title: Preeclampsia up-regulates angiogenesis-associated microRNA (i.e., miR-17, -20a, and -20b) that target ephrin-B2 and EPHB4 in human placenta.
abstract: BACKGROUND
  Placental angiogenesis contributes to the pathogenesis of preeclampsia (PE) that affects 5-8% of all human pregnancies. MicroRNA (miRNA) are a class of noncoding 21- to 25-nucleotide RNA that negatively regulate gene expression posttranscriptionly.
  
  
  OBJECTIVE
  The aim of this study was to test the hypothesis that miRNA are differentially expressed in healthy term and PE placentas and a subclass of angiogenesis-associated miRNA are increased by PE.
  
  
  METHODS
  Total miRNA were extracted from villous placental tissues from healthy term and severe preeclamptic pregnancies. Differential miRNA expression was analyzed by microarray and real-time quantitative PCR. Angiogenesis-associated miRNA were analyzed by target prediction databases. In situ hybridization was used to localize miRNA. Target verification was performed by transfection of miRNA precursors or antagomirs into endothelial and BeWo cells and luciferase reporter assays.
  
  
  RESULTS
  Three highly expressed miRNA (miR-17, -20a, and -20b) were found significantly increased in PE compared with healthy term placentas (n = 10 per group). They target on the same group of genes important for angiogenesis. miR-20b was expressed primarily in villous syncytiotrophoblasts in term placenta. Overexpression or inhibition of miR-20b differentially regulated mRNA expression of those genes in endothelial vs. trophoblast cells. Luciferase reporter assay showed that miR-20b targets EPHB4 and ephrin-B2 that have been shown to be critical for early human placental development. Placental ephrin-B2 mRNA was significantly down-regulated in PE compared with normotensive pregnancies.
  
  
  CONCLUSIONS
  miR-17, miR-20a, and miR-20b are differentially regulated in human placentas by PE. They regulate EPHB4 and ephrin-B2 expression in trophoblast and endothelial cells via the same "seed" sequence, suggesting their roles in early placental development.
authors.affiliation: Department of Obstetrics and Gynecology, University of California Irvine, Irvine, California 92697, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.forename: Honghai
authors.initials: H
authors.lastname: Zhang
authors.forename: Stephanie
authors.initials: S
authors.lastname: Hachy
authors.forename: Seiro
authors.initials: S
authors.lastname: Satohisa
authors.forename: Louise C
authors.initials: LC
authors.lastname: Laurent
authors.forename: Mana
authors.initials: M
authors.lastname: Parast
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.forename: Dong-bao
authors.initials: DB
authors.lastname: Chen
mesh_terms: D036388:Ephrin-B2 / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics; D035683:MicroRNAs / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology; D010920:Placenta / Q000098:blood supply / Q000502:physiology*; D011225:Pre-Eclampsia / Q000235:genetics* / Q000378:metabolism; D011247:Pregnancy; D036224:Receptor, EphB4 / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
chemical_list: D036388:Ephrin-B2; C524941:MIRN17 microRNA, human; C534451:MIRN20a microRNA, human; D035683:MicroRNAs; D008156:Luciferases; D036224:Receptor, EphB4