Adrenomedullin signaling is necessary for murine lymphatic vascular development
J. Clin. Invest. Kimberly L. Fritz-Six, et al. 118:40 doi:10.1172/JCI33302 [
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Figure 7AM signaling is required for the proliferation and growth of jugular lymphatic vessels during embryonic development. (
A–
C) The percentage of proliferating cells relative to total cells was determined in the jugular vein and neighboring jugular lymph sac of wild-type (gray bars) and
calcrl–/–,
AM–/–, and
RAMP2–/– (black bars,
A–
C, respectively) littermate embryos. Percent proliferative cells was defined as the number of BrdU-positive endothelial cells divided by the total number of endothelial cells in each vessel. Error bars indicate SEM. *
P = 0.01 for
calcrl–/– (
A),
P = 0.004 for
AM–/– (
B), and
P = 0.01 for
RAMP2–/– (
C); Student’s
t test.
n > 6 animals per genotype. (
D and
E) Whole mount immunofluorescence of developing vasculature identified by PECAM staining and visualized by 3D OPT of wild-type (
D) and
RAMP2–/– (
E) littermate embryos at E13.5. (
F and
G) Whole mount immunofluorescence of developing lymphatic vasculature identified by VEGFR3 staining and visualized by 3D OPT of wild-type (
F) and
RAMP2–/– (
G) littermate embryos at E14.5. Compare the presence of well-formed jugular lymph sacs in the wild-type embryo (yellow arrows in
F) with the relative lack of jugular lymphatic vessels in the
RAMP2–/– littermate (
G). Note that the retroperitoneal lymph vessel (red arrows) and dermal lymphatic vessels (green asterisks) of
RAMP2–/– mice appear normal compared with those of wild-type embryos. Three embryos from 2 different litters were stained for PECAM and VEGFR3. The online supplemental data contains movies for enhanced, high-resolution, 3D viewing (Supplemental Figures 4 and 5). Scale bar: 2,000 μM.
