title: The Robo4 cytoplasmic domain is dispensable for vascular permeability and neovascularization.
abstract: Vascular permeability and neovascularization are implicated in many diseases including retinopathies and diabetic wound healing. Robo4 is an endothelial-specific transmembrane receptor that stabilizes the vasculature, as shown in Robo4-/-mice that develop hyperpermeability, but how Robo4 signals remained unclear. Here we show that Robo4 deletion enhances permeability and revascularization in oxygen-induced retinopathy (OIR) and accelerates cutaneous wound healing. To determine Robo4 signalling pathways, we generated transgenic mice expressing a truncated Robo4 lacking the cytoplasmic domain (Robo4ΔCD). Robo4ΔCD expression is sufficient to prevent permeability, and inhibits OIR revascularization and wound healing in Robo4-/-mice. Mechanistically, Robo4 does not affect Slit2 signalling, but Robo4 and Robo4ΔCD counteract Vegfr2-Y949 (Y951 in human VEGFR2) phosphorylation by signalling through the endothelial UNC5B receptor. We conclude that Robo4 inhibits angiogenesis and vessel permeability independently of its cytoplasmic domain, while activating VEGFR2-Y951 via ROBO4 inhibition might accelerate tissue revascularization in retinopathy of prematurity and in diabetic patients.
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Prahst
authors.affiliation: INSERM U970, Paris Center for Cardiovascular Research (PARCC), 75015 Paris, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mathivet
authors.affiliation: INSERM U970, Paris Center for Cardiovascular Research (PARCC), 75015 Paris, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Pibouin-Fragner
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.
authors.forename: Jiasheng
authors.identifier: 0000-0002-4637-5655
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.
authors.forename: Gael
authors.initials: G
authors.lastname: Genet
authors.affiliation: Genentech Inc., Molecular Oncology Division, South San Francisco, California 94030, USA.
authors.forename: Raymond
authors.initials: R
authors.lastname: Tong
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.
authors.forename: Alexandre
authors.identifier: 0000-0002-3829-2577
authors.initials: A
authors.lastname: Dubrac
authors.affiliation: Cardiovascular Research Center, Yale University School of Medicine, Department of Internal Medecine Cardiology, New Haven, Connecticut 06510-3221, USA.|INSERM U970, Paris Center for Cardiovascular Research (PARCC), 75015 Paris, France.|Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510-3221, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Eichmann
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000235:genetics*; D003930:Diabetic Retinopathy; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009389:Neovascularization, Pathologic / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D000075386:Netrin Receptors / Q000378:metabolism; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects; D010766:Phosphorylation; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic / Q000235:genetics* / Q000378:metabolism; D012164:Retinal Diseases / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D012178:Retinopathy of Prematurity; D015398:Signal Transduction; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D014945:Wound Healing / Q000235:genetics; D000098552:Slit Homolog 2 Protein
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D000075386:Netrin Receptors; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C540792:Robo4 protein, mouse; C000617307:Unc5b protein, mouse; D040301:Vascular Endothelial Growth Factor Receptor-2; D000098552:Slit Homolog 2 Protein