophila S2 Cells.

This protocol describes methods to transfect antisense oligonucleotides (ASOs) into Drosophila S2 cells for suppression of miRNA function. The effects of ASOs on the miRNA are evaluated by measuring the protein level of the putative miRNA target or the activity of a reporter bearing a 3' UTR derived from the putative miRNA target.

The effects of alternative splicing on miRNA binding sites in bladder cancer.

Eukaryotic organisms have developed a variety of mechanisms to regulate translation post-transcriptionally, including but not limited to the use of miRNA silencing in many species. One method of post-transcriptional regulation is through miRNAs that bind to the 3′ UTRs to regulate mRNA abundance and influence protein expression. Therefore, the diversity of mRNA 3′ UTRs mediating miRNA binding sites influence miRNA-mediated regulation. Alternative polyadenylation, by shortening mRNA isoforms, increases the diversity of 3′ UTRs; moreover, short mRNA isoforms elude miRNA-medicated repression. Because no current prediction methods for putative miRNA target sites consider whether or not 1) splicing-informed miRNA binding sites and/or 2) the use of 3′ UTRs provide higher resolution or functionality, we sought to identify not only the genome-wide impact of using exons in mRNA 3′ UTRs but also their functional connection to miRNA regulation and clinical outcomes in cancer. With a genome-wide expression of mRNA and miRNA quantified by 395 bladder cancer cases from The Cancer Genome Atlas (TCGA), we 1) demonstrate the diversity of 3′ UTRs affecting miRNA efficiency and 2) identify a set of genes clinically associated with mRNA expression in bladder cancer. Knowledge of 3′ UTR diversity will not only be a useful addition to current miRNA target prediction algorithms but also enhance the clinical utility of mRNA isoforms in the expression of mRNA in cancer. Thus, variability among cancer patient’s variability in molecular signatures based on these exon usage events in 3′ UTR along with miRNAs in bladder cancer may lead to better prognostic/treatment strategies for improved precision medicine.

Circadian clock genes are differentially modulated during the daily cycles and chronological age in the social honeybee (Apis mellifera)

The circadian clock is an advantageous adaptive system that enables organisms to predict and anticipate the daily environmental changes. The circadian rhythms are generated molecularly through the expression of clock genes, based on autoregulatory feedback loops. Honeybees are an excellent model to investigate how the circadian rhythms are modulated accordingly to the social context, behavioral plasticity, and task-related activities. Here, we show how the clock genes behave during the daily cycles in adult worker heads of Apis mellifera. Our results point to the clock genes period and cryptochrome as essential regulators of the circadian rhythms associated to the behavioral maturation in this social insect. We also identified putative miRNA-target and protein-protein interactions involving honeybee clock genes, indicating regulatory networks behind the adjustment of the molecular clock.

The use of high-throughput small RNA sequencing reveals differentially expressed microRNAs in response to aster yellows phytoplasma-infection in Vitis vinifera cv. 'Chardonnay'.

Phytoplasmas are cell wall-less plant pathogenic bacteria responsible for major crop losses throughout the world. In grapevine they cause grapevine yellows, a detrimental disease associated with a variety of symptoms. The high economic impact of this disease has sparked considerable interest among researchers to understand molecular mechanisms related to pathogenesis. Increasing evidence exist that a class of small non-coding endogenous RNAs, known as microRNAs (miRNAs), play an important role in post-transcriptional gene regulation during plant development and responses to biotic and abiotic stresses. Thus, we aimed to dissect complex high-throughput small RNA sequencing data for the genome-wide identification of known and novel differentially expressed miRNAs, using read libraries constructed from healthy and phytoplasma-infected Chardonnay leaf material. Furthermore, we utilised computational resources to predict putative miRNA targets to explore the involvement of possible pathogen response pathways. We identified multiple known miRNA sequence variants (isomiRs), likely generated through post-transcriptional modifications. Sequences of 13 known, canonical miRNAs were shown to be differentially expressed. A total of 175 novel miRNA precursor sequences, each derived from a unique genomic location, were predicted, of which 23 were differentially expressed. A homology search revealed that some of these novel miRNAs shared high sequence similarity with conserved miRNAs from other plant species, as well as known grapevine miRNAs. The relative expression of randomly selected known and novel miRNAs was determined with real-time RT-qPCR analysis, thereby validating the trend of expression seen in the normalised small RNA sequencing read count data. Among the putative miRNA targets, we identified genes involved in plant morphology, hormone signalling, nutrient homeostasis, as well as plant stress. Our results may assist in understanding the role that miRNA pathways play during plant pathogenesis, and may be crucial in understanding disease symptom development in aster yellows phytoplasma-infected grapevines.

