EGF receptor (EGFR) inhibition promotes a slow-twitch oxidative, over a fast-twitch, muscle phenotype.
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ABSTRACT:
SUBMITTER: Ciano M
PROVIDER: S-EPMC6592914 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A new application of the reduced representation bisulfite sequencing method was developed using low-DNA input to investigate the epigenetic profile of human slow- and fast-twitch skeletal muscle fibers. Successful library construction was completed with as little as 15 ng of DNA, and high-quality sequencing data were obtained with 32 ng of DNA. Analysis identified 143,160 differentially methylated CpG sites across 14,046 genes. In both fiber types, selected genes predominantly expressed in slow or fast fibers were hypomethylated, which was supported by the RNA-sequencing analysis. These are the first fiber type-specific methylation data from human skeletal muscle and provide a unique platform for future research.NEW & NOTEWORTHY This study validates a low-DNA input reduced representation bisulfite sequencing method for human muscle biopsy samples to investigate the methylation patterns at a fiber type-specific level. These are the first fiber type-specific methylation data reported from human skeletal muscle and thus provide initial insight into basal state differences in myosin heavy chain I and IIa muscle fibers among young, healthy men.
| S-EPMC5407195 | biostudies-literature
Project description:The contractile properties of fast-twitch and slow-twitch skeletal muscles are primarily determined by the myosin isoform content and modulated by a variety of sarcomere proteins. X-ray diffraction studies of regulatory mechanisms in muscle contraction have focused predominately on fast- or mixed-fibre muscle with slow muscle being much less studied. Here, we used time-resolved X-ray diffraction to investigate the dynamic behaviour of the myofilament proteins in relatively pure slow-twitch-fibre rat soleus (SOL) and pure fast-twitch-fibre rat extensor digitorum longus (EDL) muscle during twitch and tetanic contractions at optimal length. During twitch contractions the diffraction signatures indicating a transition in the myosin heads from ordered OFF states, where heads are held close to the thick filament backbone, to disordered ON states, where heads are free to bind to thin filaments, were found in EDL and not in SOL muscle. During tetanic contraction, changes in the disposition of myosin heads as active tension develops is a quasi-stepwise process in EDL muscle whereas in SOL muscle this relationship appears to be linear. The observed reduced extensibility of the thick filaments in SOL muscle as compared to EDL muscles indicates a molecular basis for this behaviour. These data indicate that for the EDL, thick filament activation is a cooperative strain-induced mechano-sensing mechanism, whereas for the SOL, thick filament activation has a more graded response. These different approaches to thick filament regulation in fast- and slow-twitch muscles may be adaptations for short-duration, strong contractions versus sustained, finely controlled contractions, respectively. KEY POINTS: Fast-twitch muscle and slow-twitch muscle are optimized for strong, short-duration contractions and for tonic postural activity, respectively. Structural events (OFF to ON transitions) in the myosin-containing thick filaments in fast muscle help determine the timing and strength of contractions, but these have not been studied in slow-twitch muscle. The X-ray diffraction signatures of structural OFF to ON transitions are different in fast extensor digitorum longus (EDL) and slow soleus (SOL) muscle, being completely absent during twitches in soleus muscle and blunted during tetanic contractions SOL as compared to EDL Quasi-stepwise thick filament structural OFF to ON transitions in fast twitch muscle may be an adaptation for rapid, ballistic movements, whereas more graded OFF to ON structural transitions in slow-twitch muscle may be an adaptation for slower, finer motions.
| S-EPMC9772099 | biostudies-literature
Project description:Muscle myosin heads, in the absence of actin, have been shown to exist in two states, the relaxed (turnover ∼0.05 s-1) and super-relaxed states (SRX, 0.005 s-1) using a simple fluorescent ATP chase assay (Hooijman, P. et al (2011) Biophys. J.100, 1969-1976). Studies have normally used purified proteins, myosin filaments, or muscle fibers. Here we use muscle myofibrils, which retain most of the ancillary proteins and 3-D architecture of muscle and can be used with rapid mixing methods. Recording timescales from 0.1 to 1000 s provides a precise measure of the two populations of myosin heads present in relaxed myofibrils. We demonstrate that the population of SRX states is formed from rigor cross bridges within 0.2 s of relaxing with fluorescently labeled ATP, and the population of SRX states is relatively constant over the temperature range of 5 °C-30 °C. The SRX population is enhanced in the presence of mavacamten and reduced in the presence of deoxy-ATP. Compared with myofibrils from fast-twitch muscle, slow-twitch muscle, and cardiac muscles, myofibrils require a tenfold lower concentration of mavacamten to be effective, and mavacamten induced a larger increase in the population of the SRX state. Mavacamten is less effective, however, at stabilizing the SRX state at physiological temperatures than at 5 °C. These assays require small quantities of myofibrils, making them suitable for studies of model organism muscles, human biopsies, or human-derived iPSCs.
