Project description:Peripheral Artery Disease is caused by the restriction or occlusion of arteries supplying the leg. Better understanding of the molecular mechanisms underpinning tissue response to acute and chronic ischemia is urgently needed to improve therapeutic options. The aim of this study is understanding miR-210 regulation and role in a mouse model of hindlimb ischemia. To investigate miR-210 function, mice were injected with a miR-210 complementary LNA-oligonucleotide (anti-miR-210). Then, the left femoral artery was dissected in order to induce unilateral hindlimb ischemia. Mice were sacrified 3 days later and gene expression profiles of gastrocnemius muscles were obatained.
Project description:Peripheral Artery Disease is caused by the restriction or occlusion of arteries supplying the leg. Better understanding of the molecular mechanisms underpinning tissue response to acute and chronic ischemia is urgently needed to improve therapeutic options. The aim of this study is understanding miR-210 regulation and role in a mouse model of hindlimb ischemia.
Project description:Hypoxia is known to regulate tumor-initiating cells and to have an effect on miRNA expression. We were interested in studying the role of hypoxia-induced miR-210 in colorectal cancer patient-derived sphere cultures. Downregulated genes after overexpression of miR-210 were retained as potential miR-210 target genes for further validation sudies.
Project description:MicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. Previously, we demonstrated that miR-210 is a key player of endothelial cell (EC) response to hypoxia, modulating EC survival, migration and ability to form capillary like-structures. Moreover, the receptor tyrosine kinase ligand Ephrin-A3 was identified as one functionally relevant target. Since each miRNA regulates hundreds of mRNAs, different approaches were combined to identify new miR-210 targets: a Using target prediction software, 32 new miR-210 potential targets were identified. b The proteomic profiling of miR-210 over-expressing ECs identified 11 proteins that were specifically inhibited by miR-210, either directly or indirectly. c Affymetrix based gene expression profiles identified 51 genes that were both down-modulated by miR-210 over-expression and de-repressed when miR-210 was blocked. Surprisingly, only few genes identified either by proteomics or transcriptomics were recognized as miR-210 targets by target prediction algorithms. However, a low-stringency pairing research revealed enrichment for miR-210 putative binding sites, raising the possibility that these genes were targeted via non-canonical recognition sequences. To clarify this issue, miR-210-loaded RISC was purified by immuno-precipitation along with its mRNA targets. The presence of Ephrin-A3 mRNA in the complex validated this approach. We found that 32 potential targets were indeed enriched in miR-210-loaded RISC, and thus can be considered as genuine miR-210 targets. In keeping with this conclusion, we were able to further validate a sub-set of them by 3âUTR-reporter assays. Gene ontology analysis of the targets confirmed the known miR-210 activity in differentiation and cell cycle regulation, highlighting new functions such as involvement in RNA processing, DNA binding, development, membrane trafficking and amino acid catabolism. In conclusion, we validated a multidisciplinary approach for miRNAs target identification and indicated novel molecular mechanisms underpinning miR-210 role in EC response to hypoxia. Experiment Overall Design: Gene expression modifications induced by both miR-210 over-expression and blockade were evaluated. In order to identify new direct and indirect miR-210 targets, transcripts repressed by miR-210 over-expression and up-regulated by miR-210 inhibition (and vice versa) were selected.
Project description:MicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. miR-210 can be considered a master miRNA of hypoxic response and is currently regarded as a promising novel non-invasive tumor hypoxia marker. The targets identified to date indicate that miR-210 plays a role in cell cycle regulation, differentiation, mitochondrial metabolism repression, DNA repair and apoptosis. In order to identify miRNAs sub-sequentely modulated by miR-210, miRNA expression profiles of human umbilical vein endothelial cells (HUVEC) over-expressing miR-210 were generated, allowing the identification of miRNAs modulated upon miR-210 up-regulation. HUVEC over-expressing pre-miR-210 or a scramble sequence were generated by retroviral infection, yielding a selected population that expressed mature miR-210 levels comparable with those observed in hypoxic cells. miRNA expression profiles were then measured and miRNAs modulated upon miR-210 up-regulation were identified. This Sample represents four hybridizations - one of which was a dye-swap.
Project description:MicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. miR-210 can be considered a master miRNA of hypoxic response and is currently regarded as a promising novel non-invasive tumor hypoxia marker. The targets identified to date indicate that miR-210 plays a role in cell cycle regulation, differentiation, mitochondrial metabolism repression, DNA repair and apoptosis. In order to identify miRNAs sub-sequentely modulated by miR-210, miRNA expression profiles of human umbilical vein endothelial cells (HUVEC) over-expressing miR-210 were generated, allowing the identification of miRNAs modulated upon miR-210 up-regulation.
Project description:In order to understand the consequences of miR-210 blocking on the ischemia response, the transcriptomic changes were investigated by microarray technology in gastrocnemius muscles of ANTI-210 and SCR treated mice, 7 days after ischemia. Identified differentially expressed genes were used to perform gene-ontology enrichment-analysis, allowing to identify several terms falling into the biological macro areas of angiogenesis and blood vessel development, as well as related categories, such as cell adhesion, migration and proliferation. These findings are in agreement with the identified positive role played by miR-210 in the neo-vascularization process. Furthermore, many terms were also related to metabolism and mitochondrial organization, in keeping with the role of miR-210 in the regulation of oxidative phosphorylation.
