Yap1 promotes sprouting and proliferation of lymphatic progenitors downstream of Vegfc in the zebrafish trunk
ELIFE
Authors: Grimm, Lin; Nakajima, Hiroyuki; Chaudhury, Smrita; Bower, Neil, I; Okuda, Kazuhide S.; Cox, Andrew G.; Harvey, Natasha L.; Koltowska, Katarzyna; Mochizuki, Naoki; Hogan, Benjamin M.
Abstract
Lymphatic vascular development involves specification of lymphatic endothelial progenitors that subsequently undergo sprouting, proliferation and tissue growth to form a complex second vasculature. The Hippo pathway and effectors Yap and Taz control organ growth and regulate morphogenesis and cellular proliferation. Yap and Taz control angiogenesis but a role in lymphangiogenesis remains to be fully elucidated. Here we show that YAP displays dynamic changes in lymphatic progenitors and Yap1 is essential for lymphatic vascular development in zebrafish. Maternal and Zygotic (MZ) yap1 mutants show normal specification of lymphatic progenitors, abnormal cellular sprouting and reduced numbers of lymphatic progenitors emerging from the cardinal vein during lymphangiogenesis. Furthermore, Yap1 is indispensable for Vegfc-induced proliferation in a transgenic model of Vegfc overexpression. Paracrine Vegfc-signalling ultimately increases nuclear YAP in lymphatic progenitors to control lymphatic development. We thus identify a role for Yap in lymphangiogenesis, acting downstream of Vegfc to promote expansion of this vascular lineage.
Myxoid liposarcoma: it's a hippo's world
EMBO MOLECULAR MEDICINE
Authors: Regina, Carla; Hettmer, Simone
Abstract
Fused in sarcoma: DNA damage-inducible transcript 3 protein (FUS:DDIT3) is a chimeric fusion oncoprotein present in 90% of human myxoid liposarcomas (MLS). The study by Trautmann et al in this issue of EMBO Molecular Medicine utilizes a drop-out RNAi screen to establish hyperactive Yes-associated protein 1 (YAP1), a major downstream nuclear effector of the Hippo signaling pathway, as a selectively essential transcript promoting viability and growth of MLS. These observations add to a growing body of evidence underscoring the importance of dysregulation of Hippo signaling in soft-tissue sarcomas expressing fusion oncoproteins and identify a novel target for therapeutic intervention in MLS. Comprehensive molecular characterization pipelines are needed to screen patients with advanced soft-tissue sarcomas for the presence of druggable alterations, including but not limited to nuclear YAP1 expression in MLS, to facilitate treatment decisions and advance therapy.