Project description:Skeletal muscle has a central role in whole body metabolism with myofibers that represent its functional units. These are differentiated cells with different contraction power and metabolic traits. Faster contracting myofibers preferentially use glucose as substrate for energy production, while slower use lipids. Myofibers can plastically change phenotypic traits in response to pathophysiological stimuli. Since post-transcriptional mechanisms should administer the changes of these post-mitotic cells, we demonstrated that miR-27a-3p influences myofiber fuel availability and mitochondrial morphology. In vitro and in vivo experiments demonstrate that miR-27a-3p regulates glycogen utilization. We used microarrays to characterize the global changes in gene expression in C2C12 myoblasts due to over-expression of miR-27a-3p.
Project description:Skeletal muscle has a central role in whole body metabolism with myofibers that represent its functional units. These are differentiated cells with different contraction power and metabolic traits. Faster contracting myofibers preferentially use glucose as substrate for energy production, while slower use lipids. Myofibers can plastically change phenotypic traits in response to pathophysiological stimuli. Since post-transcriptional mechanisms should administer the changes of these post-mitotic cells, we demonstrated that miR-142-3p influences myofiber fuel availability and mitochondrial morphology. In vitro and in vivo experiments demonstrate that miR-142-3p regulates lipids utilization. We used microarrays to characterize the global changes in gene expression in C2C12 myoblasts due to over-expression of miR-142-3p.
Project description:Expression Signatures of Single Isolated Myofibers of Mouse Hindlimb and miR-27a-3p or miR-142-3p overexpression in C2C12 myoblasts
Project description:MicroRNAs (miRNAs) are small noncoding RNAs that critically regulate gene expression. Their abundance and function have been linked to processes such as senescence and aging. In aged monkey muscle, miR-451a and miR-144-3p were highly upregulated compared to young animals. This led us to hypothesize that the miRNAs 451a/144-3p may be involved in muscle differentiation. We found that these miRNAs are downregulated during the differentiation of C2C12 myoblasts. Overexpression of miR-451a, but not miR-144-3p, robustly impeded the differentiation, suggesting an inhibitory role for miR-451a. We further investigated the potential regulatory targets of miR-451a and identified Sparc mRNA, encoding a secreted protein acidic and rich in cysteine (SPARC), which is involved in wound healing and cellular differentiation. Interestingly, we found that miR-451a suppresses Sparc mRNA translation according to the analysis of polysome profile. Our findings show that miR-451a is downregulated in differentiated myoblasts and decreases C2C12 differentiation at least in part by the suppression of SPARC biosynthesis.
Project description:The differentiation and regeneration of skeletal muscle from myoblasts to myotubes involves myogenic transcription factors, such as myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF). In addition, post-transcriptional regulation by miRNAs is required during myogenesis. Here we provide evidence for novel mechanisms regulating MRTF-A during myogenic differentiation. Endogenous MRTF-A protein abundance and activity decreased during C2C12 differentiation, which was attributable to miRNA-directed inhibition. Conversely, overexpression of MRTF-A impaired differentiation and myosin expression. Applying miRNA trapping by RNA affinity purification (miTRAP), we identified miRNAs which directly regulate MRTF-A via its 3’UTR, including miR-1a-3p, miR-206-3p, miR-24-3p and miR-486-5p. These miRNAs were upregulated during differentiation and specifically recruited to the 3’UTR of MRTF-A. Concomitantly, Ago2 recruitment to the MRTF-A 3’UTR was considerably increased, whereas Dicer1 depletion or 3’UTR deletion elevated MRTF-A and inhibited differentiation. MRTF-A protein expression was inhibited by ectopic miRNA expression in murine C2C12 and primary human myoblasts. 3'UTR reporter activity diminished upon differentiation or miRNA expression, whereas deletion of the predicted binding sites reversed these effects. Furthermore, TGF-β abolished MRTF-A reduction and decreased miR-486-5p expression. Our findings implicate miR-24-3p and miR-486-5p in the repression of MRTF-A and suggest a complex network of transcriptional and post-transcriptional mechanisms regulating myogenesis.
