ABSTRACT: The miRNA Transcriptome directly Reflect the Physiological and Biochemical Differences between Red, White and Intermediate Muscle Fiber Types
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that can regulate the expression of their target genes at post-transcriptional level. Skeletal muscle comprises different �ber types that can be broadly classified as red, intermediate and white fiber types. Recently, a set of miRNAs were identified to be expressed on a fiber type-specific manner between red and white fiber types. Nonetheless, an integral explanation of the miRNA transcriptome differences in all three fiber types is long overdue. Herein, we collected 15 kinds of porcine skeletal muscles from different anatomic locations, which were then clearly divided into red, white and intermediate fiber type based on the hierarchical clustering analysis for the ratios of myosin heavy chain (MHC) isoforms. We further illustrated that three muscles, which typically represented each muscle fiber type (i.e. red: peroneal longus (PL), intermediate: psoas major muscle (PMM), white: longissimus dorsi muscle (LDM)), have distinct metabolic patterns of mitochondrial and glycolytic enzyme levels. In addition, we constructed the small RNA libraries for PL, PMM and LDM using deep sequencing approach. Results showed that, the differentially expressed miRNAs were mainly enriched in PL and played a vital role in myogenesis and energy metabolism. Overall, this comprehensive analysis will contribute to a better understanding of the miRNA regulatory mechanism for the phenotypic diversity of skeletal muscles. 3 sample
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that can regulate the expression of their target genes at post-transcriptional level. Skeletal muscle comprises different fiber types that can be broadly classified as red, intermediate and white fiber types. Recently, a set of miRNAs were identified to be expressed on a fiber type-specific manner between red and white fiber types. Nonetheless, an integral explanation of the miRNA transcriptome differences in all three fiber types is long overdue. Herein, we collected 15 kinds of porcine skeletal muscles from different anatomic locations, which were then clearly divided into red, white and intermediate fiber type based on the hierarchical clustering analysis for the ratios of myosin heavy chain (MHC) isoforms. We further illustrated that three muscles, which typically represented each muscle fiber type (i.e. red: peroneal longus (PL), intermediate: psoas major muscle (PMM), white: longissimus dorsi muscle (LDM)), have distinct metabolic patterns of mitochondrial and glycolytic enzyme levels. In addition, we constructed the small RNA libraries for PL, PMM and LDM using deep sequencing approach. Results showed that, the differentially expressed miRNAs were mainly enriched in PL and played a vital role in myogenesis and energy metabolism. Overall, this comprehensive analysis will contribute to a better understanding of the miRNA regulatory mechanism for the phenotypic diversity of skeletal muscles.
Project description:Background: skeletal muscle is a complex, versatile tissue composed of a variety of functionally diverse fiber types. Although the biochemical, structural and functional properties of myofibers have been the subject of intense investigation for the last decades, understanding molecular processes regulating fiber type diversity is still complicated by the heterogeneity of cell types present in the whole muscle organ. Methodology/Principal Findings: we have produced a first catalogue of genes expressed in mouse slow-oxidative (type 1) and fast-glycolytic (type 2B) fibers through transcriptome analysis at the single fiber level (microgenomics). Individual fibers were obtained from murine soleus and EDL muscles and initially classified by myosin heavy chain isoform content. Gene expression profiling on high density DNA oligonucleotide microarrays showed that both qualitative and quantitative improvements were achieved, compared to results with standard muscle homogenate. First, myofiber profiles were virtually free from non-muscle transcriptional activity. Second, thousands of muscle-specific genes were identified, leading to a better definition of gene signatures in the two fiber types as well as the detection of metabolic and signaling pathways that are differentially activated in specific fiber types. Several regulatory proteins showed preferential expression in slow myofibers. Discriminant analysis revealed novel genes that could be useful for fiber type functional classification. Conclusions/Significance: as gene expression analyses at the single fiber level significantly increased the resolution power, this innovative approach would allow a better understanding of the adaptive transcriptomic transitions occurring in myofibers under physiological and pathological conditions.
