Slc39a5-mediated zinc homeostasis plays an essential role in venous angiogenesis in zebrafish.

Zhidan Xia,Fudi Wang,Junxia Min,Xuyan He,Wei Dai,Lu Zhao,Xinying Bi,Jia Lian

doi:10.1098/rsob.200281

Abstract

Angiogenesis is a precise process mediated by a variety of signals and the environmental niche. Although the essential trace element zinc and its homeostasis are essential for maintaining proper cellular functions, whether zinc plays a role in angiogenesis is currently unknown. Using zebrafish embryos as a model system, we found that zinc treatment significantly increased the expression of the slc39a5 gene, which encodes the zinc transporter Slc39a5. Moreover, knocking down slc39a5 expression using either a morpholino or CRISPR/Cas9-mediated gene editing led to cardiac ischaemia and an accumulation of red blood cells in the caudal vein plexus (CVP), as well as delayed venous sprouting and fewer vascular loops in the CVP region during early development. Further analysis revealed significantly reduced proliferation and delayed cell migration in the caudal vein of slc39a5 morphants. At the mechanistic level, we found increased levels of systemic zinc in slc39a5-deficient embryos, and chelating zinc restored CVP development. In addition, we found that zinc overload in wild-type embryos leads to impaired CVP formation. Taken together, these results indicate that Slc39a5 plays a critical role in endothelial sprouting and migration in venous angiogenesis by regulating zinc homeostasis.

Highlights

Angiogenesis is an essential biological process in which new blood vessels emanate from existing vascular structures, with vascular budding, migration, proliferation and pruning, thereby establishing the vascular network [1,2]
Using whole-mount in situ hybridization, we found that slc39a5 is expressed uniformly through WT zebrafish embryos at 1–2 days post-fertilization, and its expression becomes concentrated at the head and gut region by 3 dpf
Similar to angiogenesis in the caudal vein plexus (CVP) region, we found that endothelial sprouting was significantly delayed in the sub-intestinal vein plexus (SIVP) in slc39a5 morphants, suggesting that the delayed venous angiogenesis in slc39a5 morphants is a general phenomenon

Summary

Introduction

Angiogenesis is an essential biological process in which new blood vessels emanate from existing vascular structures, with vascular budding, migration, proliferation and pruning, thereby establishing the vascular network [1,2]. The dorsal aorta and axial vein form a primitive circulatory loop, and angiogenesis from these vessels plays a key role in generating complex vascular networks. Angiogenesis is necessary for the efficient delivery of oxygen and plays a critical role in a wide range of physiological and pathophysiological processes, including tissue development, nutrient transport, wound healing and tumour neovascularization [3,4,5]. As an essential trace element, zinc is important for maintaining cellular physiology and for the development of various organs and tissues [6,7,8]. Zinc homeostasis is controlled by two families of transporter proteins, including 14 members of the SLC39A (Zrt- and Irt-like protein, ZIP) family and 10 members of the SLC30A (zinc efflux transporter, ZnT) family [9,10]. Whether other members of the SLC39A family play role in vascular development is an open question

Methods

Results

Conclusion