title: RhoA-mediated signaling in Notch-induced senescence-like growth arrest and endothelial barrier dysfunction.
abstract: OBJECTIVE
  Notch signaling has a critical role in vascular development and morphogenesis. Activation of Notch in endothelial cells led to a senescence-like phenotype with loss of barrier function. Our objective was to understand the molecular pathways mediating this phenotype.
  
  
  RESULTS
  Human primary endothelial cells increase expression of Notch receptors and ligands during propagation in vitro toward natural senescence. This senescence was induced at low passage with Notch activation. We characterized the pathways activated downstream of Notch signaling. Notch was activated by Delta-like 4 ligand or constitutively active Notch receptors and measured for cell proliferation, migration, and sprouting. Notch signaling triggered early senescence in low-passage cells, characterized by increased p53 and p21 expression. The senescence phenotype was associated with hyperpermeability of the monolayer, with disrupted vascular endothelial cadherin and β-catenin levels and localization. Consistent with changes in cell shape and contact, we demonstrated that Notch activation increases myosin light chain phosphorylation by activating Rho kinase. Inhibition of Rho abrogated Notch-induced myosin light chain phosphorylation and led to enhanced barrier function by reorganizing F-actin to β-catenin-containing cell-cell adherens junctions.
  
  
  CONCLUSIONS
  Our findings show that RhoA/Rho kinase regulation by Notch signaling in endothelial cells triggers a senescence phenotype associated with endothelial barrier dysfunction.
authors.affiliation: Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME 04074, USA.
authors.forename: Deepak
authors.initials: D
authors.lastname: Venkatesh
authors.forename: Natalie
authors.initials: N
authors.lastname: Fredette
authors.forename: Bahman
authors.initials: B
authors.lastname: Rostama
authors.forename: Yuefeng
authors.initials: Y
authors.lastname: Tang
authors.forename: Calvin P H
authors.initials: CP
authors.lastname: Vary
authors.forename: Lucy
authors.initials: L
authors.lastname: Liaw
authors.forename: Sumithra
authors.initials: S
authors.lastname: Urs
mesh_terms: D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002465:Cell Movement; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000187:drug effects; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018994:Myosin Light Chains / Q000378:metabolism; D018919:Neovascularization, Physiologic; D010539:Permeability; D010641:Phenotype; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051881:Receptor, Notch1 / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D000099152:Cadherin 5
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D015820:Cadherins; D002135:Calcium-Binding Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D036341:Intercellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D018994:Myosin Light Chains; D047428:Protein Kinase Inhibitors; D051881:Receptor, Notch1; D051880:Receptors, Notch; D016159:Tumor Suppressor Protein p53; D051176:beta Catenin; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; D000099152:Cadherin 5; C493956:CDKN1A protein, human; C495270:CTNNB1 protein, human; C424126:DLL4 protein, human; C497762:Notch1 protein, mouse; C495901:TP53 protein, human; C066737:RHOA protein, human