Project description:White adipose tissue is a major site of energy storage and plays a noteworthy role in physiological homeostasis and metabolic disease. Different types of fat have been demonstrated to exhibit distinct metabolic and inflammatory profiles and are differentially associated with disease risk. It is unclear whether these differences are intrinsic to the pre-differentiated stage. We address this challenging question using RNA sequencing on clonally-expanded human white preadipocyte cell lines. We have identified differences in gene expression that are separate from the process of browning and beiging.
Project description:Upland cotton (Gossypium hirsutum L.) is one of the world’s most important fiber crops, accounting for more than 90% of all cotton production. While their wild progenitors have relatively short and coarse, often tan-colored fibers, modern cotton cultivars possess longer, finer, stronger, and whiter fiber. In this study, the wild and cultivated cottons (YU-3 and TM-1) selected show significant differences on fibers at 10 day post-anthesis (DPA), 20 DPA and mature stages at the physiological level. In order to explore the effects of domestication, reveal molecular mechanisms underlying these phenotypic differences and better inform our efforts to further enhance cotton fiber quality, an iTRAQ-facilitated proteomic methods were performed on developing fibers. There were 6990 proteins identified, among them 336 were defined as differentially expressed proteins (DEPs) between fibers of wild versus domesticated cotton. The down- or up-regulated proteins in wild cotton were involved in Phenylpropanoid biosynthesis, Zeatin biosynthesis, Fatty acid elongation and other processes. Association analysis between transcroptome and proteome showed positive correlations between transcripts and proteins at both 10 DPA and 20 DPA. The difference of proteomics had been verified at the mRNA level by qPCR, also at physiological and biochemical level by POD activity determination and ZA content estimation. This work corroborate the major pathways involved in cotton fiber development and demonstrate that POD activity and zeatin content have a great potential related to fiber elongation and thickening.
Project description:Skeletal muscles are composed of a heterogeneous collection of fiber types with different physiological adaption in response to a stimulus and disease-related conditions. Each fiber has a specific molecular expression of myosin heavy chain molecules (MyHC). So far MyHCs are currently the best marker proteins for characterization of individual fiber types and several proteome profiling studies have helped to dissect the molecular signature of whole muscles and individual fibers. Herein, we describe a mass spectrometric workflow to measure skeletal muscle fiber type-specific proteomes. To bypass the limited quantities of protein in single fibers, we developed a Proteomics high-throughput Fiber Typing (ProFiT) approach enabling profiling of MyHC in single fibers. Aliquots of protein extracts from separated muscle fibers were subjected to capillary LC-MS gradients to profile MyHC isoforms in a 96-well format. Muscle fibers with the same MyHC protein expression were pooled and subjected to proteomic, pulsed-SILAC and phosphoproteomic analysis. Our fiber type-specific quantitative proteome analysis confirmed the distribution of fiber types in the soleus muscle, substantiates metabolic adaptions in oxidative and glycolytic fibers, and highlighted significant differences between the proteomes of type IIb fibers from different muscle groups, including a differential expression of desmin and actinin-3. A detailed map of the Lys-6 incorporation rates in muscle fibers showed an increased turnover of slow fibers compared to fast fibers. In addition, labeling of mitochondrial respiratory chain complexes revealed a broad range of Lys-6 incorporation rates, depending on the localization of the subunits within distinct complexes.
Project description:Phenotypic plasticity, the ability to switch between different morphological types, plays critical roles in environmental adaptation, leading to infections, and allowing for sexual reproduction in pathogenic Candida species. Candida tropicalis, which is both an emerging human fungal pathogen and an environmental fungus, can switch between two heritable cell types termed white and opaque. In this study, we report the discovery of a novel phenotype in C. tropicalis, named the gray phenotype. Similar to Candida albicans and Candida dubliniensis, white, gray, and opaque cell types of C. tropicalis also form a tristable switching system, where gray cells are relatively small and elongated. In C. tropicalis, gray cells exhibit intermediate levels of mating competency and virulence in a mouse systemic infection model compared to the white and opaque cell types, express a set of cell type-enriched genes, and exhibit both common and species-specific biological features. The key regulators of white-opaque transitions, Wor1 and Efg1, are not required for the gray phenotype. A comparative study of the gray phenotypes in C. tropicalis, C. albicans, and C. dubliniensis provides clues to explain the species differences in terms of virulence, ecological niches, and prevalence among these three species.