MicroRNA dependent and independent deregulation of long non-coding RNAs by an oncogenic herpesvirus.

Kaposi’s sarcoma (KS) is a highly prevalent cancer in AIDS patients, especially in sub-Saharan Africa. Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of KS and other cancers like Primary Effusion Lymphoma (PEL). In KS and PEL, all tumors harbor latent KSHV episomes and express latency-associated viral proteins and microRNAs (miRNAs). The exact molecular mechanisms by which latent KSHV drives tumorigenesis are not completely understood. Recent developments have highlighted the importance of aberrant long non-coding RNA (lncRNA) expression in cancer. Deregulation of lncRNAs by miRNAs is a newly described phenomenon. We hypothesized that KSHV-encoded miRNAs deregulate human lncRNAs to drive tumorigenesis. We performed lncRNA expression profiling of endothelial cells infected with wt and miRNA-deleted KSHV and identified 126 lncRNAs as putative viral miRNA targets. Here we show that KSHV deregulates host lncRNAs in both a miRNA-dependent fashion by direct interaction and in a miRNA-independent fashion through latency-associated proteins. Several lncRNAs that were previously implicated in cancer, including MEG3, ANRIL and UCA1, are deregulated by KSHV. Our results also demonstrate that KSHV-mediated UCA1 deregulation contributes to increased proliferation and migration of endothelial cells.

Abstract 2536: miR-187-5p and miR-219a-1-3p: potential biomarkers associated with chemotherapeutic response and prognosis in ovarian cancer

Abstract Background: Epithelial ovarian cancer (EOC) is the fifth-most common cause of female cancer death and is associated with high recurrence and mortality despite recent advancements in therapeutic strategies. Chemoresistance remains the main cause of treatment failure in EOC patients. The aim of this study is to identify specific miRNA markers closely associated with the chemoresponse in EOC patients. Methods: We analyzed 374 serous ovarian cancer patients who receiving combination chemotherapy from The Cancer Genome Atlas (TCGA) and identified the most significantly altered miRNAs between different groups patients of chemotherapy response. We then used Kaplan-Meier and log-rank methods to analyze the relationship between these miRNAs and progression-free and overall survival in TCGA (n = 460) and Bagnoli (n = 130) datasets. In vitro study for response to chemotherapy agents were performed in human ovarian cancer cell lines and their transfectants. The biological relevance of putative miRNA targets was also analyzed using bioinformatics. Results: MiR-187-5p and miR-219a-1-3p were associated with better response to chemotherapy and longer progression-free and overall survival in two independent epithelial ovarian cancer patient cohorts (all p <0.05). These two miRNAs also sensitized ovarian cancer cells to chemotherapy, thus recapitulating the clinical observation. Conclusions: This study showed that miR-187-5p and miR-219a-1-3p could be useful biomarker for prediction of chemotherapy response and survival in serous ovarian cancers. MiR-187-5p and miR-219a-1-3p may be potential molecules in the treatment of EOC for sensitizing cancer cells to chemotherapy. Citation Format: Chia-Yen Huang, Hsien-Da Huang. miR-187-5p and miR-219a-1-3p: potential biomarkers associated with chemotherapeutic response and prognosis in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2536. doi:10.1158/1538-7445.AM2017-2536

The highly pathogenic H5N1 influenza A virus down-regulated several cellular MicroRNAs which target viral genome.

