title: Shear stress-activated Wnt-angiopoietin-2 signaling recapitulates vascular repair in zebrafish embryos.
abstract: OBJECTIVE
  Fluid shear stress intimately regulates vasculogenesis and endothelial homeostasis. The canonical Wnt/β-catenin signaling pathways play an important role in differentiation and proliferation. In this study, we investigated whether shear stress activated angiopoietin-2 (Ang-2) via the canonical Wnt signaling pathway with an implication in vascular endothelial repair.
  
  
  RESULTS
  Oscillatory shear stress upregulated both TOPflash Wnt reporter activities and the expression of Ang-2 mRNA and protein in human aortic endothelial cells accompanied by an increase in nuclear β-catenin intensity. Oscillatory shear stress-induced Ang-2 and Axin-2 mRNA expression was downregulated in the presence of a Wnt inhibitor, IWR-1, but was upregulated in the presence of a Wnt agonist, LiCl. Ang-2 expression was further downregulated in response to a Wnt signaling inhibitor, DKK-1, but was upregulated by Wnt agonist Wnt3a. Both DKK-1 and Ang-2 siRNA inhibited endothelial cell migration and tube formation, which were rescued by human recombinant Ang-2. Both Ang-2 and Axin-2 mRNA downregulation was recapitulated in the heat-shock-inducible transgenic Tg(hsp70l:dkk1-GFP) zebrafish embryos at 72 hours post fertilization. Ang-2 morpholino injection of Tg (kdrl:GFP) fish impaired subintestinal vessel formation at 72 hours post fertilization, which was rescued by zebrafish Ang-2 mRNA coinjection. Inhibition of Wnt signaling with IWR-1 also downregulated Ang-2 and Axin-2 expression and impaired vascular repair after tail amputation, which was rescued by zebrafish Ang-2 mRNA injection.
  
  
  CONCLUSIONS
  Shear stress activated Ang-2 via canonical Wnt signaling in vascular endothelial cells, and Wnt-Ang-2 signaling is recapitulated in zebrafish embryos with a translational implication in vascular development and repair.
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Rongsong
authors.initials: R
authors.lastname: Li
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Tyler
authors.initials: T
authors.lastname: Beebe
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Nelson
authors.initials: N
authors.lastname: Jen
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Wakako
authors.initials: W
authors.lastname: Takabe
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Michael
authors.initials: M
authors.lastname: Harrison
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Hung
authors.initials: H
authors.lastname: Cao
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Juhyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Yang
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Peidong
authors.initials: P
authors.lastname: Han
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Kevin
authors.initials: K
authors.lastname: Wang
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Shimizu
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Jaunian
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Ching-Ling
authors.initials: CL
authors.lastname: Lien
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Chi
authors.affiliation: From the Department of Medicine, School of Medicine (R.L., T.K.H.), Department of Bioengineering (T.B., N.J., F.Y., W.T., H.C., J.L., T.K.H.), and Department of Molecular, Cell, and Developmental Biology (K.W., H.S., J.C.), University of California, Los Angeles; Department of Surgery, Children's Hospital Los Angeles, CA (M.H., C.-L.L.); and Division of Cardiology, Department of Medicine, School of Medicine (H.Y., P.H., N.C.C.) and Institute of Genomic Medicine (N.C.C.), University of California, San Diego, La Jolla. thsiai@mednet.ucla.edu.
authors.forename: Tzung K
authors.initials: TK
authors.lastname: Hsiai
mesh_terms: D042702:Angiopoietin-2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D060466:Axin Protein / Q000235:genetics / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D018919:Neovascularization, Physiologic / Q000187:drug effects; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D013312:Stress, Physiological; D013997:Time Factors; D014162:Transfection; D060449:Wnt Signaling Pathway / Q000187:drug effects; D060509:Wnt3A Protein / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C586513:ANGPT2 protein, human; D042702:Angiopoietin-2; D060466:Axin Protein; C501126:DKK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; C555510:WNT3A protein, human; D060509:Wnt3A Protein; D029961:Zebrafish Proteins; C501128:dkk1b protein, zebrafish; D049452:Green Fluorescent Proteins
keywords: DKK-1/dickkopfs-1; Wnt signaling; angiopoietin-2; endothelial repairs; human aortic endothelial cells (HAEC); vasculogenesis; zebrafish