A cellular and molecular perspective on organotypic lymphatic (dys)function

The lymphatic vascular system maintains fluid homeostasis, allows uptake of dietary lipids, and serves as a conduit for immune cell trafficking. Functional aspects of the lymphatic vasculature are governed by specific features of lymphatic endothelial cells that line these vessels. Dysfunction of lymphatic endothelial cells can result in various consequences at the organ and at the systemic level including lymphedema formation. In this review, we explore the underlying molecular mechanisms and signaling cascades that drive lymphatic development and vessel formation. We discuss human genetic disorders that lead to primary lymphedema and corresponding in vivo disease models that have helped to expand our molecular understanding pertaining to the signaling cascades governing lymphatic vessel development and maturation, in particular the VEGFC/VEGFR3 and ANG/TIE signaling axes. Furthermore, we highlight recent advancements regarding the anatomy and function of meningeal lymphatics and the Schlemm's canal in the context of development and disease.