Project description:MicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. Previously, we demonstrated that miR-210 is a key player of endothelial cell (EC) response to hypoxia, modulating EC survival, migration and ability to form capillary like-structures. Moreover, the receptor tyrosine kinase ligand Ephrin-A3 was identified as one functionally relevant target. Since each miRNA regulates hundreds of mRNAs, different approaches were combined to identify new miR-210 targets: a Using target prediction software, 32 new miR-210 potential targets were identified. b The proteomic profiling of miR-210 over-expressing ECs identified 11 proteins that were specifically inhibited by miR-210, either directly or indirectly. c Affymetrix based gene expression profiles identified 51 genes that were both down-modulated by miR-210 over-expression and de-repressed when miR-210 was blocked. Surprisingly, only few genes identified either by proteomics or transcriptomics were recognized as miR-210 targets by target prediction algorithms. However, a low-stringency pairing research revealed enrichment for miR-210 putative binding sites, raising the possibility that these genes were targeted via non-canonical recognition sequences. To clarify this issue, miR-210-loaded RISC was purified by immuno-precipitation along with its mRNA targets. The presence of Ephrin-A3 mRNA in the complex validated this approach. We found that 32 potential targets were indeed enriched in miR-210-loaded RISC, and thus can be considered as genuine miR-210 targets. In keeping with this conclusion, we were able to further validate a sub-set of them by 3’UTR-reporter assays. Gene ontology analysis of the targets confirmed the known miR-210 activity in differentiation and cell cycle regulation, highlighting new functions such as involvement in RNA processing, DNA binding, development, membrane trafficking and amino acid catabolism. In conclusion, we validated a multidisciplinary approach for miRNAs target identification and indicated novel molecular mechanisms underpinning miR-210 role in EC response to hypoxia.
Project description:Hypoxia in the tumor microenvironment plays a crucial role in the evasion of immune surveillance by tumor cells. In this study, we aimed to identify the miRs regulated by hypoxia in NSCLC and melanoma and their putative involvement in the regulation of tumor susceptibility to antigen-specific cytotoxic T lymphocyte (CTL)-mediated killing. MicroRNA-210 (miR-210) was significantly induced in a hypoxia inducible factor 1 alpha (HIF-1_) dependent manner in NSCLC and melanoma cells. We show for the first time that miR-210 was expressed in hypoxic zones of human NSCLC tissues. Transfection of anti-miR-210 in both hypoxic NSCLC and melanoma cells resulted in a significant restoration of their susceptibility to autologous CTL-mediated lysis, independent of tumor cell recognition and CTL reactivity. A comprehensive approach using transcriptome analysis and argonaute protein immunoprecipitation indicated that PTPN, HOXA1and TP53I11 were regulated by miR-210 in hypoxic IGR-Heu cells. Simultaneous silencing of PTPN, HOXA1 and TP53I11 resulted in a dramatic decrease in target susceptibility to CTL-mediated lysis. This is the first report showing that hypoxia-induced miR-210 regulates tumor cell susceptibility to CTL-mediated lysis in part by suppressing PTPN, HOXA1 and TP53I11 expression. These studies suggest that miR-210 plays a potential role in the regulation of anti-tumor immune responses. The experience consists in 16 hybridizations on human miRNA Agilent arrays in one color, with 2 types of cell lines (HeuN and Na8) and 3 time of hypoxy induction (1% O2) (6, 16 and 24 hours) in comparison with normoxy (21% O2) at t=0. The hybridizations are made in replicates.
Project description:The resistance of hypoxic cells to radiotherapy and chemotherapy is a major problem in the treatment of cancer. Recently, an additional level of Hypoxia Inducible Factor (HIF) dependent transcriptional regulation has emerged involving modulation of a specific set of miRNAs including miR-210. We have recently shown that HIF-1 induction of miR-210 also stabilizes HIF-1 through a positive regulatory loop. We therefore hypothesized that by stabilizing HIF-1 in normoxia, miR-210 may protect cancer cells from radiation. We developed Non-Small Cell Lung Cancer (NSCLC)-derived cell lines (A549 and H1975) stably expressing miR-210 (pmiR-210) or a control miRNA (pmiR-Ctl). MiR-210 expressing cells showed a significant stabilization of HIF-1 associated with mitochondrial defects and a glycolytic phenotype. The cells were subjected to radiation levels ranging from 0 to 10Gy in normoxia and hypoxia. Cells expressing miR-210 in normoxia had the same level of resistance than control cells in hypoxia. pmiR-210 cells under hypoxia showed a low mortality rate due to a decrease in apoptosis and an ability to grow even at 10Gy. We have established that radioresistance was independent of p53 and cell cycle status. In addition, we show here that genomic double strand breaks (DSB) foci disappeared faster in pmiR-210 than in pmiR-Ctl cells, suggesting that miR-210 expression promotes a more efficient DSB repair. Finally, HIF-1 invalidation in pmiR-210 cells (pmiR-210/HIF-1-) abolished radioresistance of cells showing that this mechanism was dependent upon HIF-1. In conclusion, miR-210 appears to be a major component in the radioresistance of hypoxic cancer cells. Given the high stability of most miRNAs, this advantage could even be used by tumor cells in conditions where hypoxia may not be present anymore and strongly suggests that strategies targeting miR-210 would enhance tumor radiosensitization.