title: CD34+ hematopoietic stem-progenitor cell microRNA expression and function: a circuit diagram of differentiation control.
abstract: MicroRNAs (miRNAs) are a recently identified class of epigenetic elements consisting of small noncoding RNAs that bind to the 3' untranslated region of mRNAs and down-regulate their translation to protein. miRNAs play critical roles in many different cellular processes including metabolism, apoptosis, differentiation, and development. We found 33 miRNAs expressed in CD34+ hematopoietic stem-progenitor cells (HSPCs) from normal human bone marrow and mobilized human peripheral blood stem cell harvests. We then combined these data with human HSPC mRNA expression data and with miRNA-mRNA target predictions, into a previously undescribed miRNA:mRNA interaction database called the Transcriptome Interaction Database. The in silico predictions from the Transcriptome Interaction Database pointed to miRNA control of hematopoietic differentiation through translational control of mRNAs critical to hematopoiesis. From these predictions, we formulated a model for miRNA control of stages of hematopoiesis in which many of the genes specifying hematopoietic differentiation are expressed by HSPCs, but are held in check by miRNAs until differentiation occurs. We validated miRNA control of several of these target mRNAs by demonstrating that their translation in fact is decreased by miRNAs. Finally, we chose miRNA-155 for functional characterization in hematopoiesis, because we predicted that it would control both myelopoiesis and erythropoiesis. As predicted, miRNA-155 transduction greatly reduced both myeloid and erythroid colony formation of normal human HSPCs.
authors.affiliation: Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21204, USA. rgeorgan@jhmi.edu
authors.forename: Robert W
authors.initials: RW
authors.lastname: Georgantas
authors.forename: Richard
authors.initials: R
authors.lastname: Hildreth
authors.forename: Sebastien
authors.initials: S
authors.lastname: Morisot
authors.forename: Jonathan
authors.initials: J
authors.lastname: Alder
authors.forename: Chang-gong
authors.initials: CG
authors.lastname: Liu
authors.forename: Shelly
authors.initials: S
authors.lastname: Heimfeld
authors.forename: George A
authors.initials: GA
authors.lastname: Calin
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Croce
authors.forename: Curt I
authors.initials: CI
authors.lastname: Civin
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology*; D001665:Binding Sites; D002454:Cell Differentiation; D041905:Erythroid Cells / Q000166:cytology; D005786:Gene Expression Regulation; D018922:HL-60 Cells; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008954:Models, Biological; D022423:Myeloid Cells / Q000166:cytology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion
chemical_list: D018952:Antigens, CD34; D035683:MicroRNAs; D012333:RNA, Messenger