Distinct vascular endothelial growth factor signals for lymphatic vessel enlargement and sprouting

M Wirzenius, T Tammela, M Uutela, Y He… - The Journal of …, 2007 - rupress.org
M Wirzenius, T Tammela, M Uutela, Y He, T Odorisio, G Zambruno, JA Nagy, HF Dvorak…
The Journal of experimental medicine, 2007rupress.org
Lymphatic vessel growth, or lymphangiogenesis, is regulated by vascular endothelial growth
factor-C (VEGF-C) and-D via VEGF receptor 3 (VEGFR-3). Recent studies suggest that
VEGF, which does not bind to VEGFR-3, can also induce lymphangiogenesis through
unknown mechanisms. To dissect the receptor pathway that triggers VEGFR-3–independent
lymphangiogenesis, we used both transgenic and adenoviral overexpression of placenta
growth factor (PlGF) and VEGF-E, which are specific activators of VEGFR-1 and-2 …
Lymphatic vessel growth, or lymphangiogenesis, is regulated by vascular endothelial growth factor-C (VEGF-C) and -D via VEGF receptor 3 (VEGFR-3). Recent studies suggest that VEGF, which does not bind to VEGFR-3, can also induce lymphangiogenesis through unknown mechanisms. To dissect the receptor pathway that triggers VEGFR-3–independent lymphangiogenesis, we used both transgenic and adenoviral overexpression of placenta growth factor (PlGF) and VEGF-E, which are specific activators of VEGFR-1 and -2, respectively. Unlike PlGF, VEGF-E induced circumferential lymphatic vessel hyperplasia, but essentially no new vessel sprouting, when transduced into mouse skin via adenoviral vectors. This effect was not inhibited by blocking VEGF-C and -D. Postnatal lymphatic hyperplasia, without increased density of lymphatic vessels, was also detected in transgenic mice expressing VEGF-E in the skin, but not in mice expressing PlGF. Surprisingly, VEGF-E induced lymphatic hyperplasia postnatally, and it did not rescue the loss of lymphatic vessels in transgenic embryos where VEGF-C and VEGF-D were blocked. Our data suggests that VEGFR-2 signals promote lymphatic vessel enlargement, but unlike in the blood vessels, are not involved in vessel sprouting to generate new lymphatic vessels in vivo.
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