Coordinated patterns of gene expressions for adult muscle build-up in transgenic mice expressing myostatin propeptide

<p>Abstract</p> <p>Background</p> <p>Skeletal muscle growth and maintenance are essential for human health. One of the muscle regulatory genes, namely myostatin, a member of transforming growth factor-β, plays a dominant role in the genetic control of muscle mass. Myostatin is synthesized as a precursor protein, which generates the N-terminal propeptide and the C-terminal mature myostatin peptide by a post-translational cleavage event. Previously, transgenic over-expression of myostatin propeptide in skeletal muscle results in significant muscle growth in early stages of development. The objectives of present study were to further characterize muscle growth in later stages of life and to identify genes and their expression patterns that are responsible for adult muscle build-up by myostatin propeptide.</p> <p>Results</p> <p>Immunohistochemical staining with an antibody to the N-terminus indicates a high level of myostatin propeptide present in the muscles of transgenic mice while there were no apparent differences in myostatin protein distribution in the muscle fibers between the transgenic and wild-type mice. Main individual muscles increased by 76–152% in the transgenic mice over their wild-type littermate mice at 12 months of age. A large number of nuclei were localized in the central and basal lamina of the myofibers in the transgenic mice as the number of nuclei per fiber and 100 μm²area was significantly higher in transgenic mice than wild-type mice. By systemic comparisons of global mRNA expression patterns between transgenic mice and wild-type littermates using microarray and qRT-PCR techniques, we have identified distinct gene expression patterns to support adult muscle build-up by myostatin propeptide, which are comprised of enhanced expressions of myogenic regulatory factors and extracelullar matrix components, and differentially down-regulated expressions of genes related to protein degradation and mitochondrial ATP synthesis.</p> <p>Conclusion</p> <p>The results present a coordinated pattern of gene expressions for reduced energy utilization during muscle build-up in adult stage. Enhanced muscle buildup by myostatin propeptide is sustained by reduced ATP synthesis as a result of a decreased activity of protein degradation. Myostatin propeptide may have a therapeutic application to the treatment of clinical muscle wasting problems by depressing myostatin activity.</p

Identifications of SUMO-1 cDNA and Its Expression Patterns in Pacific White Shrimp Litopeanaeus vannamei

Small ubiquitin-like modifiers (SUMO) work in a similar way as ubiquitin to alter the biological properties of a target protein by conjugation. A shrimp SUMO cDNA named LvSUMO-1 was identified in Litopenaeus vannamei. LvSUMO-1 cDNA contains a coding sequence of 282 nucleotides with untranslated regions of 37 bp at 5'-end and 347 bp at 3'-end, respectively. The deduced 93 amino acids exhibit 83% identity with the Western Honeybee SUMO-1, and more than 65% homologies with human and mouse SUMO-1. LvSUMO-1 mRNA is expressed in most L. vannamei tissues with the highest level in hepatopancrease. The mRNA expression of LvSUMO-1 over development stages in L. Vammamei is distinguished by a low level in nauplius stage and relatively high level in postlarva stage with continuous expression until juvenile stage. The LvSUMO-1 protein and its conjugated proteins are detected in both cytoplasm and nucleus in several tissues. Interestingly, LvSUMO-1 mRNA levels are high in abdominal muscle during the premolt stage, wherein it has significant activities of protein degradation, suggesting its possible role in the regulation of shrimp muscle protein degradation

miRNA Transcriptome of Hypertrophic Skeletal Muscle with Overexpressed Myostatin Propeptide

MicroRNAs (miRNAs) play an imperative role in cell proliferation, differentiation, and cell metabolism through regulation of gene expression. Skeletal muscle hypertrophy that results from myostatin depression by its propeptide provides an interesting model to understand how miRNA transcriptome is involved in myostatin-based fiber hypertrophy. This study employed Solexa deep sequencing followed by Q-PCR methods to analyze miRNA transcriptome of skeletal muscle of myostatin propeptide transgenic mice in comparison with their littermate controls. A total of 461 mature known and 69 novel miRNAs were reported from this study. Fifty-seven miRNAs were expressed differentially between transgenic and littermate controls, of which most abundant miRNAs, miR-133a and 378a, were significantly differentially expressed. Expression profiling was validated on 8 known and 2 novel miRNAs. The miRNA targets prediction and pathway analysis showed that FST, SMAD3, TGFBR1, and AcvR1a genes play a vital role in skeletal muscle hypertrophy in the myostatin propeptide transgenic mice. It is predicted that miR-101 targeted to TGFBR1 and SMAD3, to AcvR2a and TGF-genes. In conclusion, the study offers initial miRNA profiling and methodology of miRNA targets prediction for myostatin-based hypertrophy. These differentially expressed miRNAs are proposed as candidate miRNAs for skeletal muscle hypertrophy

Molecular Characterizations of a Novel Putative DNA-Binding Protein LvDBP23 in Marine Shrimp L. vannamei Tissues and Molting Stages

