Revealing the transcriptional profile of fish muscle cells in vitro and in vivo: Insights to improve fish muscle culture

In vitro experiments have contributed to numerous fields of knowledge, including fish skeletal muscle. Despite improved strategies, in vitro assays still show discrepancies with in vivo systems, especially for non-model organisms. In this sense, we characterized the transcriptional profile of pacu ( Piaractus mesopotamicus ) muscle cells in vitro and in vivo . Processes related to proliferation, glycolytic metabolism, and extracellular matrix were enriched in vitro , while energy production, muscle contraction, and amino acid processing were enriched in vivo . Through qPCR, the genes fn1a (fibronectin 1a) , hk1 (hexokinase 1), and ctnnb1 (catenin beta 1) , respectively related to extracellular matrix, glycolytic metabolism, and cell proliferation and differentiation, were highly expressed in vitro . The genes ckma (creatine kinase, muscle a) , acat1 (acetyl-CoA acetyltransferase 1) , mdh2 (malate dehydrogenase 2), and pkmb (pyruvate kinase M1/2b) , respectively associated with ATP production, fatty acid oxidation, oxidative and glycolytic metabolism, and the genes musk (muscle, skeletal, receptor tyrosine kinase) , chrna1 (cholinergic receptor, nicotinic, alpha 1) and clu (clusterin) , involved in cell signaling, were highly expressed in vivo . Overall, our results indicate that the main limitation of in vitro muscle cell model is the maintenance of an embryonic-like molecular state, whereas in vivo muscle displays a mature transcriptional profile, providing a molecular basis to guide future strategies for improving fish muscle cell culture systems and supporting advances in sustainable aquaculture and in vitro meat production. • Fish in vitro muscle cells limit energy generation pathways when isolated • Cell communication is a key point for fish in vitro muscle cell proliferation • Extracellular matrix is essential for the in vitro maintenance of fish muscle cells • Findings highlight the needs, limitations, and biology of fish muscle cell culture • Results can be applied in the future development of cultured fish meat.