title: Cdc42 is required for cytoskeletal support of endothelial cell adhesion during blood vessel formation in mice.
abstract: The Rho family of small GTPases has been shown to be required in endothelial cells (ECs) during blood vessel formation. However, the underlying cellular events controlled by different GTPases remain unclear. Here, we assess the cellular mechanisms by which Cdc42 regulates mammalian vascular morphogenesis and maintenance. In vivo deletion of Cdc42 in embryonic ECs (Cdc42(Tie2KO)) results in blocked lumen formation and endothelial tearing, leading to lethality of mutant embryos by E9-10 due to failed blood circulation. Similarly, inducible deletion of Cdc42 (Cdc42(Cad5KO)) at mid-gestation blocks angiogenic tubulogenesis. By contrast, deletion of Cdc42 in postnatal retinal vessels leads to aberrant vascular remodeling and sprouting, as well as markedly reduced filopodia formation. We find that Cdc42 is essential for organization of EC adhesion, as its loss results in disorganized cell-cell junctions and reduced focal adhesions. Endothelial polarity is also rapidly lost upon Cdc42 deletion, as seen by failed localization of apical podocalyxin (PODXL) and basal actin. We link observed failures to a defect in F-actin organization, both in vitro and in vivo, which secondarily impairs EC adhesion and polarity. We also identify Cdc42 effectors Pak2/4 and N-WASP, as well as the actomyosin machinery, to be crucial for EC actin organization. This work supports the notion of Cdc42 as a central regulator of the cellular machinery in ECs that drives blood vessel formation.
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Barry
authors.affiliation: Department SCRB, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, 2000 Percival Stern Hall, New Orleans, LA 70118, USA.
authors.forename: Stryder M
authors.initials: SM
authors.lastname: Meadows
authors.affiliation: Division of Experimental Hematology and Cancer Biology, Children's Hospital Research Foundation, University of Cincinnati, Cincinnati, OH 45229, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
authors.forename: Pieter R
authors.initials: PR
authors.lastname: Norden
authors.affiliation: Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, USA.
authors.forename: George E
authors.initials: GE
authors.lastname: Davis
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA ondine.cleaver@utsouthwestern.edu.
authors.forename: Ondine
authors.initials: O
authors.lastname: Cleaver
mesh_terms: D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000378:metabolism; D017209:Apoptosis; D001808:Blood Vessels / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D002448:Cell Adhesion; D016764:Cell Polarity; D049109:Cell Proliferation; D002470:Cell Survival; D003599:Cytoskeleton / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D019426:Integrases / Q000378:metabolism; D018345:Mice, Knockout; D008954:Models, Biological; D018919:Neovascularization, Physiologic; D011247:Pregnancy; D011554:Pseudopodia / Q000378:metabolism; D042787:Receptor, TIE-2 / Q000378:metabolism; D012171:Retinal Vessels / Q000196:embryology / Q000378:metabolism; D015017:Yolk Sac / Q000098:blood supply / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000199:Actins; D000205:Actomyosin; D042787:Receptor, TIE-2; C079086:Tek protein, mouse; C045073:Cre recombinase; D019426:Integrases; D020764:cdc42 GTP-Binding Protein
keywords: Blood vessel development; Cdc42; F-actin; Filopodia; VE-cadherin; Vasculogenesis