VEGFC/FLT4-induced cell-cycle arrest mediates sprouting and differentiation of venous and lymphatic endothelial cells

Summary The formation of new vessels requires a tight synchronization between proliferation, differentiation, and sprouting. However, how these processes are differentially activated, often by neighboring endothelial cells (ECs), remains unclear. Here, we identify cell cycle progression as a regulator of EC sprouting and differentiation. Using transgenic zebrafish illuminating cell cycle stages, we show that venous and lymphatic precursors sprout from the cardinal vein exclusively in G1 and reveal that cell-cycle arrest is induced in these ECs by overexpression of p53 and the cyclin-dependent kinase (CDK) inhibitors p27 and p21. We further demonstrate that, in vivo, forcing G1 cell-cycle arrest results in enhanced vascular sprouting. Mechanistically, we identify the mitogenic VEGFC/VEGFR3/ERK axis as a direct inducer of cell-cycle arrest in ECs and characterize the cascade of events that render “sprouting-competent” ECs. Overall, our results uncover a mechanism whereby mitogen-controlled cell-cycle arrest boosts sprouting, raising important questions about the use of cell cycle inhibitors in pathological angiogenesis and lymphangiogenesis.
Graphical abstract
Highlights • Endothelial cells sprout from the PCV in G1 phase of the cell cycle • VEGFC/FLT4/ERK induce p53-, p21-, and p27-mediated cell-cycle arrest to enable sprouting • Forced G1 cell-cycle arrest results in ectopic sprouting of undifferentiated ECs
Jerafi-Vider et al. report a mechanism of endothelial cell sprouting, whereby the mitogenic VEGFC/FLT4/ERK signaling pathway induces p53-, p21-, and p27-mediated cell-cycle arrest, conferring angiogenic potential. These findings have important implications for the putative short-term effects of using cell cycle inhibitors in settings of pathological angiogenesis and lymphangiogenesis.