Development temperature has persistent effects on muscle growth responses in gilthead sea bream.
ABSTRACT: Initially we characterised growth responses to altered nutritional input at the transcriptional and tissue levels in the fast skeletal muscle of juvenile gilthead sea bream. Fish reared at 21-22°C (range) were fed a commercial diet at 3% body mass d(-1) (non-satiation feeding, NSF) for 4 weeks, fasted for 4d (F) and then fed to satiation (SF) for 21d. 13 out of 34 genes investigated showed consistent patterns of regulation between nutritional states. Fasting was associated with a 20-fold increase in MAFbx, and a 5-fold increase in Six1 and WASp expression, which returned to NSF levels within 16h of SF. Refeeding to satiation was associated with a rapid (<24 h) 12 to 17-fold increase in UNC45, Hsp70 and Hsp90? transcripts coding for molecular chaperones associated with unfolded protein response pathways. The growth factors FGF6 and IGF1 increased 6.0 and 4.5-fold within 16 h and 24 h of refeeding respectively. The average growth in diameter of fast muscle fibres was checked with fasting and significant fibre hypertrophy was only observed after 13d and 21d SF. To investigate developmental plasticity in growth responses we used the same experimental protocol with fish reared at either 17.5-18.5°C (range) (LT) or 21-22°C (range) (HT) to metamorphosis and then transferred to 21-22°C. There were persistent effects of development temperature on muscle growth patterns with 20% more fibres of lower average diameter in LT than HT group of similar body size. Altering the nutritional input to the muscle to stimulate growth revealed cryptic changes in the expression of UNC45 and Hsp90? with higher transcript abundance in the LT than HT groups, whereas there were no differences in the expression of MAFbx and Six1. It was concluded that myogenesis and gene expression patterns during growth are not fixed, but can be modified by temperature during the early stages of the life cycle.
Project description:Here, we analyzed the fast-twitch muscle of juvenile Piaractus mesopotamicus (pacu) submitted to prolonged fasting (30d) and refeeding (6h, 24h, 48h and 30d). We measured the relative rate of weight and length increase (RRIlength and RRIweight), performed shotgun proteomic analysis and did Western blotting for PVALB after 30d of fasting and 30d of refeeding. We assessed the gene expression of igf-1, mafbx and pvalb after 30d of fasting and after 6h, 24h, 48h and 30d of refeeding. We performed a bioinformatic analysis to predict miRNAs that possibly control parvalbumin expression. After fasting, RRIlength, RRIweight and igf-1 expression decreased, while the mafbx expression increased, which suggest that prolonged fasting caused muscle atrophy. After 6h and 24h of refeeding, mafbx was not changed and igf-1 was downregulated, while after 48h of refeeding mafbx was downregulated and igf-1 was not changed. After 30d of refeeding, RRIlength and RRIweight were increased and igf-1 and mafbx expression were not changed. Proteomic analysis identified 99 proteins after 30d of fasting and 71 proteins after 30d of refeeding, of which 23 and 17, respectively, were differentially expressed. Most of these differentially expressed proteins were related to cytoskeleton, muscle contraction, and metabolism. Among these, parvalbumin (PVALB) was selected for further validation. The analysis showed that pvalb mRNA was downregulated after 6h and 24h of refeeding, but was not changed after 30d of fasting or 48h and 30d of refeeding. The Western blotting confirmed that PVALB protein was downregulated after 30d of fasting and 30d of refeeding. The downregulation of the protein and the unchanged expression of the mRNA after 30d of fasting and 30d of refeeding suggest a post-transcriptional regulation of PVALB. Our miRNA analysis predicted 444 unique miRNAs that may target pvalb. In conclusion, muscle atrophy and partial compensatory growth caused by prolonged fasting followed by refeeding affected the muscle proteome and PVALB expression.
Project description:BACKGROUND:Many fish species experience long periods of fasting in nature often associated with seasonal reductions in water temperature and prey availability or spawning migrations. During periods of nutrient restriction, changes in metabolism occur to provide cellular energy via catabolic processes. Muscle is particularly affected by prolonged fasting as myofibrillar proteins act as a major energy source. To investigate the mechanisms of metabolic reorganisation with fasting and refeeding in a saltwater stage of Atlantic salmon (Salmo salar L.) we analysed the expression of genes involved in myogenesis, growth signalling, lipid biosynthesis and myofibrillar protein degradation and synthesis pathways using qPCR. RESULTS:Hierarchical clustering of gene expression data revealed three clusters. The first cluster comprised genes involved in lipid metabolism and triacylglycerol synthesis (ALDOB, DGAT1 and LPL) which had peak expression 3-14d after refeeding. The second cluster comprised ADIPOQ, MLC2, IGF-I and TALDO1, with peak expression 14-32d after refeeding. Cluster III contained genes strongly down regulated as an initial response to feeding and included the ubiquitin ligases MuRF1 and MAFbx, myogenic regulatory factors and some metabolic genes. CONCLUSION:Early responses to refeeding in fasted salmon included the synthesis of triacylglycerols and activation of the adipogenic differentiation program. Inhibition of MuRF1 and MAFbx respectively may result in decreased degradation and concomitant increased production of myofibrillar proteins. Both of these processes preceded any increase in expression of myogenic regulatory factors and IGF-I. These responses could be a necessary strategy for an animal adapted to long periods of food deprivation whereby energy reserves are replenished prior to the resumption of myogenesis.
