title: Transcriptional fine-tuning of microRNA-223 levels directs lineage choice of human hematopoietic progenitors.
abstract: MicroRNAs (miRNAs) regulate cell proliferation, differentiation and death during development and postnatal life. The expression level of mature miRNAs results from complex molecular mechanisms, including the transcriptional regulation of their genes. MiR-223 is a hematopoietic-specific miRNA participating in regulatory signaling networks involving lineage-specific transcription factors (TFs). However, the transcriptional mechanisms governing its expression levels and its functional role in lineage fate decision of human hematopoietic progenitors (HPCs) have not yet been clarified. We found that in CD34(+)HPCs undergoing unilineage differentiation/maturation, miR-223 is upregulated more than 10-fold during granulopoiesis, 3-fold during monocytopoiesis and maintained at low levels during erythropoiesis. Chromatin immunoprecipitation and promoter luciferase assays showed that the lineage-specific expression level of mature miR-223 is controlled by the coordinated binding of TFs to their DNA-responsive elements located in 'distal' and 'proximal' regulatory regions of the miR-223 gene, differentially regulating the transcription of two primary transcripts (pri-miRs). All this drives myeloid progenitor maturation into specific lineages. Accordingly, modulation of miR-223 activity in CD34(+)HPCs and myeloid cell lines significantly affects their differentiation/maturation into erythroid, granulocytic and monocytic/macrophagic lineages. MiR-223 overexpression increases granulopoiesis and impairs erythroid and monocytic/macrophagic differentiation. Its knockdown, meanwhile, impairs granulopoiesis and facilitates erythropoiesis and monocytic/macrophagic differentiation. Overall, our data reveal that transcriptional pathways acting on the differential regulation of two pri-miR transcripts results in the fine-tuning of a single mature miRNA expression level, which dictates the lineage fate decision of hematopoietic myeloid progenitors.
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, University of Rome 'La Sapienza', Latina 04100, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Vian
authors.affiliation: Department of Clinical and Experimental Medicine, General Pathology, University of Perugia, Perugia 06100, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Di Carlo
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Pelosi
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, University of Rome 'La Sapienza', Latina 04100, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fazi
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Santoro
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy.
authors.forename: A M
authors.initials: AM
authors.lastname: Cerio
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Boe
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, University of Rome 'La Sapienza', Latina 04100, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Rotilio
authors.affiliation: Department of Clinical and Experimental Medicine, General Pathology, University of Perugia, Perugia 06100, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Billi
authors.affiliation: Department of Clinical and Experimental Medicine, General Pathology, University of Perugia, Perugia 06100, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Racanicchi
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy.
authors.forename: U
authors.initials: U
authors.lastname: Testa
authors.affiliation: Department of Clinical and Experimental Medicine, General Pathology, University of Perugia, Perugia 06100, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Grignani
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, University of Rome 'La Sapienza', Latina 04100, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Nervi
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D019070:Cell Lineage / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D018952:Antigens, CD34; D035683:MicroRNAs; C525067:MIR223, human