Project description:We have recently confirmed miR-27a-3p as a crucial regulator of human adipogenesis (Wu H, Pula T, Tews D, Amri E-Z, Debatin K-M, Wabitsch M, Fischer-Posovszky P, Roos J. microRNA-27a-3p but Not -5p Is a Crucial Mediator of Human Adipogenesis. Cells. 2021; 10(11):3205. https://doi.org/10.3390/cells10113205 ). MiR-27a-5p did not impair human adipogenesis. However, since several publications state that miR-27a ist also a crucial regulator of UCP1, we were interested if miR-27a-3p or miR-27a-5p regulatas UCP1 and other thermogenesis related genes. We found a strong regulation of UCP1 with functional relevance for the cellular metabolism by miR-27a-5p.To asesse the mRNA gene expression pattern, mRNA sequencing was performed.
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:Background: MicroRNAs (miRNAs) are a family of small, non-coding single-stranded RNA molecules involved in post-transcriptional regulation of gene expression. As such, they are believed to play a role in regulating the step-wise changes in gene expression patterns that occur during cell fate specification of multipotent stem cells. Here, we have studied whether terminal differentiation of C2C12 myoblasts is indeed controlled by lineage-specific changes in miRNA expression. Results: Using a previously generated RNA polymerase II (Pol-II) ChIP-on-chip dataset, we show differential Pol-II occupancy at the promoter regions of six miRNAs during C2C12 myogenic versus BMP2-induced osteogenic differentiation. Overexpression of one of these miRNAs, miR-378, enhances Alp activity, calcium deposition and mRNA expression of osteogenic marker genes in the presence of BMP2. Conclusions: Our results demonstrate a previously unknown role for miR-378 in promoting BMP2-induced osteogenic differentiation. Stable C2C12 cell lines C2C12-pMirn0 and C2C12-pMirn378 were generated by lentiviral transduction of C2C12 myoblasts with a Mirn378-overexpression construct and its parent vector, respectively. C2C12-pMirn0 and C2C12-pMirn378 cells were plated at 2.5 x 10^4 cells/cm2 (day -1), cultured for 1 day in DMEM 10%NCS, then (d0) treated with or without 300 ng/ml bone morphogenetic protein 2 (BMP2) for 6 days. RNA was extracted on d0, d3 and d6 and hybridized to GeneChip Mouse Genome 430 2.0 array (Affymetrix).
Project description:Gene expression profiling was carried out in Huh-7.5 cells in which miR-27a was over- or under-expressed. Transfection of cells with pre-miR-27a and pre-miR-control, or anti-miR-27a and anti-miR-control enabled down- and up-regulated genes to be determined, respectively. Replication and infectivity of the lipotrophic hepatitis C virus (HCV) is regulated by cellular lipid status. Among differentially expressed micro (mi)RNAs, we found that miR-27a was preferentially expressed in HCV-infected compared with hepatitis B virus (HBV)-infected liver. Gene expression profiling of Huh-7.5 cells showed that miR-27a regulates lipid metabolism by targeting the lipid synthetic transcriptional factor, RXRα, and the lipid transporter, ABCA1 Carrying out a Target Scan (Release 5.2) of miR-27a predicted 921 candidate target genes, and functional gene ontology enrichment analysis of these genes by MetaCore (Thomson Reuters, NY) showed that miR-27a could target the signaling pathways of cytoskeleton remodeling and lipid metabolism . To examine whether these signaling pathways were regulated by miR-27a, gene expression profiling was carried out in Huh-7.5 cells in which miR-27a was over- or under-expressed. Transfection of cells with pre-miR-27a and pre-miR-control, or anti-miR-27a and anti-miR-control enabled down- and up-regulated genes to be determined, respectively. Huh-7.5 cells with miR-27a over- or under-expressed