Project description:This study investigated the effect of fermented diet on growth performance, carcass traits, meat quality and growth of longissimus thoracis (LT) of finishing pigs. A total of 48 finishing pigs [Duroc × (Landrace × Large White), male, 126 ± 5-d-old] weighing 98.76 ± 1.27 kg were randomly assigned to two treatments (eight pens per treatment and three pigs per pen) for a 28-d feeding trial, including control diet and fermented diet. Fermented diet significantly increased the loin eye area and lean mass percentage, decreased backfat thickness and improved meat quality of LT by decreasing the shear force and drip loss at 48 h post slaughter and improving meat sensory characteristics compared with control diet. A fermented diet also significantly increased the abundance of insulin, insulin receptor (IR), myoblast determination protein (MyoD) and myosin heavy chain-I (MyHC-I) transcripts, and the phosphorylation levels of AKT, mTORC1, 4EBP1 and S6K1 in LT, while decreasing the expression of muscle atrophy F-box (MAFbx) and forkhead Box O1 (Foxo1) mRNA transcripts. Moreover, proteomic analysis revealed that differentially expressed proteins predominantly involved in protein synthesis and muscle development were modulated by fermented diet. Our results indicated that a fermented diet improved meat quality and enhanced LT growth of finishing pigs by increasing insulin/AKT/mTORC1 protein synthesis cascade and activating the Foxo1/MAFbx pathway, along with the regulation of ribosomal protein and proteins involved in muscle contraction and muscle hypertrophy.
Project description:Recepteur d'origine nantais (RON) has been implicated in cell proliferation, metastasis, and chemoresistance of various human malignancies. The short-form RON (sf-RON) encoded by RON transcripts was overexpressed in gastric cancer tissues, but its regulatory functions remain illustrated. Here, we found that sf-RON promoted gastric cancer cell proliferation by enhancing glucose metabolism. Furthermore, sf-RON was proved to induce the ?-catenin expression level through the AKT1/GSK3? signaling pathway. Meanwhile, the binding sites of ?-catenin were identified in the promoter region of SIX1 and it was also demonstrated that ?-catenin positively regulated SIX1 expression. SIX1 enhanced the promoter activity of key proteins in glucose metabolism, such as GLUT1 and LDHA. Results indicated that sf-RON regulated the cell proliferation and glucose metabolism of gastric cancer by participating in a sf-RON/?-catenin/SIX1 signaling axis and had significant implications for choosing the therapeutic target of gastric cancer.
Project description:In a study of household contacts (HHC), households were categorized into High (HT) and Low (LT) transmission groups based on the proportion of HHC with a positive tuberculin skin test. The Mycobacterium tuberculosis (Mtb) strains from HT and LT index cases of the households were designated Mtb-HT and Mtb-LT, respectively. We found that C3HeB/FeJ mice infected with Mtb-LT strains exhibited significantly higher bacterial burden compared to Mtb-HT strains and also developed diffused inflammatory lung pathology. In stark contrast, a significant number of mice infected with Mtb-HT strains developed caseating granulomas, a lesion type with high potential to cavitate. None of the Mtb-HT infected animals developed diffused inflammatory lung pathology. A link was observed between increased in vitro replication of Mtb-LT strains and their ability to induce significantly high lipid droplet formation in macrophages. These results support that distinct early interactions of Mtb-HT and Mtb-LT strains with macrophages and subsequent differential trajectories in pathological disease may be the mechanism underlying their transmission potential.