Higher and prolonged viral replication is critical for the increased pathogenesis of the highly pathogenic avian influenza (HPAI) subtype of H5N1 influenza A virus (IAV) over the lowly pathogenic H1N1 IAV strain. Recent studies highlighted the considerable roles of cellular miRNAs in host defence against viral infection. In this report, using a 3′UTR reporter system, we identified several putative miRNA target sites buried in the H5N1 virus genome. We found two miRNAs, miR‐584‐5p and miR‐1249, that matched with the PB2 binding sequence. Moreover, we showed that these miRNAs dramatically down‐regulated PB2 expression, and inhibited replication of H5N1 and H1N1 IAVs in A549 cells. Intriguingly, these miRNAs expression was differently regulated in A549 cells infected with the H5N1 and H1N1 viruses. Furthermore, transfection of miR‐1249 inhibitor enhanced the PB2 expression and promoted the replication of H5N1 and H1N1 IAVs. These results suggest that H5N1 virus may have evolved a mechanism to escape host‐mediated inhibition of viral replication through down‐regulation of cellular miRNAs, which target its viral genome.

Small RNA Sequencing Reveals Differential miRNA Expression in the Early Development of Broccoli (Brassica oleracea var. italica) Pollen.

Pollen development is an important and complex biological process in the sexual reproduction of flowering plants. Although the cytological characteristics of pollen development are well defined, the regulation of its early stages remains largely unknown. In the present study, miRNAs were explored in the early development of broccoli (Brassica oleracea var. italica) pollen. A total of 333 known miRNAs that originated from 235 miRNA families were detected. Fifty-five novel miRNA candidates were identified. Sixty of the 333 known miRNAs and 49 of the 55 predicted novel miRNAs exhibited significantly differential expression profiling in the three distinct developmental stages of broccoli pollen. Among these differentially expressed miRNAs, miRNAs that would be involved in the developmental phase transition from uninucleate microspores to binucleate pollen grains or from binucleate to trinucleate pollen grains were identified. miRNAs that showed significantly enriched expression in a specific early stage of broccoli pollen development were also observed. In addition, 552 targets for 127 known miRNAs and 69 targets for 40 predicted novel miRNAs were bioinformatically identified. Functional annotation and GO (Gene Ontology) analysis indicated that the putative miRNA targets showed significant enrichment in GO terms that were related to plant organ formation and morphogenesis. Some of enriched GO terms were detected for the targets directly involved in plant male reproduction development. These findings provided new insights into the functions of miRNA-mediated regulatory networks in broccoli pollen development.

Possible sexually dimorphic role of miRNA and other sncRNA in ASD brain

BackgroundAutism spectrum disorder (ASD) is sexually dimorphic in brain structure, genetics, and behaviors. In studies of brain tissue, the age of the population is clearly a factor in interpreting study outcome, yet sex is rarely considered. To begin to address this issue, we extend our previously published microarray analyses to examine expression of small noncoding RNAs (sncRNAs), including microRNAs (miRNAs), in ASD and in the control temporal cortex in males and females. Predicted miRNA targets were identified as well as the pathways they overpopulate.FindingsAfter considering age, sexual dimorphism in ASD sncRNA expression persists in the temporal cortex and in the patterning that distinguishes regions. Among the sexually dimorphic miRNAs are miR-219 and miR-338, which promote oligodendrocyte differentiation, miR-125, implicated in neuronal differentiation, and miR-488, implicated in anxiety. Putative miRNA targets are significantly over-represented in immune and nervous system pathways in both sexes, consistent with previous mRNA studies. Even for common pathways, the specific target mRNAs are often sexually dimorphic. For example, both male and female target genes significantly populate the Axonal Guidance Signaling pathway, yet less than a third of the targets are common to both sexes.ConclusionsOur findings of sexual dimorphism in sncRNA levels underscore the importance of considering sex, in addition to age, when interpreting molecular findings on ASD brain.

