Project description:Primary Myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by hyperplastic megakaryopoiesis and myelofibrosis. Through a gene expression profile (GEP) study we recently highlighted the upregulationof miR-34a-5p in PMF versus healthy donor (HD) CD34+ hematopoietic progenitor cells (HPCs). To shed some light into the role of miR-34a-5p in PMF pathogenesis, here we unravelled the effects of the overexpression of miR-34a-5p in HPCs forcing its expression in HPCs. We showed that enforced expression of miR-34a-5p blocks proliferation and favours the megakaryocyte and monocyte/macrophage commitment of HPCs. Interestingly, we identified lymphoid enhancer-binding factor 1 (LEF1) and nuclear receptor subfamily 4, group A, member 2 (NR4A2) transcripts as miR-34a-5p-targets downregulated after miR-34a-5p overexpression in HPCs as well as in PMF compared with HD HPCs. Remarkably, the knockdown of NR4A2 in HPCs mimicked the antiproliferative effects of miR-34a-5p overexpression, while the silencing of LEF1 phenocopied the effects of miR-34a-5p overexpression in HPCs lineage choice, by stimulating the megakaryocyte and monocyte/macrophage commitment.
Project description:In order to identify the targets of miR-193a-5p in osteosarcoma U2OS cell line, we used a lentivirus-mediated expression system to overexpressing miR-193a precusor, miR-193a-5p target sequence and non-target sequence, respectively, in osteosarcoma cell line U2OS. A tandem mass tag (TMT)-based quantitative proteomic strategy was employed to identify the global profile of miR-193a-5p-regulated proteins. order to identify the targets of miR-193a-5p, we used a lentivirus-mediated expression system to overexpressing miR-193a precusor, miR-193a-5p target sequence and non-target sequence, respectively, in osteosarcoma cell line U2OS. A tandem mass tag (TMT)-based quantitative proteomic strategy was employed to identify the global profile of miR-193a-5p-regulated proteins.
Project description:The transcription factor c-Myb plays a key role in human primary CD34+ hematopoietic progenitor cells (HPCs) lineage choice, by enhancing erythropoiesis at the expense of megakaryopoiesis. We previously demonstrated that c-Myb affects erythroid versus megakaryocyte lineage decision in part by transactivating KLF1 and LMO2 expression. To further unravel the molecular mechanisms through which c-myb affects lineage fate decision, we profiled the miRNA and mRNA changes in myb-silenced CD34+ HPCs. The integrative analysis of miRNA/mRNA expression changes upon c-myb silencing in human CD34+ HPCs highlighted a set of 19 miRNA with 150 anticorrelated putative target mRNAs. Among the miRNAs downregulated in myb-silenced progenitors with the highest number of predicted target mRNAs, we selected hsa-miR-486-3p based on the in vitro effects of its overexpression on HPCs commitment. Indeed, morphological and flow cytometric analyses after liquid culture showed that hsa-miR-486-3p overexpression in HPCs enhanced erythroid and granulocyte differentiation while restraining megakaryocyte and macrophage differentiation. Moreover, collagen-based clonogenic assay demonstrated a strong impairement megakaryocyte commitment upon hsa-miR-486-3p overexpression in CD34+ cells. Moreover, in order to identify the mRNA target through which hsa-miR-486-3p affects lineage fate decision, we profiled the mRNA changes in mimic transfected CD34+ HPC by means of Affymetrix GeneAtlas U219 strip array. Gene expression profiling of hsa-miR-486-3p overexpressing CD34+ cells enabled us to identify a set of 8 genes downregulated and computationally predicted, putative hsa-miR-486-3p targets. Among them, we selected c-maf transcript as upregulated upon myb silencing. Worth of note, c-maf silencing in CD34+ progenitor cells was able to reverse the affects of myb silencing on erythroid versus megakaryocyte lineage choice. Integrative miRNA/mRNA analysis highlighted a set of miRNAs and anticorrelated putative target mRNAs modulated upon myb silencing, therefore potential players in myb-driven HPCs lineage choice. Among them, we demonstrated the hsa-miR-486-3p/c-maf pair as partially contributing to the effects of myb on HPCs commitment. Therefore, our data collectively identified myb-driven hsa-miR-486-3p upregulation and subsequent c-maf downregulation as a new molecular mechanism through which cMyb favours erythropoiesis while restraining megakaryopoiesis. Gene expression profile (GEP) was performed on total RNA derived from three independent experiments at 24h after the last nucleofection.