Project description:Clear cell renal cell carcinomas (ccRCC) are characterized by arm-wide chromosomal alterations. Loss at 14q is associated with disease aggressiveness in ccRCC, which responds poorly to chemotherapeutics. The 14q locus contains one of the largest miRNA clusters in the human genome; however, little is known about the contribution of these miRNAs to ccRCC pathogenesis. In this regard, we investigated the expression pattern of selected miRNAs at the 14q32 locus in TCGA kidney tumors and in ccRCC cell lines. We validated that the miRNA cluster is downregulated in ccRCC (and cell lines) as well as in papillary kidney tumors relative to normal kidney tissues and primary renal proximal tubule epithelial (RPTEC) cells. We demonstrated that agents modulating expression of DNMT1 (e.g., 5-Aza-deoxycytidine) could modulate miRNA expression in ccRCC cell lines. Lysophosphatidic acid (LPA, a Lysophospholipid mediator elevated in ccRCC) not only increased labile iron content but also modulated expression of 14q32 miRNAs. Through an overexpression approach targeting a subset of 14q32 miRNAs (specifically at subcluster A: miR-431, miR-432, miR-127, and miR-433) in 769-P cells, we uncovered changes in cellular viability and claudin-1, a tight junction marker. A global proteomic approach was implemented using these miRNA overexpressing cell lines which uncovered ATXN2 as a highly downregulated target, which has a role in chronic kidney disease pathogenesis. Collectively, these findings support a contribution of miRNAs at 14q32 in ccRCC pathogenesis.
Project description:Transmissible gastroenteritis virus (TGEV) is a member of Coronaviridae family. Our previous research showed that TGEV infection could induce mitochondrial dysfunction and up-regulat miR-222 level. Therefore, we presumed that miR-222 might be implicated in regulating mitochondrial dysfunction induced by TGEV infection. To verify the hypothesis, the effect of miR-222 on mitochondrial dysfunction was detected and showed that miR-222 attenuated TGEV-induced mitochondrial dysfunction. To investigate the underlying molecular mechanism of miR-222 in TGEV-induced mitochondrial dysfunction, a quantitative proteomic analysis of PK-15 cells that were transfected with miR-222 mimics and infected with TGEV was performed. In total, 4151 proteins were quantified and 100 differentially expressed proteins were obtained (57 up-regulated, 43 down-regulated), among which thrombospondin-1 (THBS1) and cluster of differentiation 47 (CD47) were down-regulated. THBS1 was identified as the target of miR-222. Knockdown of THBS1 and CD47 increased mitochondrial Ca2+ level and decreased mitochondrial membrane potential (MMP) level. Together, our data establish a significant role of miR-222 in regulating mitochondrial dysfunction in response to TGEV infection.
Project description:Overexpression of miR-183-5p|+2, but not of the other two isomiRs |0 and |+1, was observed to reduce cell cycle and cell proliferation in different triple-negative breast cancer cell lines. Therefore, we hypothesized that the |+2 isoform has targets distinct from the other two isoforms. To test this hypothesis, we overexpressed separately the three different isoforms or negative controls (siAllstar or mimic-Cltr) and performed Mass Spectrometry to identify differentially regulated proteins. Interestingly, a gene set enrichment analysis of the changes in protein expression revealed significant downregulation of transcriptional targets of E2F specifically in cells transfected with the |+2 isoform prompting us to validate the predicted isomiR specific target E2F1. Subsequently, we could show that direct targeting of E2F1 by miR-183-5p|+2 is responsible for the impact of the isomiR on cell cycle and proliferation.
Project description:The product of genomic loci coding for micro RNAs (miRNAs) produce many isoforms (isomiRs). IsomiRs differing at their 5’ end have different seed regions and therefore are expected to target different genes. We used microarrays to study the effect of different isomiRs in the context of breast cancer. The product of genomic loci coding for micro RNAs (miRNAs) produce many isoforms (isomiRs). IsomiRs differing at their 5’ end have different seed regions and therefore are expected to target different genes. We used microarrays to study the effect of different isomiRs in the context of breast cancer. Breast cancer MDA-MB-231 cells were cultured and were subject to a negative control treatment or transfected with one of the three selected isomiRs: the archetype miRNA, the miR-183-5p|2|-2| or the miR-183-5p|+2|+2| isomiR. Each treatment was done in triplicate. RNA was extracted and hybridized on Affymetrix microarrays.
Project description:The identification of miRNAs’ targets and associated regulatory networks might allow the definition of new strategies using drugs whose association might mimic a given miRNA’s effects. Based on this assumption our group devised a multi-omics approach in an attempt to precisely characterize miRNAs’ effects. We combined the analysis of miR-491-5p direct targets, and effects at the transcriptomic and proteomic levels. We thus constructed an interaction network which enlightened highly connected nodes, being either direct or indirect targets of miR-491-5p effects: the already known EGFR and BCL2L1, but also EP300, CTNNB1 and several small-GTPases. By using different combinations of specific inhibitors of these nodes, we could greatly enhance their respective cytotoxicity and mimic miR-491-5p-induced phenotype. Our methodology thus constitutes an interesting strategy to comprehensively study the effects of a given miRNA. Also, we identified targets for which pharmacological inhibitors are already available for a clinical use, or in clinical trial phases. This study might thus enable innovative therapeutic options for ovarian cancer, which remains the first cause of death from gynecological malignancies in developed countries.