Microarray Expression Profile of Circular RNAs in Plasma from Primary Biliary Cholangitis Patients

Background/Aims: Circular RNAs (circRNAs) play a crucial role in the occurrence of several diseases, including autoimmune diseases. However, their role in primary biliary cholangitis (PBC) remains unclear. Here, we aimed to determine the circRNA expression profile in plasma from PBC patients and further explore the value of circRNA in diagnosing PBC. Methods: CircRNA microarrays were used to determine circRNA expression profiles in plasma samples from 6 PBC patients and 6 healthy controls. Statistical analyses identified differentially expressed circRNAs, and these circRNAs were verified by qRT-PCR in 29 PBC patients and 30 healthy controls. MicroRNA (miRNA) target prediction software identified putative miRNA response elements (MREs), which were used to construct a map of circRNA-miRNA interactions for the differentially expressed circRNAs. Results: Our results indicated that there were 18 up-regulated and 4 down-regulated circular RNAs in the plasma from PBC patients compared with that from healthy individuals. Among the differentially expressed circRNAs, hsa_circ_402458 (P=0.0033), hsa_circ_087631 and hsa_circ_406329 (P=0.0185) were up-regulated, and hsa_circ_407176 (P=0.0066) and hsa_circ_082319 were down-regulated in the PBC group versus the healthy group as demonstrated by qRT-PCR. In particular, hsa_circ_402458 was significantly higher in PBC patients not receiving UDCA treatment than in PBC patients receiving UDCA treatment (P=0.0338). The area under the receiver operating characteristic curve for hsa_circ_402458 for diagnosing PBC was 0.710 (P=0.005). For hsa_circ_402458, two putative miRNA targets, hsa-miR-522-3p and hsa-miR-943, were predicted. Conclusions: circRNA dysregulation may play a role in PBC pathogenesis, and hsa_circ_402458 shows promise as a candidate biomarker for PBC.

Tools for Sequence-Based miRNA Target Prediction: What to Choose?

MicroRNAs (miRNAs) are defined as small non-coding RNAs ~22 nt in length. They regulate gene expression at a post-transcriptional level through complementary base pairing with the target mRNA, leading to mRNA degradation and therefore blocking translation. In the last decade, the dysfunction of miRNAs has been related to the development and progression of many diseases. Currently, researchers need a method to identify precisely the miRNA targets, prior to applying experimental approaches that allow a better functional characterization of miRNAs in biological processes and can thus predict their effects. Computational prediction tools provide a rapid method to identify putative miRNA targets. However, since a large number of tools for the prediction of miRNA:mRNA interactions have been developed, all with different algorithms, the biological researcher sometimes does not know which is the best choice for his study and many times does not understand the bioinformatic basis of these tools. This review describes the biological fundamentals of these prediction tools, characterizes the main sequence-based algorithms, and offers some insights into their uses by biologists.

Integrated Data Set of microRNAs and mRNAs Involved in Severe Intrauterine Adhesion.

Adhesion tissue is formed following injury to the uterine basal layer. Currently, there is no effective treatment for severe intrauterine adhesion (IUA), which causes loss of reproductive function. Enhanced understanding of the molecular mechanisms driving severe IUA would be beneficial for the treatment. Differentially expressed microRNAs (miRNAs) and messenger RNAs (mRNAs) in severe IUA (n = 3) and normal (n = 3) endometrium were analyzed by high-throughput microarray analysis. Subsequently, the target genes of the differentially expressed miRNAs were predicted and found to overlap with the differentially expressed mRNAs. Gene Ontology and pathway analyses were performed for the intersecting genes. Three of the significantly dysregulated miRNAs and 4 of their target mRNAs were further assessed using quantitative real-time polymerase chain reaction (PCR) in 10 severe IUA and 10 normal endometrium samples. Microarray analysis indicated that 26 miRNAs and 1180 mRNAs were significantly different between the 2 groups. Of these, 16 miRNAs and 54 mRNAs overlapped with putative miRNA target genes and prediction of target gene. Real-time PCR revealed upregulation of hsa-miR-513a-5p and has-miR-135a-3p and downregulation of hsa-miR-543 and their corresponding target genes, plus downregulation of ADAM9 (a disintegrin-containing and metalloproteinases) and lysyl oxidase and upregulation of CDH2 (N-cadherin) and COL16A1 (collagen 16A1). Both CDH2 and COL16A1 were bioinformatically predicted and confirmed in vitro as target genes of miR-543. This study provides an integrated data set of the miRNA and mRNA profiles in severe IUA, showing involvement of many miRNAs and their target genes. Further analysis of these genes will help in understanding of the molecular mechanism of IUA formation.