Project description:Introduction: The mouse skeletal muscle is composed of four distinct fiber types that differ in contractile function, number of mitochondria and metabolism. Every muscle group has a specific composition and distribution of the four fiber types. Until now, three genes (CnA, PGC1α and PPARδ) are identified that are involved in the generation of more oxidative muscle types. In the present study we searched for novel genes that are involved in specifying different muscle types. Methods: Gastrocnemius and quadriceps muscles were dissected from 20-week old C57BL/6J mice. Gene expression profiles were compared at the level of the whole-transcriptome. The diet-sensitivity of genes differentially expressed between muscle types was explored by comparing mice fed a low fat diet with mice fed a high fat diet. Results: We identified 162 differentially expressed genes in the gastrocnemius as compared with the quadriceps. Genes with the strongest regulations were markers for oxidative fiber types, Hoxd8, Hoxd9 and Hoxd10 and others involved in embryogenesis. Additionally, diet did not influence the expression levels of genes specifying muscle types. Finally, when extrapolating our data to the soleus we could not find a corresponding gene expression pattern between Hoxd8, Hoxd9 and any of the fiber-type specific markers. However, based on these gene expression patterns we could distinguish the gastrocnemius, quadriceps and soleus from each other. Conclusion: Hoxd genes and genes that are markers for the different fiber types specify muscle type in a diet-independent way The aim of the present study was to find novel genes that may play a role in specifying muscle types. Therefore we compared gene expression profiles of the gastrocnemius with the quadriceps at the level of the whole-transcriptome. Functional implications were assessed by the analyses of predefined gene sets based on Gene Ontology, biochemical, metabolic and signaling pathways. muscle-type comparison
Project description:Large White and Meishan pigs were either non-treated or injected with mammalian 1-24 ACTH (Immediate Synachten, Novartis France) at the dose of 250 µg per animal. Pigs were sacrificed either immediately after capture from their home cage (non-treated animals) or 1 hour following ACTH injection. Adrenal glands were immediately collected from pigs and frozen on dry ice and then stored at -80°C until RNA isolation. Keywords: stress response, adrenal, gene expression, pig
Project description:Muscle is highly hierarchically organized, with functions shaped by genetically controlled expression of protein ensembles with different isoform profiles at the sarcomere scale. However, it remains unclear how isoform profiles shape whole-muscle performance. We compared two mouse hindlimb muscles, the slow, relatively parallel-fibered soleus and the faster, more pennate-fibered tibialis anterior (TA), across scales: from gene regulation, isoform expression and translation speed, to force-length-velocity-power for intact muscles. Expression of myosin heavy-chain (MHC) isoforms directly corresponded with contraction velocity. The fast-twitch TA with fast MHC isoforms had faster unloaded velocities (actin sliding velocity, Vactin; peak fiber velocity, Vmax) than the slow-twitch soleus. For the soleus, Vactin was biased towards Vactin for purely slow MHC I, despite this muscle's even fast and slow MHC isoform composition. Our multi-scale results clearly identified a consistent and significant dampening in fiber shortening velocities for both muscles, underscoring an indirect correlation between Vactin and fiber Vmax that may be influenced by differences in fiber architecture, along with internal loading due to both passive and active effects. These influences correlate with the increased peak force and power in the slightly more pennate TA, leading to a broader length range of near-optimal force production. Conversely, a greater force-velocity curvature in the near-parallel fibered soleus highlights the fine-tuning by molecular-scale influences including myosin heavy and light chain expression along with whole-muscle characteristics. Our results demonstrate that the individual gene, protein and whole-fiber characteristics do not directly reflect overall muscle performance but that intricate fine-tuning across scales shapes specialized muscle function.