Delta-like ligand 4 regulates vascular endothelial growth factor receptor 2-driven luteal angiogenesis through induction of a tip/stalk phenotype in proliferating endothelial cells.
OBJECTIVE
To explore whether the Dll4/Notch-1 signaling pathway modulates vascular endothelial growth factor (VEGF)-dependent luteal angiogenesis and related function, by inducing a tip/stalk phenotype in endothelial cells (ECs).


METHODS
Experimental laboratory animal study.


METHODS
University-affiliated infertility center.


METHODS
Immature female mice.


METHODS
The presence of leading tip ECs in growing luteal vessel was identified by immunofluorescent analysis of Dll4 in the ovaries of hormonally stimulated female mice. The effects of Dll4 inhibition on luteal vessels functionality and related corpus luteum function were assessed by administering a Dll4 blocking antibody or placebo to hormonally stimulated female mice.


METHODS
Alteration of the tip/stalk phenotype was identified by immunofluorescence analysis of luteal vascular density, Dll4, Notch-1, and VEGF receptor 2 expression. Lectin perfusion was used to assay blood vessel functionality, whereas apoptosis and P levels were quantified to determine the effects on luteal function.


RESULTS
Expression of Dll4 was restricted to the tip of growing vessels. Inhibition of Dll4 signaling promotes promiscuous Dll4 expression, leading to increased, but paradoxically, nonfunctional vascularization, which was associated with decreased P levels.


CONCLUSIONS
The Dll4/Notch-1 signaling pathway has a modulatory role in VEGF-dependent luteal angiogenesis and related function through induction of a tip/stalk phenotype.
Fundación IVI, Instituto Universitario IVI/INCLIVA, Valencia, Spain.
Carmen M
CM
García-Pascual
Ralf C
RC
Zimmermann
Hortensia
H
Ferrero
Carrie J
CJ
Shawber
Jan
J
Kitajewski
Carlos
C
Simón
Antonio
A
Pellicer
Raúl
R
Gómez
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002135:Calcium-Binding Proteins; D049109:Cell Proliferation; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000166:cytology* / Q000502:physiology*; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D005260:Female; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009024:Morphogenesis / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010641:Phenotype; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C519665:DLL4 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C497762:Notch1 protein, mouse; D051881:Receptor, Notch1; D040301:Vascular Endothelial Growth Factor Receptor-2
Corpus luteum; Dll4/Notch-1 pathway; angiogenesis; vessel functionality