| S-EPMC8867123 | biostudies-literature
Project description:The skeletal muscle fiber profile is closely related to livestock meat quality. However, the molecular mechanisms determining muscle fiber types in donkeys are not completely understood. In this study, we selected the psoas major muscle (PM; mainly composed of oxidative-type muscle fibers) and biceps femoris muscle (BF; mainly composed of glycolytic-type muscle fibers) and systematically compared their mRNA and microRNA transcriptomes via RNA-seq. We identified a total of 2881 differentially expressed genes (DEGs) and 21 known differentially expressed miRNAs (DEmiRs). Furthermore, functional enrichment analysis showed that the DEGs were mainly involved in energy metabolism and actin cytoskeleton regulation. The glycolysis/gluconeogenesis pathway (including up-regulated genes such as PKM, LDHA, PGK1 and ALDOA) was more highly enriched in BF, whereas the oxidative phosphorylation pathway and cardiac muscle contraction (including down-regulated genes such as LDHB, ATP2A2, myosin-7 (MYH7), TNNC1, TPM3 and TNNI1) was more enriched in PM. Additionally, we identified several candidate miRNA-mRNA pairs that might regulate muscle fiber types using the integrated miRNA-mRNA analysis. Combined with the results of protein-protein interaction (PPI) analysis, some interesting DEGs (including ACTN3, TNNT3, TPM2, TNNC2, PKM, TNNC1 and TNNI1) might be potential candidate target genes involved in the miRNA-mediated regulation of the myofibril composition. This study is the first to indicate that DEmiRs, especially eca-miR-193a-5p and eca-miR-370, and potential candidate target genes that are mainly involved in actin binding (e.g., ACTN3, TNNT3 and TNNC1) and the glycolysis/gluconeogenesis pathways (e.g., PKM) might coregulate the myofibril composition in donkeys. This study may provide useful information for improving meat quality traits in Dezhou donkeys.
| S-EPMC9498731 | biostudies-literature
Project description:Pacu (Piaractus mesopotamicus) is a Brazilian fish with a high economic value in pisciculture due to its rusticity and fast growth. Postnatal growth of skeletal muscle in fish occurs by hyperplasia and/or hypertrophy, processes that are dependent on the proliferation and differentiation of myoblasts. A class of small noncoding RNAs, known as microRNAs (miRNAs), represses the expression of target mRNAs, and many studies have demonstrated that miR-1, miR-133, miR-206 and miR-499 regulate different processes in skeletal muscle through the mRNA silencing of hdac4 (histone deacetylase 4), srf (serum response factor), pax7 (paired box 7) and sox6 ((sex determining region Y)-box 6), respectively. The aim of our work was to evaluate the expression of these miRNAs and their putative target mRNAs in fast- and slow-twitch skeletal muscle of pacu during growth. We used pacus in three different development stages: larval (aged 30 days), juvenile (aged 90 days and 150 days) and adult (aged 2 years). To complement our study, we also performed a pacu myoblast cell culture, which allowed us to investigate miRNA expression in the progression from myoblast proliferation to differentiation. Our results revealed an inverse correlation between the expression of the miRNAs and their target mRNAs, and there was evidence that miR-1 and miR-206 may regulate the differentiation of myoblasts, whereas miR-133 may regulate the proliferation of these cells. miR-499 was highly expressed in slow-twitch muscle, which suggests its involvement in the specification of the slow phenotype in muscle fibers. The expression of these miRNAs exhibited variations between different development stages and between distinct muscle twitch phenotypes. This work provides the first identification of miRNA expression profiles in pacu skeletal muscle and suggests an important role of these molecules in muscle growth and in the maintenance of the muscle phenotype.
| S-EPMC4631509 | biostudies-literature
Project description:Muscle development requires myoblast differentiation and muscle fiber formation. Myod family inhibitor (Mdfi) inhibits myogenic regulatory factors in NIH3T3 cells, but how Mdfi regulates myoblast myogenic development is still unclear. In the present study, we constructed an Mdfi-overexpression (Mdfi-OE) C2C12 cell line by the CRISPR/Cas9 system and performed RNA-seq on Mdfi-OE and wild-type (WT) C2C12 cells. The RNA-seq results showed that the calcium signaling pathway was the most significant. We also established the regulatory networks of Mdfi-OE on C2C12 cell differentiation and muscle fiber type transformation and identified hub genes. Further, both RNA-seq and experimental verification demonstrated that Mdfi promoted C2C12 cell differentiation by upregulating the expression of Myod, Myog, and Myosin. We also found that the positive regulation of Mdfi on fast-to-slow-twitch muscle fiber transformation is mediated by Myod, Camk2b, and its downstream genes, such as Pgc1a, Pdk4, Cs, Cox4, Acadm, Acox1, Cycs, and Atp5a1. In conclusion, our results demonstrated that Mdfi promotes C2C12 cell differentiation and positively modulates fast-to-slow-twitch muscle fiber transformation. These findings further our understanding of the regulatory mechanisms of Mdfi in myogenic development and muscle fiber type transformation. Our results suggest potential therapeutic targets for muscle- and metabolic-related diseases.