Abstract 1913: Inhibition of S-Adenosylmethionine-dependent methyltransferase resists TGF-β1-induced EMT of pancreatic cancer via microRNA alterations

Abstract Identification of epigenetic reversal agents for use in combination chemotherapies for human pancreatic ductal adenocarcinomas remains an unmet clinical need. Pharmacological inhibitors of EZH2 are emerging as potential epigenetic reversal agents in various solid tumors and leukemia, however, the surprisingly small set of mRNA transcripts identified with EZH2 knockdown suggests novel mechanisms to govern their anti-tumorigenic effects. Here, we report 3-deazaneplanocin-A, an inhibitor of S-adenosyl-L-homocysteine hydrolase and EZH2 histone lysine-N-methyltransferase, to significantly reprogram the noncoding miRNA expression, including a subset of PDAC-downregulated miRNAs, to dampen TGF-β-induced EMT signals in pancreatic cancer. Particularly, we identify epigenetic silencing of miR-663a and -4787-5p in PDAC tissues and cell lines that are reactivated by 3-deazaneplanocin-A to directly target TGF-β1 for RNA interference. Lentiviral overexpression of miR-663a and -4787-5p partially phenocopied 3-deazaneplanocin-A's EMT resisting effects in pancreatic cancer cells, whereas locked nucleic acid antimiR-663a and -4787-5p mitigated them. In vivo, 3-deazaneplanocin-A, miR-663a and -4787-5p significantly reduced tumor burden and metastasis in an orthotopic mouse pancreatic tumor model with miR-663a displaying more potency than miR-4787-5p in curtailing TGF-β1 signaling pathway. These findings reveal tumor miRNA reprogramming as a novel approach for controlling TGF-β-induced EMT in human PDAC and uncover a list of putative miRNA targets that may guide further selection and development of synthetic histone methylation reversal agents for clinical use. Citation Format: Rajgopal Govindarajan, Hardik Modi. Inhibition of S-Adenosylmethionine-dependent methyltransferase resists TGF-β1-induced EMT of pancreatic cancer via microRNA alterations. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1913.

Ibrutinib downregulates a subset of miRNA leading to upregulation of tumor suppressors and inhibition of cell proliferation in chronic lymphocytic leukemia.

The lymph node (LN) is the site of chronic lymphocytic leukemia (CLL) cell activation and proliferation. Aberrant microRNA (miRNA) expression has been shown to have a role in CLL pathogenesis; however, a comparison of miRNA expression between CLL cells in the LN and the peripheral blood (PB) has previously not been reported. On the basis of the analysis of 17 paired LN and PB samples from CLL patients, we identify a panel of miRNAs that are increased in LN CLL cells correlating with an activation phenotype. When evaluated in CLL cells from 38 patients pre and post treatment with ibrutinib, a subset of these miRNAs (miR-22, miR-34a, miR-146b and miR-181b) was significantly decreased in response to ibrutinib. A concomitant increase in putative miRNA target transcripts (ARID1B, ARID2, ATM, CYLD, FOXP1, HDAC1, IBTK, PTEN and SMAD4) was also observed. Functional studies confirmed targets of ibrutinib-responsive miRNAs to include messenger RNA transcripts of multiple tumor suppressors. Knockdown of endogenous miR-34a and miR146b resulted in increased transcription of tumor suppressors and inhibition of cell proliferation. These findings demonstrate that ibrutinib downregulates the expression of a subset of miRNAs related to B-cell activation leading to increased expression of miRNA targets including tumor suppressors and a reduction in cell proliferation.

