title: Dll4-containing exosomes induce capillary sprout retraction in a 3D microenvironment.
abstract: Delta-like 4 (Dll4), a membrane-bound Notch ligand, plays a fundamental role in vascular development and angiogenesis. Dll4 is highly expressed in capillary endothelial tip cells and is involved in suppressing neighboring stalk cells to become tip cells during angiogenesis. Dll4-Notch signaling is mediated either by direct cell-cell contact or by Dll4-containing exosomes from a distance. However, whether Dll4-containing exosomes influence tip cells of existing capillaries is unknown. Using a 3D microfluidic device and time-lapse confocal microscopy, we show here for the first time that Dll4-containing exosomes causes tip cells to lose their filopodia and trigger capillary sprout retraction in collagen matrix. We demonstrate that Dll4 exosomes can freely travel through 3D collagen matrix and transfer Dll4 protein to distant tip cells. Upon reaching endothelial sprout, it causes filopodia and tip cell retraction. Continuous application of Dll4 exosomes from a distance lead to significant reduction of sprout formation. This effect correlates with Notch signaling activation upon Dll4-containing exosome interaction with recipient endothelial cells. Furthermore, we show that Dll4-containing exosomes increase endothelial cell motility while suppressing their proliferation. These data revealed novel functions of Dll4 in angiogenesis through exosomes.
authors: Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics Inter-Disciplinary Research programme, 1 CREATE Way, #04-13/14 Enterprise Wing, Singapore 138602.
authors: Soheila
authors: S
authors: Sharghi-Namini
authors: 1] Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics Inter-Disciplinary Research programme, 1 CREATE Way, #04-13/14 Enterprise Wing, Singapore 138602 [2] Department of Biological Sciences, National University of Singapore, Singapore 117543.
authors: Evan
authors: E
authors: Tan
authors: Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics Inter-Disciplinary Research programme, 1 CREATE Way, #04-13/14 Enterprise Wing, Singapore 138602.
authors: Lee-Ling Sharon
authors: LL
authors: Ong
authors: Department of Biological Sciences, National University of Singapore, Singapore 117543.
authors: Ruowen
authors: R
authors: Ge
authors: 1] Singapore-MIT Alliance for Research and Technology, BioSystems and Micromechanics Inter-Disciplinary Research programme, 1 CREATE Way, #04-13/14 Enterprise Wing, Singapore 138602 [2] d'Arbeloff Laboratory for Information Systems and Technology, Massachusetts Institute of Technology, Cambridge MA 02139-4307, USA.
authors: H Harry
authors: HH
authors: Asada
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D002196:Capillaries / Q000254:growth & development*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000378:metabolism*; D046210:Microfluidic Analytical Techniques; D046529:Microscopy, Electron, Transmission; D018919:Neovascularization, Physiologic; D011554:Pseudopodia / Q000378:metabolism; D051880:Receptors, Notch / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D051880:Receptors, Notch; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C000588866:KDR protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2