title: Delta-like 4 inhibits choroidal neovascularization despite opposing effects on vascular endothelium and macrophages.
abstract: Inflammatory neovascularization, such as choroidal neovascularization (CNV), occur in the presence of Notch expressing macrophages. DLL4s anti-angiogenic effect on endothelial cells (EC) has been widely recognized, but its influence on Notch signaling on macrophages and its overall effect in inflammatory neovascularization is not well understood. We identified macrophages and ECs as the main Notch 1 and Notch 4 expressing cells in CNV. A soluble fraction spanning Ser28-Pro525 of the murine extracellular DLL4 domain (sDLL4/28-525) activated the Notch pathway, as it induces Notch target genes in macrophages and ECs and inhibited EC proliferation and vascular sprouting in aortic rings. In contrast, sDLL4/28-525 increased pro-angiogenic VEGF, and IL-1β expression in macrophages responsible for increased vascular sprouting observed in aortic rings incubated in conditioned media from sDLL4/28-525 stimulated macrophages. In vivo, Dll4(+/-) mice developed significantly more CNV and sDLL4/28-525 injections inhibited CNV in Dll4(+/-) CD1 mice. Similarly, sDLL4/28-525 inhibited CNV in C57Bl6 and its effect was reversed by a γ-secretase inhibitor that blocks Notch signaling. The inhibition occurred despite increased VEGF, IL-1β expression in infiltrating inflammatory macrophages in sDLL4/28-525 treated mice and might be due to direct inhibition of EC proliferation in laser-induced CNV as demonstrated by EdU labelling in vivo. In conclusion, Notch activation on macrophages and ECs leads to opposing effects in inflammatory neovascularization in situations such as CNV.
authors.affiliation: Centre de Recherche des Cordeliers, INSERM, UMR S 872, 75006, Paris, France. sergecamelo2@hotmail.com
authors.forename: Serge
authors.initials: S
authors.lastname: Camelo
authors.forename: William
authors.initials: W
authors.lastname: Raoul
authors.forename: Sophie
authors.initials: S
authors.lastname: Lavalette
authors.forename: Bertrand
authors.initials: B
authors.lastname: Calippe
authors.forename: Brunella
authors.initials: B
authors.lastname: Cristofaro
authors.forename: Olivier
authors.initials: O
authors.lastname: Levy
authors.forename: Marianne
authors.initials: M
authors.lastname: Houssier
authors.forename: Eric
authors.initials: E
authors.lastname: Sulpice
authors.forename: Laurent
authors.initials: L
authors.lastname: Jonet
authors.forename: Christophe
authors.initials: C
authors.lastname: Klein
authors.forename: Estelle
authors.initials: E
authors.lastname: Devevre
authors.forename: Gilles
authors.initials: G
authors.lastname: Thuret
authors.forename: Antonio
authors.initials: A
authors.lastname: Duarte
authors.forename: Anne
authors.initials: A
authors.lastname: Eichmann
authors.forename: Laurence
authors.initials: L
authors.lastname: Leconte
authors.forename: Xavier
authors.initials: X
authors.lastname: Guillonneau
authors.forename: Florian
authors.initials: F
authors.lastname: Sennlaub
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002135:Calcium-Binding Proteins; D020256:Choroidal Neovascularization / Q000517:prevention & control*; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000503:physiopathology*; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D017931:DNA Primers; D036341:Intercellular Signaling Peptides and Proteins