Vegfd modulates both angiogenesis and lymphangiogenesis during zebrafish embryonic development

Abstract

Vascular endothelial growth factors (VEGFs) control angiogenesis and lymphangiogenesis during development and in pathological conditions. In the zebrafish trunk, Vegfa controls the formation of intersegmental arteries by primary angiogenesis and Vegfc is essential for secondary angiogenesis, giving rise to veins and lymphatics. Vegfd has been largely thought of as dispensable for vascular development in vertebrates. Here, we generated a zebrafish vegfd mutant by genome editing. vegfd mutants display significant defects in facial lymphangiogenesis independent of vegfc function. Strikingly, we find that vegfc and vegfd cooperatively control lymphangiogenesis throughout the embryo, including during the formation of the trunk lymphatic vasculature. Interestingly, we find that vegfd and vegfc also redundantly drive artery hyperbranching phenotypes observed upon depletion of Flt1 or Dll4. Epistasis and biochemical binding assays suggest that, during primary angiogenesis, Vegfd influences these phenotypes through Kdr (Vegfr2) rather than Flt4 (Vegfr3). These data demonstrate that, rather than being dispensable during development, Vegfd plays context-specific indispensable and also compensatory roles during both blood vessel angiogenesis and lymphangiogenesis.

Vascular endothelial growth factor signaling in development and disease

“…The N-terminal cleavage that then results in full activity of VEGFC is regulated by collagen-and calcium-binding EGF domains 1 (CCBE1) protein and executed by a disintegrin and metalloprotease with thrombospondin motifs-3 (ADAMTS3) protease (Jeltsch et al, 2014;Le Guen et al, 2014;Roukens et al, 2015). Specific proteases that activate VEGFD by cleavage of the N-terminal propeptide are so far unknown, suggesting that VEGFD has evolved to function in distinct angiogenic and lymphangiogenic responses (Bower et al, 2017;Bui et al, 2016;McColl et al, 2003).…”

“…VEGFA, in addition to inducing angiogenesis, can also stimulate lymphatic vessel expansion (Nagy et al, 2002;Wirzenius et al, 2007). Despite its similarity to VEGFC, VEGFD is dispensable for developmental lymphangiogenesis in mammals (Baldwin et al, 2005), although its absence leads to somewhat decreased lymphatic vessel caliber in the skin (Paquet-Fifield et al, 2013) and inhibition of facial lymphangiogenesis in zebrafish (Bower et al, 2017).…”

Evolutionary Differences in the Vegf/Vegfr Code Reveal Organotypic Roles for the Endothelial Cell Receptor Kdr in Developmental Lymphangiogenesis

“…In the craniofacial region of the embryo, LECs emerge from the common cardinal vein and fuse with LECs that emerge from the primary head sinus to form a complex facial lymphatic network; meanwhile, a population of mural LECs also forms around the brain (Astin et al, 2014;Bower et al, 2017a;Okuda et al, 2012;van Lessen et al, 2017;Venero Galanternik et al, 2017). Both vegfc and vegfd zebrafish mutants show reductions in, and double vegfc, vegfd mutants show major or complete loss of, craniofacial lymphatic development (Bower et al, 2017a(Bower et al, , 2017b. Zebrafish mutants lacking Flt4 (the homolog of human VEGFR3) show a complete block in trunk lymphangiogenesis and specification of trunk LECs (with no induction of the LEC transcription factor Prox1), but they do not display a complete loss of craniofacial lymphangiogenesis (Shin et al, 2016).…”

“…Zebrafish mutants lacking Flt4 (the homolog of human VEGFR3) show a complete block in trunk lymphangiogenesis and specification of trunk LECs (with no induction of the LEC transcription factor Prox1), but they do not display a complete loss of craniofacial lymphangiogenesis (Shin et al, 2016). We have previously shown that zebrafish Vegfd can bind Kdr but not Kdrl (Bower et al, 2017b); however, it was assumed that the contribution to facial lymphangiogenesis by zebrafish Vegfd occurs via activation of the lymphangiogenic zebrafish receptor Flt4.…”

VEGF-C et vaisseaux lymphatiques

“…Le rôle du VEGF-D est moins bien compris. Chez le poisson zèbre, il régule l'angiogenèse et la lymphangiogenèse au cours du développement [20]. Chez la souris, des expériences de double invalidation des gènes Vegfd et Sox18 suggèrent qu'ils contrôlent le développement vasculaire en modulant l'activité de SOX18 [21].…”