Project description:Skeletal muscle is capable of phenotypic adaptation to environmental factors, such as nutrient availability, by altering the balance between muscle catabolism and anabolism that in turn coordinates muscle growth. Small noncoding RNAs, known as microRNAs (miRNAs), repress the expression of target mRNAs, and many studies have demonstrated that miRNAs regulate the mRNAs of catabolic and anabolic genes. We evaluated muscle morphology, gene expression of components involved in catabolism, anabolism and energetic metabolism and miRNAs expression in both the fast and slow muscle of juvenile pacu (Piaractus mesopotamicus) during food restriction and refeeding. Our analysis revealed that short periods of food restriction followed by refeeding predominantly affected fast muscle, with changes in muscle fiber diameter and miRNAs expression. There was an increase in the mRNA levels of catabolic pathways components (FBXO25, ATG12, BCL2) and energetic metabolism-related genes (PGC1? and SDHA), together with a decrease in PPAR?/? mRNA levels. Interestingly, an increase in mRNA levels of anabolic genes (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) was also observed during food restriction. After refeeding, muscle morphology showed similar patterns of the control group; the majority of genes were slightly up- or down-regulated in fast and slow muscle, respectively; the levels of all miRNAs increased in fast muscle and some of them decreased in slow muscle. Our findings demonstrated that a short period of food restriction in juvenile pacu had a considerable impact on fast muscle, increasing the expression of anabolic (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) and energetic metabolism genes. The miRNAs (miR-1, miR-206, miR-199 and miR-23a) were more expressed during refeeding and while their target genes (IGF-1, mTOR, PGC1? and MAFbx), presented a decreased expression. The alterations in mTORC1 complex observed during fasting may have influenced the rates of protein synthesis by using amino acids from protein degradation as an alternative mechanism to preserve muscle phenotype and metabolic demand maintenance.
Project description:In the present study, we conducted an RNA-Seq analysis to characterize the genes and pathways involved in acute thermal and cold stress responses in the liver of black rockfish, a viviparous teleost that has the ability to cope with a wide range of temperature changes. A total of 584 annotated differentially expressed genes (DEGs) were identified in all three comparisons (HT vs NT, HT vs LT and LT vs NT). Based on an enrichment analysis, DEGs with a potential role in stress accommodation were classified into several categories, including protein folding, metabolism, immune response, signal transduction, molecule transport, membrane, and cell proliferation/apoptosis. Considering that thermal stress has a greater effect than cold stress in black rockfish, 24 shared DEGs in the intersection of the HT vs LT and HT vs NT groups were enriched in 2 oxidation-related gene ontology (GO) terms. Nine important heat-stress-reducing pathways were significantly identified and classified into 3 classes: immune and infectious diseases, organismal immune system and endocrine system. Eight DEGs (early growth response protein 1, bile salt export pump, abcb11, hsp70a, rtp3, 1,25-dihydroxyvitamin d(3) 24-hydroxylase, apoa4, transcription factor jun-b-like and an uncharacterized gene) were observed among all three comparisons, strongly implying their potentially important roles in temperature stress responses.
Project description:It remains unknown why upon similar acute/subacute painful conditions, pain persists in some individuals while in others it resolves. Genetic factors, mood, and functional alterations, particularly involving the mesolimbic network, appear to be key. In order to explore potential susceptibility/resistance factors, we screened a large population of rats with a peripheral neuropathy, and we isolated a small subset (<15%) that presented high thresholds (HT) to mechanical allodynia (reduced pain manifestation). The phenotype was sustained over 12 weeks and was associated with higher hedonic behavior when compared with low threshold subjects (LT). The nucleus accumbens (NAc) of HT and LT animals were isolated for proteomic analysis by Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS). Two hundred and sevety-nine proteins proteins displayed different expression between LT and HT animals/subjects.
Project description:Senescence leads to declines in fruit quality and shortening of shelf life. It is known that low temperatures (LTs) efficiently delay fruit senescence and that high temperatures (HTs) accelerate senescence. However, the molecular mechanism by which temperature affects senescence is unclear. Herein, through multiomics analyses of fruits subjected to postharvest HT, LT, and room temperature treatments, a total of 56 metabolic compounds and 700 mRNAs were identified to be associated with fruit senescence under HT or LT conditions. These compounds could be divided into antisenescent (I?III) and prosenescent (IV?VI) types. HT affected the expression of 202 mRNAs to enhance the biosynthesis of prosenescent compounds of types V and VI and to inhibit the accumulation of antisenescent compounds of types II and III. LT affected the expression of 530 mRNAs to promote the accumulation of antisenescent compounds of types I and II and to impede the biosynthesis of prosenescent compounds of types IV and V. Moreover, 16 microRNAs were isolated in response to HT or LT conditions and interacted with the mRNAs associated with fruit senescence under HT or LT conditions. Transient transformation of pear fruit showed that one of these microRNAs, Novel_188, can mediate fruit senescence by interacting with its target Pbr027651.1. Thus, both HT and LT conditions can affect fruit senescence by affecting microRNA-mRNA interactions, but the molecular networks are different in pear fruit.
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.