RESUMO
INTRODUCTION: DNA methylation regulates exercise-induced changes in the skeletal muscle transcriptome. However, the specificity and the time course responses in the myogenic regulatory factors DNA methylation and mRNA expression after divergent exercise modes are unknown. PURPOSE: This study aimed to compare the time course changes in DNA methylation and mRNA expression for selected myogenic regulatory factors ( MYOD1 , MYF5 , and MYF6 ) immediately after, 4 h after, and 8 h after a single bout of resistance exercise (RE), high-intensity interval exercise (HIIE), and concurrent exercise (CE). METHODS: Nine healthy but untrained males (age, 23.9 ± 2.8 yr; body mass, 70.1 ± 14.9 kg; peak oxygen uptake [VÌO 2peak ], 41.4 ± 5.2 mL·kg -1 ·min -1 ; mean ± SD) performed a counterbalanced, randomized order of RE (4 × 8-12 repetition maximum), HIIE (12 × 1 min sprints at VÌO 2peak running velocity), and CE (RE followed by HIIE). Skeletal muscle biopsies (vastus lateralis) were taken before (REST) immediately (0 h), 4 h, and 8 h after each exercise bout. RESULTS: Compared with REST, MYOD1 , MYF5 , and MYF6 , mean methylation across all CpGs analyzed was reduced after 4 and 8 h in response to all exercise protocols ( P < 0.05). Reduced levels of MYOD1 methylation were observed after HIIE and CE compared with RE ( P < 0.05). Compared with REST, all exercise bouts increased mRNA expression over time ( MYOD1 at 4 and 8 h, and MYF6 at 4 h; P < 0.05). MYF5 mRNA expression was lower after 4 h compared with 0 h and higher at 8 h compared with 4 h ( P < 0.05). CONCLUSIONS: We observed an interrelated but not time-aligned response between the exercise-induced changes in myogenic regulatory factors demethylation and mRNA expression after divergent exercise modes. Despite divergent contractile stimuli, changes in DNA methylation and mRNA expression in skeletal muscle were largely confined to the late (4-8 h) recovery period and similar between the different exercise challenges.
Assuntos
Exercício Físico , Fatores de Regulação Miogênica , Masculino , Humanos , Adulto Jovem , Adulto , Fatores de Regulação Miogênica/genética , Fatores de Regulação Miogênica/metabolismo , Exercício Físico/fisiologia , Músculo Esquelético/fisiologia , RNA Mensageiro/metabolismo , DesmetilaçãoRESUMO
BACKGROUND: Myogenic regulatory factors (MRFs) such as MyoD, Myf6 and Myf5 play a vital role in the growth and development of muscles. Jeju Native Pig (JNP) is the top ranker in Korea amongst the indigenous livestock reared for meat purpose. Few studies covering transcript abundance of the MRFs and related to their co-expression with Pax7 in JNP have been conducted. Despite having better quality pork, JNP does not have a comparative growth rate with respect to western breeds. Therefore, the present study was designed with the objective to study the relative transcript levels of MRFs in the postnatal myogenesis of longissimus dorsi muscles in JNP and Berkshire breeds. RESULTS: Relative transcript levels were analyzed by qRT-PCR and blot expression analysis through Western blotting. Immunocytochemistry was performed to analyze their expressions at cellular levels. ToppCluster aided in the analysis of gene ontology of biological processes. The quantitative transcript levels of MyoD and Pax7 were significantly (P < 0.05) higher in Berkshire than in JNP. Myotube formation was observed under the co-expression of MyoD and Pax7. ToppCluster helped in the understanding of the linking of biological processes of the MRFs with the different signaling pathways. MyBPH had significantly (P < 0.05) high transcript levels during the chosen age groups in JNP than Berkshire. CONCLUSIONS: The current study can be helpful in understanding the genetic basis for myogenesis in postnatal stage. Moreover, it can act as stepping stone for the identification of marker genes related to body growth and meat quality in JNP.