| S-EPMC7862576 | biostudies-literature
Project description:Skeletal muscle fiber types can contribute in part to affecting pork quality parameters. Biceps femoris (Bf) (fast muscle or white muscle) and Soleus (Sol) (slow muscle or red muscle) are two typical skeletal muscles characterized by obvious muscle fiber type differences in pigs. However, the critical proteins and potential regulatory mechanisms regulating porcine skeletal muscle fibers have yet to be clearly defined. In this study, the isobaric Tag for Relative and Absolute Quantification (iTRAQ)-based proteome was used to identify the key proteins affecting the skeletal muscle fiber types with Bf and Sol, by integrating the previous transcriptome data, while function enrichment analysis and a protein-protein interaction (PPI) network were utilized to explore the potential regulatory mechanisms of skeletal muscle fibers. A total of 126 differentially abundant proteins (DAPs) between the Bf and Sol were identified, and 12 genes were found to be overlapping between differentially expressed genes (DEGs) and DAPs, which are the critical proteins regulating the formation of skeletal muscle fibers. Functional enrichment and PPI analysis showed that the DAPs were mainly involved in the skeletal-muscle-associated structural proteins, mitochondria and energy metabolism, tricarboxylic acid cycle, fatty acid metabolism, and kinase activity, suggesting that PPI networks including DAPs are the main regulatory network affecting muscle fiber formation. Overall, these data provide valuable information for understanding the molecular mechanism underlying the formation and conversion of muscle fiber types, and provide potential markers for the evaluation of meat quality.
| S-EPMC9497725 | biostudies-literature
Project description:Localization microscopy is a fairly recently introduced super-resolution fluorescence imaging modality capable of achieving nanometre-scale resolution. We have applied the dSTORM variation of this method to image intracellular molecular assemblies in skeletal muscle fibres which are large cells that critically rely on nanoscale signalling domains, the triads. Immunofluorescence staining in fixed adult rat skeletal muscle sections revealed clear differences between fast- and slow-twitch fibres in the molecular organization of ryanodine receptors (RyRs; the primary calcium release channels) within triads. With the improved resolution offered by dSTORM, abutting arrays of RyRs in transverse view of fast fibres were observed in contrast to the fragmented distribution on slow-twitch muscle that were approximately 1.8 times shorter and consisted of approximately 1.6 times fewer receptors. To the best of our knowledge, for the first time, we have quantified the nanometre-scale spatial association between triadic proteins using multi-colour super-resolution, an analysis difficult to conduct with electron microscopy. Our findings confirm that junctophilin-1 (JPH1), which tethers the sarcoplasmic reticulum ((SR) intracellular calcium store) to the tubular (t-) system at triads, was present throughout the RyR array, whereas JPH2 was contained within much smaller nanodomains. Similar imaging of the primary SR calcium buffer, calsequestrin (CSQ), detected less overlap of the triad with CSQ in slow-twitch muscle supporting greater spatial heterogeneity in the luminal Ca2+ buffering when compared with fast twitch muscle. Taken together, these nanoscale differences can explain the fundamentally different physiologies of fast- and slow-twitch muscle.
| S-EPMC4233733 | biostudies-literature
Project description:The right legs of 3 months old CD1 mice were denervated by unilaterally cutting the sciatic nerve at the level of trochanter, resulting in a permanent denervation of the lower hindleg. At the indicated times, animals were killed by cervical dislocation and tibialis anterior (TA) muscles were dissected out and frozen in liquid nitrogen. The expression analysis was carried out at five time points, namely just after denervation (time 0) and 1, 3, 7 and 14 days after nerve interruption. The contralateral, left TA muscle from the same individual served as innervated control. We reversed labeling of denervated and contralateral samples in each experiment, thus carrying out two separate hybridizations for each time point. Keywords = mouse Keywords = fast-twitch muscle Keywords = denervation Keywords = atrophy Keywords: time-course
2005-09-21 | GSE1893 | GEO
Project description:1. A method is described for the electrophoretic analysis of intact myosin in polyacrylamide gel in a buffer system containing 0.02 M-pyrophosphate and 10% (v/v) glycerol, pH 8.8. 2. In this system chicken skeletal-muscle myosins reveal five distinct electrophoretic components, three components from the fast-twitch posterior latissimus dorsi muscle and two slower-migrating components from the slow-twitch anterior latissimus dorsi muscle. 3. The Ca2+-activated ATPase (adenosine triphosphatase) activity of myosin components was measured by densitometric scanning of the gel for the Ca3(PO4)2 precipitate formed during the ATPase reaction and subsequently for stained protein. Each component from the same muscle appears to have identical ATPase activity, but components from the fast-twitch muscle had an activity 2.2 times higher than those from the slow-twitch muscle. 4. On re-electrophoresis in the same buffer system, individual fractions of fast-twitch myosin did not reproduce the three-band pattern of the original myosin, but migrated at rates consistent with their original mobility. 5. Analysis of the mobility of the three fast-twitch myosin components in gels of different concentrations suggests that they are not stable oligomers of each other. 6. It is suggested that these components of fast-twitch myosin and slow-twitch myosin are isoenzymes of myosin.
| S-EPMC1163819 | biostudies-other