Valves Are a Conserved Feature of the Zebrafish Lymphatic System

Abstract

The lymphatic system comprises blind-ended tubes that collect interstitial fluid and return it to the circulatory system. In mammals, unidirectional lymphatic flow is driven by muscle contraction working in conjunction with valves. Accordingly, defective lymphatic valve morphogenesis results in backflow leading to edema. In fish species, studies dating to the 18 th century failed to identify lymphatic valves, a precedent that currently persists, raising the question of whether the zebrafish could be used to study the development of these structures. Here, we provide functional and morphological evidence of valves in the zebrafish lymphatic system. Electron microscopy revealed valve ultrastructure similar to mammals, while live imaging using transgenic lines identified the developmental origins of lymphatic valve progenitors. Zebrafish embryos bearing mutations in genes required for mammalian valve morphogenesis show defective lymphatic valve formation and edema. Together, our observations provide a foundation from which to further investigate lymphatic valve formation in zebrafish.

Endothelial Cell Dynamics in Vascular Development: Insights From Live-Imaging in Zebrafish

“…The formation of the craniofacial lymphatic vasculature occurs in a very different manner to lymphatics in other tissues and provides compelling evidence for heterogeneity in developmental and cellular processes ( Okuda et al, 2012 ; Astin et al, 2014 ; Shin et al, 2016b , 2019 ; Eng et al, 2019 ; Vogrin et al, 2019 ). For example, Eng and colleagues lineage traced cells that contribute to facial lymphatics using the photoconvertible Kaede protein.…”

Svep1 stabilizes developmental vascular anastomosis in reduced flow conditions

“…Svep1(also known as Polydom) is a secreted ECM protein that has been reported to mediate cell to substrate adhesion in vitro, at leasr in part in an integrin α9β1-dependent manner [13]. Although integrin α9 zebrafish mutants fail to display a vascular phenotype other than lymphatic valve formation [40], interaction with another member of the Integrin family could prove more relevant. For example, Integrin β1b appears to be important for the formation of the DLAV in zebrafish embryos [41].…”

Uptake of Nanotitania by Gingival Epithelial Cells Promotes Inflammatory Response and Is Accelerated by Porphyromonas gingivalis Lipopolysaccharide: An In Vitro Study

“…Scanning electron microscopy (SEM) evaluation was conducted as reported previously [ 49 ]. In brief, Ca9-22 cells were cultured in a cell culture insert at 37 °C in 5% CO 2 atmospheric air for 48 h. Then, the cells were incubated with nanotitania (10 or 100 µg/mL) for 1, 12 and 24 h. After the incubation, cells on the culture insert were washed three times with phosphate-buffered saline (PBS; Nacalai Tesque, Kyoto, Japan) and fixed with 2.5% glutaraldehyde for 1 h. After washing with PBS, the cells were post-fixed with 1% OsO 4 at 4 °C for 1 h. The cells were washed again three times with PBS and then dehydrated with 50%, 70%, 80% and 90% ethanol for 15 min each, and then the cells were washed with 100% ethanol four times for 15 min.…”