title: MicroRNA expression patterns and function in endodermal differentiation of human embryonic stem cells.
abstract: OBJECTIVE
  microRNAs (miRNAs) are small noncoding RNAs that regulate cognate mRNAs post-transcriptionally. Human embryonic stem cells (hESC), which exhibit the characteristics of pluripotency and self-renewal, may serve as a model to study the role of miRNAs in early human development. We aimed to determine whether endodermally-differentiated hESC demonstrate a unique miRNA expression pattern, and whether overexpression of endoderm-specific miRNA may affect hESC differentiation.
  
  
  METHODS
  miRNA expression was profiled in undifferentiated and NaButyrate-induced differentiated hESC of two lines, using microarray and quantitative RT-PCR. Then, the effect of lentiviral-based overexpression of liver-specific miR-122 on hESC differentiation was analyzed, using genomewide gene microarrays.
  
  
  RESULTS
  The miRNA profiling revealed expression of three novel miRNAs in undifferentiated and differentiated hESC. Upon NaButyrate induction, two of the most upregulated miRNAs common to both cell lines were miR-24 and miR-10a, whose target genes have been shown to inhibit endodermal differentiation. Furthermore, induction of several liver-enriched miRNAs, including miR-122 and miR-192, was observed in parallel to induction of endodermal gene expression. Stable overexpression of miR-122 in hESC was unable to direct spontaneous differentiation towards a clear endodermal fate, but rather, delayed general differentiation of these cells.
  
  
  CONCLUSIONS
  Our results demonstrate that expression of specific miRNAs correlates with that of specific genes upon differentiation, and highlight the potential role of miRNAs in endodermal differentiation of hESC.
authors.affiliation: Goldyne Savad Institute of Gene Therapy, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: Galit
authors.initials: G
authors.lastname: Tzur
authors.forename: Asaf
authors.initials: A
authors.lastname: Levy
authors.forename: Eti
authors.initials: E
authors.lastname: Meiri
authors.forename: Omer
authors.initials: O
authors.lastname: Barad
authors.forename: Yael
authors.initials: Y
authors.lastname: Spector
authors.forename: Zvi
authors.initials: Z
authors.lastname: Bentwich
authors.forename: Lina
authors.initials: L
authors.lastname: Mizrahi
authors.forename: Mark
authors.initials: M
authors.lastname: Katzenellenbogen
authors.forename: Etti
authors.initials: E
authors.lastname: Ben-Shushan
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Reubinoff
authors.forename: Eithan
authors.initials: E
authors.lastname: Galun
mesh_terms: D000465:Algorithms; D002454:Cell Differentiation; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology*; D004707:Endoderm / Q000378:metabolism*; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005822:Genetic Vectors; D015894:Genome, Human; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012978:Sodium Oxybate / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D014157:Transcription Factors; D012978:Sodium Oxybate