Effects of calorie restriction on the zebrafish liver proteome

Abstract

A proteomic approach was taken to study how fish respond to changes in calorie availability, with the longer-term goal of understanding the evolution of lipid metabolism in vertebrates. Zebrafish (Danio rerio) were fed either high (3 rations/day) or low (1 ration/7 days) calorie diets for 5 weeks and liver proteins extracted for proteomic analyses. Proteins were separated on two-dimensional electrophoresis gels and homologous spots compared between treatments to determine which proteins were up-regulated with high-calorie diet. Fifty-five spots were excised from the gel and analyzed via LC–ESI MS/MS, which resulted in the identification of 69 unique proteins (via multiple peptides). Twenty-nine of these proteins were differentially expressed between treatments. Differentially expressed proteins were mapped to Gene Ontology (GO) terms, and these terms compared to the entire zebrafish GO annotation set by Fisher's exact test. The most significant GO terms associated with high-calorie diet are related to a decrease in oxygen-binding activity in the high-calorie treatment. This response is consistent with a well-characterized response in obese humans, indicating there may be a link between lipid storage and hypoxia sensitivity in vertebrates.

A reference growth curve for nutritional experiments in zebrafish (Danio rerio) and changes in whole body proteome during development

“…Thus, zebrafish proteomics would provide a new dimension in zebrafish research as it previously occurred when Martin et al (2001) pioneered the use of 2D-PAGE combined with peptide mass mapping by MALDI-TOF in rainbow trout (Oncorhynchus mykiss) to investigate for changes in the liver proteome between fed and fasted fish. Up to date, there have been several attempts to analyze zebrafish protein profiles by means of proteomics (e.g., Shrader et al 2003;Bosworth et al 2005;Goishi et al 2006;Link et al 2006a, b;Tay et al 2006;Lemeer et al 2007Lemeer et al , 2008Jury et al 2008;Lucitt et al 2008;Mendelsohn et al 2009), clearly showing that proteomic analysis of different stages of zebrafish development provides crucial information on proteins regulated on translational and posttranslational levels, which are not possible to detect by gene expression analysis. A recent review emphasized the importance of proteomic analysis in making zebrafish a complete vertebrate model toward comprehension of molecular, biochemical, and developmental processes (Love et al 2004).…”

“…This is a plasticity that cannot be fully understood by studying one or a few parameters at a time. For this reason, bi-dimensional proteomics has recently emerged as a tool for developing a broader understanding of the processes involved in the modulation of protein clusters in specific tissues or organs in response to given environmental or dietary stimuli (Martin et al 2001(Martin et al , 2003Shrader et al 2003;Vilhelmsson et al 2004;Jury et al 2008;BohneKjersem et al 2009;Mendelsohn et al 2009). Differential protein profile analysis can identify proteins that are up-or down-regulated under different experimental conditions, and this cluster analysis will be a characteristic of a certain proteomic phenotype.…”

Zebrafish Models of Human Liver Development and Disease

“…These changes are reversible by a 2 week period of calorie restriction, or treatment with extracts of selected foods (178). A separate overfeeding model used a proteomic approach to show decreased levels of oxygen binding proteins (including iron ion-binding proteins) in overfed fish, similar to a response seen in obese humans (89). A 3-week starvation model showed hepatic gene expression changes consistent with decreased metabolism and increased gluconeogenesis (36), while a separate fasting/refeeding model showed modulation of energy-responsive signaling intermediates and transcription factors similar to that seen in mammals (23).…”

Variation in gene expression along a salinity gradient in wild populations of the euryhaline black‐chinned tilapia Sarotherodon melanotheron

“…The ad libitum feeding during laboratory experiments (Tine et al , 2008) may have created fatter individuals, which were preferentially using lipid stores. Such switches in substrate use are extensively documented (Jury et al , 2008; Kolditz et al , 2009).…”