Zebrafish models of human liver development and disease

Abstract

The liver performs a large number of essential synthetic and regulatory functions that are acquired during fetal development and persist throughout life. Their disruption underlies a diverse group of heritable and acquired diseases that affect both pediatric and adult patients. Although experimental analyses used to study liver development and disease are typically performed in cell culture models or rodents, the zebrafish is increasingly used to complement discoveries made in these systems. Forward and reverse genetic analyses over the past two decades have shown that the molecular program for liver development is largely conserved between zebrafish and mammals, and that the zebrafish can be used to model heritable human liver disorders. Recent work has demonstrated that zebrafish can also be used to study the mechanistic basis of acquired liver diseases. Here, we provide a comprehensive summary of how the zebrafish has contributed to our understanding of human liver development and disease.

Figure 1

Brightfield images (A, C, and E) and corresponding whole-mount fluorescent images (B, D, and F) of live Tg(L-FABP-dsRed) embryos and larvae, demonstrating liver growth between 2 dpf and 5 dpf.

Figure 2

Overview of zebrafish biliary development and function. (A) Brightfield high-magnification image of a live 5 dpfTg(bglob-EGFP)larva, raised in 1-phenyl-2-thiourea (PTU) to inhibit melanophore development. Liver (red dashed line) is anterior to intestinal bulb and swim bladder. (B) The same larva imaged by whole-mount fluorescence microscopy. Developing biliary cells in the liver express the Notch-responsive reporter gene encoding EGFP. (C) Confocal projection of fixed wild-type liver, stained with monoclonal antibody 2F11 to visualize biliary tree, including gallbladder (arrowhead) and extrahepatic bile duct (arrow). (D–F) High-magnification confocal projection through the liver of a 5 dpf wild-type larvae immunstained with the 2F11 antibody showing the relationship between bile ducts (labeled by 2F11) and canaliculi (labeled by anti-Mdr antibody). (G) Brightfield image of live 5 dpf wild-type larva in right lateral view, showing right liver lobe, gallbladder, and pancreas. (H) Whole-mount fluorescent image of the same larva, two hours following application of BODIPY-FL C16 to the aqueous media. Fluorescent lipid is secreted into bile and accumulated in the gallbladder.