Assuntos
Animais , Suínos , Fatores de Regulação Miogênica/metabolismo , Desenvolvimento Muscular/genética , Imuno-Histoquímica , Marcadores Genéticos , Western Blotting , Fatores de Regulação Miogênica/genética , Fator de Transcrição PAX7/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Ontologia Genética , Carne de PorcoRESUMO
Dynamin 2 (DNM2) is a ubiquitously expressed protein involved in many functions related to trafficking and remodeling of membranes and cytoskeleton dynamics. Mutations in the DNM2 gene cause the autosomal dominant centronuclear myopathy (AD-CNM), characterized mainly by muscle weakness and central nuclei. Several defects have been identified in the KI-Dnm2R465W/+ mouse model of the disease to explain the muscle phenotype, including reduction of the satellite cell pool in muscle, but the functional consequences of this depletion have not been characterized until now. Satellite cells (SC) are the main source for muscle growth and regeneration of mature tissue. Here, we investigated muscle regeneration in the KI-Dnm2R465W/+ mouse model for AD-CNM. We found a reduced number of Pax7-positive SCs, which were also less activated after induced muscle injury. The muscles of the KI-Dnm2R465W/+ mouse regenerated more slowly and less efficiently than wild-type ones, formed fewer new myofibers, and did not recover its normal mass 15 days after injury. Altogether, our data provide evidence that the muscle regeneration is impaired in the KI-Dnm2R465W/+ mouse and contribute with one more layer to the comprehension of the disease, by identifying a new pathomechanism linked to DNM2 mutations which may be involved in the muscle-specific impact occurring in AD-CNM.
Assuntos
Dinamina II/metabolismo , Músculo Esquelético/lesões , Miopatias Congênitas Estruturais/genética , Células Satélites de Músculo Esquelético/fisiologia , Animais , Dinamina II/genética , Regulação da Expressão Gênica , Técnicas de Introdução de Genes , Camundongos , Mutação , Fatores de Regulação Miogênica/genética , Fatores de Regulação Miogênica/metabolismo , RegeneraçãoRESUMO
Toxoplasma gondii is the causative agent of toxoplasmosis, a parasitic disease with a wide global prevalence. The parasite forms cysts in skeletal muscle cells and neurons, although no evident association with inflammatory infiltrates has been typically found. We studied the impact of T. gondii infection on the myogenic program of mouse skeletal muscle cells (SkMC). The C2C12 murine myoblast cell line was infected with T. gondii tachyzoites (ME49 strain) for 24 h followed by myogenic differentiation induction. T. gondii infection caused a general decrease in myotube differentiation, fusion and maturation, along with decreased expression of myosin heavy chain. The expression of Myogenic Regulatory Factors Myf5, MyoD, Mrf4 and myogenin was modulated by the infection. Infected cultures presented increased proliferation rates, as assessed by Ki67 immunostaining, whereas neither host cell lysis nor apoptosis were significantly augmented in infected dishes. Cytokine Bead Array indicated that IL-6 and MCP-1 were highly increased in the medium from infected cultures, whereas TGF-ß1 was consistently decreased. Inhibition of the IL-6 receptor or supplementation with recombinant TGF-ß failed to reverse the deleterious effects caused by the infection. However, conditioned medium from infected cultures inhibited myogenesis in C2C12 cells. Activation of the Wnt/ß-catenin pathway was impaired in T. gondii-infected cultures. Our data indicate that T. gondii leads SkMCs to a pro-inflammatory phenotype, leaving cells unresponsive to ß-catenin activation, and inhibition of the myogenic differentiation program. Such deregulation may suggest muscle atrophy and molecular mechanisms similar to those involved in myositis observed in human patients.
