Project description:Amino acids (AA) and IGF1 have demonstrated to play essential roles in protein synthesis and fish muscle growth. The myoblast cell culture is useful to study the muscle regulation, and omics data have contributed enormously to understand its molecular biology. However, to our knowledge, no study has performed large-scale sequencing of fish cultured muscle cells stimulated with pro-growth signals. In this work, we obtained the transcriptome and microRNAome of pacu (Piaractus mesopotamicus) cultured myotubes treated with AA or IGF1. We identified 1228 and 534 genes differentially expressed by AA and IGF1. Enrichment analysis showed that AA treatment induced chromosomal changes, mitosis, and muscle differentiation, while IGF1 modulated IGF/PI3K signalling, metabolic alteration, and matrix structure. In addition, potential molecular markers were similarly modulated by both treatments. Muscle-miRNAs (miR-1, -133, -206 and -499) were up-regulated especially in AA samples, and we identified molecular networks with omics integration. Two pairs of genes and miRNAs showed high level of relationship, and involvement in myogenesis and muscle growth: marcksb and miR-29b in AA, and mmp14b and miR-338-5p in IGF1. Our work helps to elucidate fish muscle physiology and metabolism, highlights potential molecular markers, and creates perspective for improvements in aquaculture and in vitro meat production.
Project description:Amino acids (AA) and IGF1 have demonstrated to play essential roles in protein synthesis and fish muscle growth. The myoblast cell culture is useful to study the muscle regulation, and omics data have contributed enormously to understand its molecular biology. However, to our knowledge, no study has performed large-scale sequencing of fish cultured muscle cells stimulated with pro-growth signals. In this work, we obtained the transcriptome and microRNAome of pacu (Piaractus mesopotamicus) cultured myotubes treated with AA or IGF1. We identified 1228 and 534 genes differentially expressed by AA and IGF1. Enrichment analysis showed that AA treatment induced chromosomal changes, mitosis, and muscle differentiation, while IGF1 modulated IGF/PI3K signalling, metabolic alteration, and matrix structure. In addition, potential molecular markers were similarly modulated by both treatments. Muscle-miRNAs (miR-1, -133, -206 and -499) were up-regulated especially in AA samples, and we identified molecular networks with omics integration. Two pairs of genes and miRNAs showed high level of relationship, and involvement in myogenesis and muscle growth: marcksb and miR-29b in AA, and mmp14b and miR-338-5p in IGF1. Our work helps to elucidate fish muscle physiology and metabolism, highlights potential molecular markers, and creates perspective for improvements in aquaculture and in vitro meat production.
Project description: In fish, the slow-twitch skeletal muscle fibres have an oxidative metabolism, present peripherical location in the red muscle, and are used for sustained movements. They may respond to alterations in food availability differently than the fast-twitch muscle. The aim of this manuscript was to study the slow-twitch muscle fibres of Piaractus Mesopotamicus, a neotropical fish, submitted to 30 days of fasting (D30) followed by one day (D31) or 30 days of refeeding (D60). The treated animals were compared with regularly fed fish. To verify the presence of atrophy and hypertrophy, we performed histological analysis of muscle fibre diameter in D30 and D60, and RT-qPCR gene expression analysis of catabolic (murfa, murfb, mafbx) and anabolic genes (igf-1, mTOR) in D30, D31 and D60. The gene expression of the allergen and Ca2+-carrier parvalbumin (pvalb) was also measured in D30, D31 and D60. The proteome of slow-twitch fibres at D30 and D60 was obtained by shotgun proteomics (digestion of proteins with trypsin followed by LC-MS/MS identification), and the proteins differentially expressed were used to construct protein interaction networks. The histological analysis showed no difference between treated fish in relation to the control. The expression of catabolic and anabolic genes was not changed, except for the negative regulation of igf-1 in D30 and of mtor in D31. The expression of pvalb was not changed in D30 and D60, but it was decreased in D31. The proteomic analysis identified 169 proteins in D30 (24 upregulated and 18 downregulated) and 170 proteins in D60 (17 upregulated and 21 downregulated). Many of them were related to energetic metabolism, including lipid metabolism, as shown by the protein network analysis. These results enlarge our understanding of the acclimation of slow-twitch fibres to changes in nutrient availability and set a path for future research.
Project description:Skeletal muscle in fish presents a high plasticity controlled by a dynamic balance between anabolic and catabolic signaling pathways. Decreased food availability can inhibit muscle growth and trigger muscle catabolism pathways, thu promoting muscle atrophy. In contrast, anabolism may be favored during restoration of food supply, promoting the muscle growth. Considering this, we analyzed fast-twitch muscle of juvenile Piaractus mesopotamicus (pacu) submitted to a prolonged fasting (30 days) and refeeding (up to 30 days) using shotgun proteomics and gene expression analysis. The relative rate of weight and length increase, as well as the expression of mafbx and igf -1 genes, suggest that prolonged fasting caused muscle atrophy and that 30 days of refeeding led to partial compensatory growth. Shotgun proteomics analysis identified 99 proteins after fasting and 71 proteins after refeeding periods, of which 23 and 17 were differentially expressed after fasting and after 30 days of refeeding, respectively. Most of these differentially expressed proteins were related to cytoskeleton, muscle contraction and muscle metabolism. Among these, parvalbumin (PVALB), a calcium-binding protein and food allergen, was selected for further RT-qPCR analysis, which showed that pvalb mRNA was not changed after 30 days of fasting and 30 days of refeeding, but it was downregulated after 6h and 24h of refeeding. This suggests a post-transcriptional regulation of PVALB in fish muscle. In conclusion, our results suggest that muscle atrophy and partial compensatory growth caused by prolonged fasting and refeeding affected the muscle proteome and PVALB expression. Our results can contribute to the understanding of muscle anabolic and catabolic pathways in response to changes in food availability.