mRNA-seq reveals skeletal muscle atrophy in response to handling stress in a marine teleost, the red cusk-eel (Genypterus chilensis)

• Published in: BMC genomics Vol. 16; no. 1; p. 1024
• Main Authors: Aedo, Jorge E, Maldonado, Jonathan, Aballai, Víctor, Estrada, Juan M, Bastias-Molina, Macarena, Meneses, Claudio, Gallardo-Escarate, Cristian, Silva, Herman, Molina, Alfredo, Valdés, Juan A
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 01.12.2015; BioMed Central
• Subjects: Analysis; Animals; Aquaculture industry; Computational Biology - methods; Corticosteroids; Eels; Fishes - genetics; Gene Expression Profiling; Gene Ontology; Genomics; High-Throughput Nucleotide Sequencing; Hydrocortisone - pharmacology; Knowledge; Messenger RNA; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; Muscles; Muscular Atrophy - genetics; Proteolysis; Reproducibility of Results; RNA, Messenger - genetics; Stress, Physiological - genetics; Transcriptome; Ubiquitin
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-015-2232-7

Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress- and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant up-regulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.