[HTML][HTML] Pericyte-expressed Tie2 controls angiogenesis and vessel maturation

M Teichert, L Milde, A Holm, L Stanicek… - Nature …, 2017 - nature.com
M Teichert, L Milde, A Holm, L Stanicek, N Gengenbacher, S Savant, T Ruckdeschel…
Nature communications, 2017nature.com
The Tie receptors with their Angiopoietin ligands act as regulators of angiogenesis and
vessel maturation. Tie2 exerts its functions through its supposed endothelial-specific
expression. Yet, Tie2 is also expressed at lower levels by pericytes and it has not been
unravelled through which mechanisms pericyte Angiopoietin/Tie signalling affects
angiogenesis. Here we show that human and murine pericytes express functional Tie2
receptor. Silencing of Tie2 in pericytes results in a pro-migratory phenotype. Pericyte Tie2 …
Abstract
The Tie receptors with their Angiopoietin ligands act as regulators of angiogenesis and vessel maturation. Tie2 exerts its functions through its supposed endothelial-specific expression. Yet, Tie2 is also expressed at lower levels by pericytes and it has not been unravelled through which mechanisms pericyte Angiopoietin/Tie signalling affects angiogenesis. Here we show that human and murine pericytes express functional Tie2 receptor. Silencing of Tie2 in pericytes results in a pro-migratory phenotype. Pericyte Tie2 controls sprouting angiogenesis in in vitro sprouting and in vivo spheroid assays. Tie2 downstream signalling in pericytes involves Calpain, Akt and FOXO3A. Ng2-Cre-driven deletion of pericyte-expressed Tie2 in mice transiently delays postnatal retinal angiogenesis. Yet, Tie2 deletion in pericytes results in a pronounced pro-angiogenic effect leading to enhanced tumour growth. Together, the data expand and revise the current concepts on vascular Angiopoietin/Tie signalling and propose a bidirectional, reciprocal EC-pericyte model of Tie2 signalling.
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