Association of MiR-26b mediated doxorubicin resistance signature with poor prognosis in epithelial ovarian cancer (EOC).

e17070Background: MicroRNAs (miRNA) have been established as key regulators of tumor gene expression as well as prime biomarker candidates for clinical phenotypes. We analyzed the regulatory structure of miRNAs and their colocalized gene targets in EOC tissue to construct a regulatory signature for clinical prognosis. Methods: FFPE blocks of primary EOC tumor tissue with > 80% tumor cells were selected for 20 patients (stage ≥ IIc) for whom follow up data was available. Expression levels of mRNA and miRNA were assayed separately. An integrated analysis was performed to identify miRNA/mRNA regulatory clusters. Gene set enrichment analysis (GSEA) was carried out on the coexpression of putative miRNA target genes, from the miRTarBase database, with their respective miRNAs, to identify enriched categories for each miRNA. MiRNAs with at least one significantly enriched category from the MSigDB C2 dataset at a false discovery rate of 0.05 were chosen. For each enriched category of each miRNA, a regulon was defi...

Alcohol Use During Pregnancy is Associated with Specific Alterations in MicroRNA Levels in Maternal Serum.

BackgroundGiven the challenges of confirming prenatal alcohol exposure (PAE) during pregnancy using currently established biomarkers of alcohol consumption, we examined whether serum microRNAs (miRNAs) may serve as stable biomarkers for PAE. Alterations in the levels of specific circulating miRNAs have been associated with various disease states and in animal models of fetal alcohol spectrum disorder.MethodsPregnant women in this prospective study were recruited from substance abuse and general maternity clinics affiliated with the University of New Mexico. Serum was collected at the time of admission for delivery from 14 subjects who reported ≥1 binge‐drinking episode or ≥3 drinks/wk during pregnancy and 16 subjects who reported abstinence during pregnancy and tested negative for 5 ethanol biomarkers. Total RNA was isolated from serum and used for microarray analysis.ResultsFalse discovery rate‐corrected analyses of covariance revealed that 55 miRNAs were significantly altered between the 2 groups. Hierarchical clustering using only the significantly altered miRNAs grouped samples into alcohol‐consuming and non‐alcohol‐consuming individuals. Discriminant analysis then identified miRs‐122*, ‐126, ‐216b, ‐221*, ‐3119, ‐3942‐5p, ‐4704‐3p, ‐4743, ‐514‐5p, and ‐602 as the top 10 discriminators between the 2 groups. Ingenuity Pathway Analysis of putative miRNA targets illustrated that miRNAs identified in this study are involved in biological pathways that mediate the effects of alcohol, such as brain‐derived neurotrophic factor, ERK1/2, and PI3K/AKT signaling.ConclusionsThis is the first report of alterations in serum miRNA expression that are associated with alcohol use during human pregnancy. These results suggest that serum miRNAs could be useful as biomarkers of alcohol exposure.

Expression profile of androgen-modulated microRNAs in the fetal murine lung.

BackgroundAndrogens are known to delay lung development. As a consequence, the incidence and morbidity of respiratory distress syndrome of the neonate are higher for male than for female premature infants. We previously reported that many genes were expressed with a sex difference in the mouse developing lung and that several genes were under the control of androgens in the male fetal lung. microRNAs are small non-coding RNAs known to negatively regulate the expression of specific genes. In this study, we examined whether murine miRNAs are under the control of androgens in the male developing lung.MethodsExpression profiling of microRNAs was performed by microarrays using RNA extracted from male fetal lungs isolated on gestational day (GD) 17.0 and GD 18.0 after daily injection of pregnant mice from GD 10.0 with the antiandrogen flutamide or vehicle only. To identify putative miRNA target genes, the data obtained here were combined with gene profiling data reported previously using the same RNA preparations. qPCR was used to confirm microarray data with fetal lungs from other litters than those used in microarrays.ResultsFlutamide induced downregulation and upregulation of several miRNAs on GD 17.0 and GD 18.0. Of the 43 mature miRNAs modulated by flutamide on GD 17.0, 60 % were downregulated, whereas this proportion was only of 34 % for the 35 mature miRNAs modulated on GD 18.0. For 29 and 26 flutamide-responsive miRNAs, we found a corresponding target inversely regulated by androgens on GD 17.0 and 18.0, respectively. The androgen-regulated target genes were involved in several biological processes (lipid metabolism, cell proliferation, and lung development) and molecular functions, mainly transcription factor binding.ConclusionsRegulation of male lung development involves several miRNAs that are under androgen modulation in vivo.Electronic supplementary materialThe online version of this article (doi:10.1186/s13293-016-0072-z) contains supplementary material, which is available to authorized users.