Assuntos
Interações Hospedeiro-Patógeno , Desenvolvimento Muscular , Fatores de Regulação Miogênica/metabolismo , Toxoplasma/fisiologia , Toxoplasmose/metabolismo , Animais , Biomarcadores , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Imunofluorescência , Expressão Gênica , Genes Reporter , Camundongos , Mioblastos Esqueléticos/metabolismo , Mioblastos Esqueléticos/parasitologia , Fatores de Regulação Miogênica/genética , Toxoplasmose/parasitologia , Via de Sinalização WntRESUMO
The aim of this study was to examine the activation of skeletal muscle signaling pathways related to protein synthesis and the gene expression of regeneration/degradation markers following repeated bouts of eccentric cycling. Nine untrained men (25.4 ± 1.9 yr) performed two 30-min eccentric cycling bouts (ECC1, ECC2) at 85% of maximal concentric workload, separated by 2 wk. Muscle biopsies were taken from the vastus lateralis before and 2 h after each bout. Indirect markers of muscle damage were assessed before and 24-48 h after exercise. Changes in the Akt/mammalian target of rapamycin (mTOR)/rbosomal protein S6 kinase 1 (S6K1)/ribosomal protein S6 (rpS6) and MAPK signaling pathways were measured by Western blot and changes in mRNA expression of IL-6 and IL-1ß, and myogenic regulatory factors (MRFs) were measured by real-time PCR. ECC1 induced greater increases in indirect markers of muscle damage compared with ECC2. Phosphorylation of S6K1 and rpS6 increased after both exercise bouts (P < 0.05), whereas phosphorylation of mTOR increased after ECC2 only (P = 0.03). Atrogin-1 mRNA expression decreased after ECC1 and ECC2 (P < 0.05) without changes in muscle RING-finger protein-1 mRNA. Basal mRNA levels of myoblast determination protein-1 (MyoD), MRF4, and myogenin were higher 2 wk after ECC1 (P < 0.05). MRF4 mRNA increased after ECC1 and ECC2 (P < 0.05), whereas MyoD mRNA expression increased only after ECC1 (P = 0.03). Phosphorylation of JNK and p38 MAPK increased after both exercise bouts (P < 0.05), similar to IL-6 and IL-1ß mRNA expression. All together, these results suggest that differential regulation of the mTOR pathway and MRF expression could mediate the repeated bout effect observed between an initial and secondary bout of eccentric exercise.
Assuntos
Ciclismo , Exercício Físico/fisiologia , Expressão Gênica , Sistema de Sinalização das MAP Quinases/genética , Biossíntese de Proteínas/genética , Músculo Quadríceps/metabolismo , Regeneração/genética , Adulto , Humanos , Interleucina-1beta/genética , Interleucina-6/genética , MAP Quinase Quinase 4/metabolismo , Masculino , Proteínas Musculares/genética , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Proteína MyoD/genética , Fatores de Regulação Miogênica/genética , Miogenina/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteína S6 Ribossômica/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Proteínas Ligases SKP Culina F-Box/genética , Serina-Treonina Quinases TOR/metabolismo , Proteínas com Motivo Tripartido/genética , Ubiquitina-Proteína Ligases/genética , Adulto Jovem , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Ki-1/57 is a nuclear and cytoplasmic regulatory protein first identified in malignant cells from Hodgkin's lymphoma. It is involved in gene expression regulation on both transcriptional and mRNA metabolism levels. Ki-1/57 belongs to the family of intrinsically unstructured proteins and undergoes phosphorylation by PKC and methylation by PRMT1. Previous characterization of its protein interaction profile by yeast two-hybrid screening showed that Ki-1/57 interacts with proteins of the SUMOylation machinery, the SUMO E2 conjugating enzyme UBC9 and the SUMO E3 ligase PIAS3, which suggested that Ki-1/57 could be involved with this process. Here we identified seven potential SUMO target sites (lysine residues) on Ki-1/57 sequence and observed that Ki-1/57 is modified by SUMO proteins in vitro and in vivo. We showed that SUMOylation of Ki-1/57 occurred on lysines 213, 276, and 336. In transfected cells expressing FLAG-Ki-1/57 wild-type, its paralog FLAG-CGI-55 wild-type, or their non-SUMOylated triple mutants, the number of PML-nuclear bodies (PML-NBs) is reduced compared with the control cells not expressing the constructs. More interestingly, after treating cells with arsenic trioxide (As2O3), the number of PML-NBs is no longer reduced when the non-SUMOylated triple mutant Ki-1/57 is expressed, suggesting that the SUMOylation of Ki-1/57 has a role in the control of As2O3-induced PML-NB formation. A proteome-wide analysis of Ki-1/57 partners in the presence of either SUMO-1 or SUMO-2 suggests that the involvement of Ki-1/57 with the regulation of gene expression is independent of the presence of either SUMO-1 or SUMO-2; however, the presence of SUMO-1 strongly influences the interaction of Ki-1/57 with proteins associated with cellular metabolism, maintenance, and cell cycle.