Project description:mRNA microarray experiments were performed to measure global mRNA expression in the presence of increased or decreased miR-106a-5p levels to to identify the total transcripts regulated by miR-106a-5p directly or indirectly. FASTK was identified as a direct target gene of miR-106a-5p. In order to identify the total transcripts regulated by miR-106a-5p directly or indirectly, we first measured the global mRNA expression change through mRNA microarray by overexpressing or knocking down miR-106a-5p in cancer cells. Next, we combined bioinformatics programs to select candidate miR-106a-5p targets from the differentially regulated genes to refine the number of miR-106a-5p targets. Then we validated the miR-106a-5p target gene through western blot analysis, quantitative real-time PCR and luciferase reporter assay.
Project description:The transition of the endothelium to a pro-inflammatory state is key to progression of chronic inflammatory diseases including rheumatoid arthritis, chronic bowel disease and atherosclerosis. In atherosclerosis it is hypothesized that low density lipoproteins (LDL) that become trapped in the intima of the blood vessels are oxidized to minimally modified LDL (mmLDL) and that these serve as an important contributing factors to endothelial dysfunction. Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (OX-PAPC), a model of the active phospholipid components of mmLDL affects the expression of hundreds of genes involved in inflammatory and other biological processes in human aortic endothelial cells (HAECs). We hypothesized that microRNAs (miRNAs) partially regulate this response. Using next generation sequencing, we identified miR-21-3p and miR-27a-5p to be induced 4-fold and 3-fold, respectively in response to OX-PAPC treatment compared to control treatment in HAECs. To identify the targets, we performed whole genome transcript profiling following transient over-expression of these two miRNAs followed by. In total, 1254 genes were down-regulated with 925 of them overlapping between the two miRNAs. Functional enrichment analysis using Gene Ontology predicted that the two miRNAs were involved in the regulation of NF-κB signaling. We characterized the Toll/interleukin-1 receptor (TIR) domain-containing adaptor protein TICAM2 as a direct target of miR-21-3p and miR-27a-5p. Furthermore, we showed that over-expression of miR-21-3p and miR-27a-5p lead to decreased p65 translocation to the nucleus and decreased the expression of known NF-κB downstream target genes confirming both miRNAs’ role in negatively regulating NF-κB signaling in endothelial cells. mRNA expression profiling of human aortic endothelial cells from two separate donors that were transfected with 1 nM microRNA mimics and negative control. The miRIDIAN mimics used were miR-21-3p (Catalog Number:C-301023-01-0005), miR-27a-5p (Catalog No: C-301028-01-0005), negative control (Catalog No: CN-001000-01-05)
Project description:Cellular targets for most of EBV miRNAs are not known. In our study, we aimed at identifying genes that are regulated by individual EBV mature miRNA, particularly BART 18-5p We used microarrays to explore the global gene expression (particularly the downregulated genes) targeted by EBV miRNA mimics. Burkitt's lymphoma cell lines, BL2 and BJAB, were transfected with miRNA mimic control (MC) and EBV miRNA mimics BART 18-5p, 10 and 14* for 24 hour prior to RNA extraction and hybridization on Affymetrix human HGU133 plus 2.0 microarrays.
Project description:The abnormal regulation of amyloid-b (Ab) metabolism (e.g., production, cleavage, clearance) plays a central role in Alzheimerâs disease (AD). Among endogenous factors believed to participate in AD progression are the small regulatory non-coding microRNAs (miRs). In particular, the miR-132/212 cluster is severely reduced in the AD brain. In previous studies we have shown that miR-132/212 deficiency in mice leads to impaired memory and enhanced Tau pathology as seen in AD patients. Here we demonstrate that the genetic deletion of miR-132/212 promotes Ab deposition and amyloid (senile) plaque formation in triple transgenic AD (3xTg-AD) mice. Using RNA-Seq and bioinformatics, we identified genes of the miR-132/212 network with documented roles in the regulation of Ab metabolism, including Tau, Mapk, and Sirt1. We used RNA-Seq to analyse the hippocampus of 3xTg-AD mice lacking the miR-132/212 cluster as well as Neuro2a cells overexpressing miR-132 mimics.
Project description:While microRNAs (miRs) have been extensively studied in the context of malignancy and tumor progression, their functions in regulating T cell activation are less clear. We found reduced levels of miR-15a/16 at 3-18 h post-T cell receptor (TCR) stimulation, suggesting a role in shaping T cell activation. An inducible miR15a/16 transgenic mouse model was developed to determine how elevating miR-15a/16 levels during early stages of activation would affect T cell proliferation and to identify TCR signaling pathways regulated by this miR pair. Doxycyclin (DOX) induced expression of miR-15a/16 from 0-18 h post-TCR stimulation decreased ex vivo proliferation as well as in vivo antigen-specific proliferation. Bioinformatic and proteomic approaches were combined to identify MEK1 as a target of miR-15a/16. MEK1 targeting by miR-15a/16 was confirmed using miR mimics that decreased MEK1 containing the 3’-UTR target nucleotide sequence (UGCUGCUA) but did not decrease MEK1 containing a mutated control sequence (AAAAAAAA). Phosphorylation of downstream signaling molecules ERK1/2 and Elk1 were decreased with DOX-induced miR-15a/16 expression. In addition to MEK1, ERK1 was subsequently found to be targeted by miR-15a/16, with DOX induced miR-15a/16 reducing total ERK1 levels in T cells. These findings show that TCR stimulation reduces miR-15a/16 levels at early stages of T cell activation to facilitate increased MEK1 and ERK1, and this promotes sustained MEK1-ERK1/2-Elk1 signaling required for optimal proliferation.