A novel framework for inferring condition-specific TF and miRNA co-regulation of protein–protein interactions

Recent studies have shown that transcription factors (TFs) and microRNAs (miRNAs), while independently regulate their downstream targets, collaborate with each other to regulate gene expression. However, their synergistic roles in protein–protein interactions (PPIs) remain mostly unknown. In this paper, we present a novel framework (called CoRePPI) for inferring TF and miRNA co-regulation of PPIs. Particularly, CoRePPI is aimed at discovering the co-regulation specific to a condition of interest, by using heterogeneous data, including miRNA and messenger RNA (mRNA) expression profiles, putative miRNA targets, TF targets and PPIs. CoRePPI firstly finds the network motifs indicating the co-regulation of PPIs by TFs and miRNAs in tumor and normal conditions separately. Then by identifying the differential motifs found in one condition but not in the other, it builds the networks consisting of TFs, miRNAs and their co-regulated PPIs specific to different conditions respectively. To validate CoRePPI, we apply it to the Pan-Cancer dataset which includes the expression profiles of 12 cancer types from TCGA. Through network topology analysis, we found that the tumor and normal CoRePPI networks are scale-free. Furthermore, the results of differential and intersected network analysis between the tumor and normal CoRePPI networks suggest that only a small fraction of the regulatory relationships between TFs and miRNAs are conserved in both conditions but they co-regulate different downstream PPIs in tumor and normal conditions; and in different conditions the majority of the regulatory relationships between TFs and miRNAs are different although they may regulate the same PPIs in their respective conditions. The CoRePPI sub-networks constructed for the three types of cancers (breast cancer, lung cancer and ovarian cancer) are all scale-free, and the intersection of these CoRePPI sub-networks can be utilized as the biomarker CoRePPI sub-network of the three types of cancers. The PPI enrichment analyses of the tumor and normal CoRePPI networks suggest that the co-regulating TFs and miRNAs are significantly associated with the specific biological processes, diseases and pathways. In addition, comparing with the two non-condition-specific approaches, the tumor CoRePPI network is found to have the most enriched cancer-related PPIs. Altogether, the results uncover the combined regulatory patterns of TFs and miRNAs on the PPIs, and may provide new insights for research in cancer-associated TFs and miRNAs.

Polymorphisms Falling Within Putative miRNA Target Sites in the 3'UTR Region of SIRT2 and DRD2 Genes Are Correlated With Human Longevity.

Many studies have suggested that individual differences in aging phenotypes may be associated to polymorphisms affecting gene regulation. As single-nucleotide polymorphisms (SNPs) in the 3'-untranslated regions (3'UTR) targeted by microRNAs (miRNAs) can alter the strength of miRNA binding (and, consequently, the regulation of target genes), we wondered whether these SNPs (known as miRSNPs) affect the individual chance to become long-lived. Thus, we estimated the effect of miRSNPs falling in the 3'-untranslated regions of 140 aging-related genes on the DNA/miRNA bond. The 24 miRSNPs with the highest difference of binding energy between the two alleles were then investigated for their association with longevity by case-control analysis. Two SNPs,SIRT2-rs45592833 G/T and DRD2-rs6276 A/G, provided a significant association with human longevity, also after correcting for multiple comparisons. For both SNPs, the minor allele was associated with a significantly decreased chance to became long-lived in an allele dose-dependent manner (p= 1.090 × 10(-6)and 1.964 × 10(-4)forSIRT2 and DRD2, respectively). The results indicate that the individual aging phenotype may be affected by the variability of specific miRNA targeted regions, as shown for SIRT2 and DRD2, and may suggest further studies to analyze the variability of gene expression regulation as a modulator of aging phenotypes.