Litopenaeus Vannamei, well known as pacific white shrimp, is the most popular shrimp in the world shrimp market. Identification and characterization of shrimp muscle regulatory genes are not only important for shrimp genetic improvement, but also facilitate comparative genomic tools for understanding of muscle development and regeneration.A novel mRNA encoding for a putative DNA-binding protein LvDBP23 was identified from Litopenaeus vannamei abdominal muscle cDNA library. The LvDBP23 cDNA contains 639 nucleotides of protein-coding sequence with deduced 212 amino acids of predicted molecular mass 23.32 kDa with glycine-rich domain at amino acid position 94-130. The mRNA sequence is successfully used for producing LvDBP23 recombinant protein in sf9 insect cell expression system. The expression of LvDBP23 mRNA is presented in abdominal muscle and swimming leg muscle, as well as other tissues including intestine, lymphoid and gill. The mRNA expression has the highest level in abdominal muscle in all tested tissues. LVDBP23 transcript during the molt cycle is highly expressed in the intermolt stage. In vitro nucleic acid-binding assays reveal that LvDBP23 protein can bind to both ssDNA and dsDNA, indicating its possible role of regulation of gene transcription.We are the first to report a DNA-binding protein identified from the abdominal muscle tissue of marine shrimp L. Vannamei. Its high-level specific expression during the intermot stage suggests its role in the regulation of muscle buildup during the growth phase of shrimp molt cycle

Uses of Papaya Leaf and Seaweed Supplementations for Controlling Glucose Homeostasis in Diabetes

Studies from laboratory animal models and complementary medical practices have implied that nutrients from special plants or herbs contain antidiabetic, antioxidant, anti-obese, anti-hypertensive, and anti-inflammatory properties. Seaweed and tropical papaya, which are widely available in Asian and Pacific countries, have been used as home remedies for centuries. The bioactive extracts from these plants contain vitamins A, C, B and E complexes, as well as polysaccharides, phenolic compounds, essential fatty acids, flavonoids, saponins, fucoidan, and phlorotannin. In this review, the authors examine the pathogenesis of diabetes characterized by hyperglycemia due to the dysregulation of glucose homeostasis, antidiabetic/antihyperglycemic seaweed or/and papaya derived bioactive phytochemicals and their proposed mechanisms of action in the management of Type 2 Diabetes Mellitus (T2DM). The authors also propose combining papaya and seaweed to enhance their antidiabetic effects, leveraging the advantages of herb-to-herb combination. Papaya and seaweed have demonstrated antidiabetic effects through in vitro assays, cellular models, and animal studies despite the limited clinical trials. Nutraceuticals with antidiabetic effects, such as secondary metabolites isolated from seaweed and papaya, could be combined for a synergistic effect on T2DM management. However, the application of these compounds in their purified or mixed forms require further scientific studies to evaluate their efficacy against diabetes-related complications, such as hyperlipidemia, elevated free radicals, pro-inflammatory molecules, insulin insensitivity, and the degeneration of pancreatic beta cells

Identifications of captive and wild tilapia species existing in Hawaii by mitochondrial DNA control region sequence.

BACKGROUND: The tilapia family of the Cichlidae includes many fish species, which live in freshwater and saltwater environments. Several species, such as O. niloticus, O. aureus, and O. mossambicus, are excellent for aquaculture because these fish are easily reproduced and readily adapt to diverse environments. Historically, tilapia species, including O. mossambicus, S. melanotheron, and O. aureus, were introduced to Hawaii many decades ago, and the state of Hawaii uses the import permit policy to prevent O. niloticus from coming into the islands. However, hybrids produced from O. niloticus may already be present in the freshwater and marine environments of the islands. The purpose of this study was to identify tilapia species that exist in Hawaii using mitochondrial DNA analysis. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we analyzed 382 samples collected from 13 farm (captive) and wild tilapia populations in Oahu and the Hawaii Islands. Comparison of intraspecies variation between the mitochondrial DNA control region (mtDNA CR) and cytochrome c oxidase I (COI) gene from five populations indicated that mtDNA CR had higher nucleotide diversity than COI. A phylogenetic tree of all sampled tilapia was generated using mtDNA CR sequences. The neighbor-joining tree analysis identified seven distinctive tilapia species: O. aureus, O. mossambicus, O. niloticus, S. melanotheron, O. urolepies, T. redalli, and a hybrid of O. massambicus and O. niloticus. Of all the populations examined, 10 populations consisting of O. aureus, O. mossambicus, O. urolepis, and O. niloticus from the farmed sites were relatively pure, whereas three wild populations showed some degree of introgression and hybridization. CONCLUSIONS/SIGNIFICANCE: This DNA-based tilapia species identification is the first report that confirmed tilapia species identities in the wild and captive populations in Hawaii. The DNA sequence comparisons of mtDNA CR appear to be a valid method for tilapia species identification. The suspected tilapia hybrids that consist of O. niloticus are present in captive and wild populations in Hawaii

The genetic distance between different populations based on mtDNA CR sequence.^*.

*<p>MtDNA CR genetic distances among different population were obtained by MEGA Version Data are presented by intraspecific or interspecific congeneric K2P-distances.</p

Genetic variability in captive and wild populations.^*.

*<p>N: the number of sequences; Pi: nucleotide diversity within the population; H: number of different sequences types; K: average number of nucleotide differences within the population.</p