Assuntos
Fatores de Regulação Miogênica/metabolismo , Mapeamento de Interação de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA/metabolismo , Proteína SUMO-1/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Trióxido de Arsênio , Arsenicais/farmacologia , Ciclo Celular/genética , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Núcleo Celular/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Células HEK293 , Células HeLa , Humanos , Lisina , Fatores de Regulação Miogênica/genética , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Óxidos/farmacologia , Plasmídeos/química , Plasmídeos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , Proteínas de Ligação a RNA/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína SUMO-1/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Sumoilação , Transcrição GênicaRESUMO
MyoD and MyoG are transcription factors that have essential roles in myogenic lineage determination and muscle differentiation. The purpose of this study was to compare multiple amino acid sequences of myogenic regulatory proteins to infer evolutionary relationships among chordates. Protein sequences from Mus musculus (P10085 and P12979), human Homo sapiens (P15172 and P15173), bovine Bos taurus (Q7YS82 and Q7YS81), wild pig Sus scrofa (P49811 and P49812), quail Coturnix coturnix (P21572 and P34060), chicken Gallus gallus (P16075 and P17920), rat Rattus norvegicus (Q02346 and P20428), domestic water buffalo Bubalus bubalis (D2SP11 and A7L034), and sheep Ovis aries (Q90477 and D3YKV7) were searched from a non-redundant protein sequence database UniProtKB/Swiss-Prot, and subsequently analyzed using the Mega6.0 software. MyoD evolutionary analyses revealed the presence of three main clusters with all mammals branched in one cluster, members of the order Rodentia (mouse and rat) in a second branch linked to the first, and birds of the order Galliformes (chicken and quail) remaining isolated in a third. MyoG evolutionary analyses aligned sequences in two main clusters, all mammalian specimens grouped in different sub-branches, and birds clustered in a second branch. These analyses suggest that the evolution of MyoD and MyoG was driven by different pathways.
Assuntos
Cordados/genética , Evolução Molecular , Proteína MyoD/genética , Fatores de Regulação Miogênica/genética , Animais , Diferenciação Celular , Cordados/classificação , Bases de Dados de Proteínas , Humanos , Filogenia , Análise de Sequência de ProteínaRESUMO
INTRODUCTION: Burn injury (BI) greater than 40% has been associated with protein catabolism and it is characterized by a hypermetabolic response followed for muscle loss. OBJECTIVE: The purpose of this study was to investigate the temporal effects of extensive experimental BI in the skeletal muscle distant from lesion, through morphological analysis, expression of genes related to muscle atrophy, inflammation and the myogenic regulatory factors. MATERIALS AND METHODS: A total of 60 young male wistar rats were distributed into two groups, control (C) and subjected to scald burn injury (SBI). The animals were euthanized 1, 4 and 14 days post-sham or 45% of the total body surface BI. The medial head of gastrocnemii muscles were submitted to histopathological, morphometric (muscle fibers area and density), MyoD and myogenin immunoexpression, and gene expression for TNF-α, iNOS and E3 ubiquitin ligases (MuRF1 and MAFbx). RESULTS: Histopathological findings were consistent with increased amount of connective tissue and inflammatory process. Muscle fiber area of SBI groups was smaller than C and no differences were found in fiber muscle density. TNF-α was higher in SBI groups, one and 14 days post-injury; iNOS expression was higher on the first and fourth day post-injury. MuRF-1 was higher on the day four and MAFbx on the day 14. CONCLUSION: In conclusion, BI causes inflammation, atrophy and myogenesis stimulation in muscle as a result of systemic host response.
