Stabilin 1 and 2 are important regulators for cellular uptake of apolipoprotein B-containing lipoproteins in zebrafish

Robin A.F Verwilligen,Lindsay Mulder,Frans J Rodenburg,Amy Van Dijke,Menno Hoekstra,Jeroen Bussmann,Miranda Van Eck

doi:10.1016/j.atherosclerosis.2022.02.018

Robin A.F Verwilligen, Lindsay Mulder + Show 5 more

Open Access

https://doi.org/10.1016/j.atherosclerosis.2022.02.018

Copy DOI

Abstract

Background and aimsScavenger receptors form a superfamily of membrane-bound receptors that bind and internalize different types of ligands, including pro-atherogenic oxidized low-density lipoproteins (oxLDLs). In vitro studies have indicated a role for the liver sinusoidal endothelial cell receptors stabilin 1 (stab1) and 2 (stab2) in oxLDL clearance. In this study, we evaluated the potential role of stab1 and stab2 in lipoprotein uptake in zebrafish, an upcoming model for studying cholesterol metabolism and atherosclerosis. MethodsLipoproteins were injected in the duct of Cuvier of wild-type (ABTL) or stab1 and stab2 mutant (stab1−/−stab2−/−) zebrafish larvae at 3 days post-fertilization. To examine the effect of stabilin deficiency on lipoprotein and cholesterol metabolism, zebrafish larvae were challenged with a high cholesterol diet (HCD; 4% w/w) for 10 days. ResultsLipoprotein injections showed impaired uptake of both LDL and oxLDL into the vessel wall of caudal veins of stab1−/−stab2−/− zebrafish, which was paralleled by redistribution to tissue macrophages. Total body cholesterol levels did not differ between HCD-fed stab1−/−stab2−/− and ABTL zebrafish. However, stab1−/−stab2−/− larvae exhibited 1.4-fold higher mRNA expression levels of ldlra involved in (modified) LDL uptake, whereas the expression levels of scavenger receptors scarb1 and cd36 were significantly decreased. ConclusionsWe have shown that stabilins 1 and 2 have an important scavenging function for apolipoprotein B-containing lipoproteins in zebrafish and that combined deficiency of these two proteins strongly upregulates the clearance of lipoproteins by macrophages within the caudal vein. Our current study highlights the use of zebrafish as model to study lipoprotein metabolism and liver sinusoidal endothelial cell function.

Highlights

Atherosclerosis is a complex disease in which the recruitment and accumulation of serum lipoproteins in the arterial wall, where they are subjected to oxidation, induce a chronic pro-inflammatory cascade leading to endothelial dysfunction and plaque development.Establishing adequate atherosclerosis animal models is pivotal for studying the complex etiology and progression of the disease, as well as for screening of novel therapeutic targets
We examined the role of stabilins in the clearance of lipoproteins and early atherogenesis using a zebrafish model
Considering its many advantages and its highly conserved lipid meta bolism, the zebrafish has been proposed as an upcoming alternative animal model to study the processes involved in atherogenesis, including lipoprotein uptake, endothelial function, and macrophage foam cell formation which is the hallmark of early atherogenesis

Summary

Introduction

Atherosclerosis is a complex disease in which the recruitment and accumulation of serum lipoproteins in the arterial wall, where they are subjected to oxidation, induce a chronic pro-inflammatory cascade leading to endothelial dysfunction and plaque development.Establishing adequate atherosclerosis animal models is pivotal for studying the complex etiology and progression of the disease, as well as for screening of novel therapeutic targets. Several studies have shown that wild-type zebrafish larvae are susceptible to high cholesterol diet (HCD) induced atherosclerosis [2,3]. The exact mech anisms underlying the pro-atherogenic effects observed in wild-type zebrafish larvae, are yet unknown. This is rele vant as our recent study showed that wild-type zebrafish are rather protected against the accumulation of macrophage foam cells and early atherosclerosis [4]. We evaluated the potential role of stab and stab in lipoprotein uptake in zebrafish, an upcoming model for studying cholesterol metabolism and atherosclerosis. To examine the effect of stabilin deficiency on lipoprotein and cholesterol metabolism, zebrafish larvae were challenged with a high cholesterol diet (HCD; 4% w/w) for 10 days. Our current study highlights the use of zebrafish as model to study lipoprotein metabolism and liver sinusoidal endothelial cell function

Methods

Results

Conclusion