RTH-149 Cell Line, a Useful Tool to Decipher Molecular Mechanisms Related to Fish Nutrition.

Guillaume Morin,Karine Dias,Florian Beaumatin,Karine Pinel,Iban Seiliez

doi:10.3390/cells9081754

Abstract

Nowadays, aquaculture provides more than 50% of fish consumed worldwide but faces new issues that challenge its sustainability. One of them relies on the replacement of fish meal (FM) in aquaculture feeds by other protein sources without deeply affecting the whole organism’s homeostasis. Multiple strategies have already been tested using in vivo approaches, but they hardly managed to cope with the multifactorial problems related to the complexities of fish biology together with new feed formulations. In this context, rainbow trout (RT) is particularly concerned by these problems, since, as a carnivorous fish, dietary proteins provide the amino acids required to supply most of its energetic metabolism. Surprisingly, we noticed that in vitro approaches considering RT cell lines as models to study RT amino acid metabolism were never previously used. Therefore, we decided to investigate if, and how, three major pathways described, in other species, to be regulated by amino acid and to control cellular homeostasis were functional in a RT cell line called RTH-149—namely, the mechanistic Target Of Rapamycin (mTOR), autophagy and the general control nonderepressible 2 (GCN2) pathways. Our results not only demonstrated that these three pathways were functional in RTH-149 cells, but they also highlighted some RT specificities with respect to the time response, amino acid dependencies and the activation levels of their downstream targets. Altogether, this article demonstrated, for the first time, that RT cell lines could represent an interesting alternative of in vivo experimentations for the study of fish nutrition-related questions.

Highlights

By 2050, the global population is expected to reach an unprecedented and alarming density.Among concerns raised by this increase, solutions need to be found to feed more than nine billion humans with affordable and nutritious foods produced with respect to the environment [1]
We sought to evaluate if RTH-149 cells are prone to activate this pathway upon amino acid and serum deprivation, hereafter referred to as starvation, by assessing the time course of the gene expression described to be transcriptionally regulated by the integrated stress response (ISR) (Figure 1A)
We sought to investigate the usefulness of a rainbow trout (RT) cell line to address nutrition-related questions by focusing our work on three major pathways shown to regulate cell homeostasis through their regulation by amino acids

Summary

Introduction

By 2050, the global population is expected to reach an unprecedented and alarming density. Among concerns raised by this increase, solutions need to be found to feed more than nine billion humans with affordable and nutritious foods produced with respect to the environment [1]. In this context, many expectations are placed in the aquaculture field. Aquaculture provides already more than half of the fish for human consumption every year, contributing to feeding a global population with a food widely recognized for its benefits in health. One of the most important objectives of this field is to replace FM and FO from fish feed by other protein and lipid sources

Methods

Results

Conclusion