Assuntos
Queimaduras/complicações , Inflamação/etiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/etiologia , Fatores de Regulação Miogênica/metabolismo , Animais , Inflamação/metabolismo , Inflamação/patologia , Masculino , Camundongos , Modelos Animais , Fibras Musculares Esqueléticas/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Proteína MyoD/metabolismo , Miogenina/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Ratos Wistar , Fator de Necrose Tumoral alfa/metabolismo , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Skeletal muscle growth in the pirarucu (Arapaima gigas) is highly interesting to fish farmers because it provides information about how the mechanism in muscle mass increase, characteristic of the pecies, is regulated. Pirarucu has specific muscle growth that highlights the speciess significance and commercial value. Current research evaluates the morphology and the growth-related gene expression in the red and white skeletal muscles of the pirarucu. Muscle samples were collected from the lateral anterior region and frozen in liquid nitrogen. Histological sections were performed and stained by HE for morphological analysis. Red and white muscle samples were used to determine MyoD, myogenin, and myostatin genes expression by Real-time Polymerase Chain Reaction. Although MyoD and myogenin were not statistically different in the two types of muscles, myostatin was significantly higher in the white rather than in the red muscle. Results show the muscle growth characteristics of the species and may be helpful for improving aquaculture management programs.
A caracterização do crescimento muscular no pirarucu (Arapaima gigas) é de elevado interesse para os piscicultores, pois fornece informações de extrema importância sobre como esse mecanismo é regulado e permite o rápido aumento na massa muscular característico da espécie. O pirarucu possui um crescimento muscular típico, o que destaca sua importância e seu valor comercial. O objetivo do presente trabalho foi avaliar a morfologia e a expressão de genes relacionados ao crescimento da musculatura esquelética vermelha e branca do pirarucu. As amostras de músculo vermelho e branco foram obtidas da região lateral anterior superficial e profunda, respectivamente, e estas foram congeladas em nitrogênio líquido. Para análise morfológica, cortes histológicos obtidos em criostato foram submetidos à coloração com HE. A expressão dos genes MyoD, miogenina e miostatina foi feita por PCR em tempo real após transcrição reversa (RT-qPCR). Em relação à expressão de MyoD e miogenina, não houve diferença estatística na comparação entre os músculos; por outro lado, a expressão da miostatina foi significativamente maior no músculo branco, em comparação com o músculo vermelho. Estes resultados refletem as características de crescimento muscular do pirarucu e podem ser úteis na tentativa de melhorar as condições de criação e a sobrevivência da espécie.
Assuntos
Animais , Caraciformes/crescimento & desenvolvimento , Caraciformes/genética , Expressão Gênica , Fatores de Regulação Miogênica , Reação em Cadeia da PolimeraseRESUMO
Skeletal muscle growth in the pirarucu (Arapaima gigas) is highly interesting to fish farmers because it provides information about how the mechanism in muscle mass increase, characteristic of the pecies, is regulated. Pirarucu has specific muscle growth that highlights the speciess significance and commercial value. Current research evaluates the morphology and the growth-related gene expression in the red and white skeletal muscles of the pirarucu. Muscle samples were collected from the lateral anterior region and frozen in liquid nitrogen. Histological sections were performed and stained by HE for morphological analysis. Red and white muscle samples were used to determine MyoD, myogenin, and myostatin genes expression by Real-time Polymerase Chain Reaction. Although MyoD and myogenin were not statistically different in the two types of muscles, myostatin was significantly higher in the white rather than in the red muscle. Results show the muscle growth characteristics of the species and may be helpful for improving aquaculture management programs.(AU)
A caracterização do crescimento muscular no pirarucu (Arapaima gigas) é de elevado interesse para os piscicultores, pois fornece informações de extrema importância sobre como esse mecanismo é regulado e permite o rápido aumento na massa muscular característico da espécie. O pirarucu possui um crescimento muscular típico, o que destaca sua importância e seu valor comercial. O objetivo do presente trabalho foi avaliar a morfologia e a expressão de genes relacionados ao crescimento da musculatura esquelética vermelha e branca do pirarucu. As amostras de músculo vermelho e branco foram obtidas da região lateral anterior superficial e profunda, respectivamente, e estas foram congeladas em nitrogênio líquido. Para análise morfológica, cortes histológicos obtidos em criostato foram submetidos à coloração com HE. A expressão dos genes MyoD, miogenina e miostatina foi feita por PCR em tempo real após transcrição reversa (RT-qPCR). Em relação à expressão de MyoD e miogenina, não houve diferença estatística na comparação entre os músculos; por outro lado, a expressão da miostatina foi significativamente maior no músculo branco, em comparação com o músculo vermelho. Estes resultados refletem as características de crescimento muscular do pirarucu e podem ser úteis na tentativa de melhorar as condições de criação e a sobrevivência da espécie.(AU)