Increased ischemia-induced angiogenesis in the staggerer mouse, a mutant of the nuclear receptor Roralpha.
Ror alpha is an orphan nuclear receptor. In homozygous staggerer mutant mice (Ror alpha(sg/sg)), a deletion within the Ror alpha gene leads to an overexpression of inflammatory cytokines. Because inflammation and hypoxia are 2 key stimuli of ischemia-induced angiogenesis, we studied the role of Ror alpha in this setting. Ischemia was induced by ligation of the right femoral artery in C57BL/6 Ror alpha(+/+) and Ror alpha(sg/sg) mice. After 3 and 28 days, angiogenesis was evaluated by microangiography, measurement of capillary density using immunohistochemistry (anti-CD31), and measurement of blood flow by laser Doppler imaging. At day 3, angiographic score and blood flow were similar in Ror alpha(sg/sg) mice and in Ror alpha(+/+) littermates. Conversely, at day 28, Ror alpha(sg/sg) mice showed a significant 2-fold increase in angiographic score and a 3-fold increase in capillary density within the ischemic hindlimb compared with control. Functionally, this coincided with a significant rise in leg perfusion in Ror alpha(sg/sg) mice (0.83+/-0.05 for ischemic/nonischemic leg perfusion ratio) compared with Ror(+/+) mice (0.66+/-0.04, P<0.05). In addition, more extensive angiogenesis in Ror alpha(sg/sg) mice correlated with an increased expression of eNOS protein by 83+/-12% and 71+/-24% at 3 and 28 days, respectively (P<0.05), whereas the level of the antiangiogenic cytokine IL-12 was significantly reduced by 38+/-10% at day 28 (P<0.05). Conversely, no changes in VEGF expression were observed. Our study identifies for the first time a new role for Ror alpha as a potent negative regulator of ischemia-induced angiogenesis.
Besnard
S
S
INSERM U541, Hôpital Lariboisière, and IFR Circulation-Paris 7, Université Paris 7-Denis Diderot, France.
Silvestre
J S
JS
Duriez
M
M
Bakouche
J
J
Lemaigre-Dubreuil
Y
Y
Mariani
J
J
Levy
B I
BI
Tedgui
A
A
D000818:Animals; D001160:Arterioles / Q000166:cytology; D001783:Blood Flow Velocity / Q000502:physiology; D015153:Blotting, Western; D002196:Capillaries / Q000166:cytology; D016228:Endothelial Growth Factors / Q000378:metabolism; D005263:Femoral Artery / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply; D018664:Interleukin-12 / Q000378:metabolism; D007511:Ischemia / Q000378:metabolism*; D017078:Laser-Doppler Flowmetry; D008026:Ligation; D008222:Lymphokines / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D008833:Microcirculation / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D015534:Trans-Activators / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D018664:Interleukin-12; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse