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1.
Yi Chuan ; 41(12): 1110-1118, 2019 Dec 20.
Artigo em Chinês | MEDLINE | ID: mdl-31857282

RESUMO

Myogenesis is a complex physiological process that is mainly involved in the proliferation of myogenic stem cells to form myoblasts, which then differentiated and fused to form multinucleated myotubes. Many proteins have been found to be involved in myoblast fusion, but none of them are muscle-specific fusion proteins. In recent years, two muscle-specific transmembrane proteins, i.e. Myomaker and Myomerger, have been discovered and identified, which can coordinate and promote the fusion of myoblasts and thus participate in the process of myogenesis. In this review, we summarize the research progress of Myomaker and Myomerger in myogenesis, including their expression patterns and functional domains, as well as their participation in myoblast fusion mechanisms, aiming to provide relevant ideas for in-depth study of the myogenesis process and treatment of diseases related to myoblast fusion.


Assuntos
Proteínas de Membrana , Músculo Esquelético , Mioblastos , Animais , Diferenciação Celular , Fusão Celular , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Desenvolvimento Muscular , Proteínas Musculares , Músculo Esquelético/citologia , Mioblastos/citologia
2.
Yi Chuan ; 41(12): 1119-1128, 2019 Dec 20.
Artigo em Chinês | MEDLINE | ID: mdl-31857283

RESUMO

Porcine skeletal muscle development is a complex biological process, and differentiation of skeletal muscle satellite cells is an important part of skeletal muscle development. In recent years, it has been found that lncRNA plays an important role in the differentiation of skeletal muscle satellite cells. Here we investigate the effect of lncRNA TCONS_00815878 on the differentiation of porcine skeletal muscle satellite cells. We first used qRT-PCR to detect the expression levels of TCONS_00815878 in six tissues (heart, spleen, lung, kidney, back muscles and leg muscles) of Yorkshire piglets within seven days of birth. At the same time, the expression levels of TCONS_00815878 at five different time points from the embryonic stage to the postnatal stage (35 d, 45 d, 55 d of embryos, and 7 d, 200 d of postpartum leg muscles) were examined. The expression of the differentiation marker genes MyoD, MyoG and MyHC was examined by knocking down TCONS_00815878 in porcine skeletal muscle satellite cells using antisense oligonucleotides (ASO). The target gene of TCONS_00815878 was predicted by bioinformatics analysis, and the function and pathway of its target gene were predicted online using DAVID software. The results showed that TCONS_00815878 had the highest expression level in pig myocardium and leg muscles. Within seven days after birth, TCONS_00815878 increased in the muscle tissue of pigs, and reached the peak of expression level on the 7th day. During the process of proliferation and differentiation of porcine skeletal muscle satellite cells, the expression level of TCONS_00815878 increased during the differentiation stage and peaked at 30 h of differentiation. After knocking down TCONS_00815878, the expression levels of MyoD, MyoG and MyHC were decreased, but the expression level of MyoD was significantly decreased (P<0.05). In addition, functional predictions revealed that the target gene of TCONS_00815878 is enriched in multiple biological processes, such as glycolysis and pyruvate metabolism, related to skeletal muscle satellite cell differentiation. This study speculates that lncRNA TCONS_00815878 may promote the differentiation of porcine skeletal muscle satellite cells.


Assuntos
Diferenciação Celular , Regulação da Expressão Gênica no Desenvolvimento , Músculo Esquelético , RNA Longo não Codificante , Células Satélites de Músculo Esquelético , Animais , Diferenciação Celular/genética , Proliferação de Células , Células Cultivadas , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Desenvolvimento Muscular , Músculo Esquelético/citologia , RNA Longo não Codificante/genética , Células Satélites de Músculo Esquelético/citologia , Suínos
3.
Life Sci ; 236: 116906, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614147

RESUMO

AIMS: The anti-hyperglycemic action of metformin on skeletal muscles is presently unclear. Long noncoding RNAs (lncRNAs) are implicated in multiple cellular functions. This study aims to explore the role of lncRNAs in the glucometabolic action of metformin on skeletal muscle cells. MAIN METHODS: Metformin accumulation was assessed using [14C]-metformin. A lncRNA array was used to investigate metformin-regulated lncRNAs in C2C12 skeletal muscle cells. Knockdown studies were applied to evaluate the function of lncRNA Dreh. A colorimetric assay was used for the measurement of medium glucose concentration; glucose transport was assessed using [3H]-2-deoxyglucose; real-time PCR was used for RNA expression analysis, and western blotting was used to assess protein expression in myotubes. A Dreh overexpression plasmid was transfected into the cells. KEY FINDINGS: Metformin accumulated in C2C12 myotubes. Metformin reduced medium glucose concentration and repressed lncRNA Dreh expression in the myotubes. Knockdown of Dreh in the myotubes resulted in reduced glucose concentration in the culture medium, increased glucose transport, and increased levels of GLUT4 protein in the plasma membrane. Overexpression of Dreh attenuated the glucose-lowering effect of metformin in myotubes. SIGNIFICANCE: The glucoregulatory actions of metformin are mediated in part by a lncRNA, Dreh, in the skeletal muscle cells. Dreh is a novel regulator for glucose transport and could be a therapeutic target for diabetes.


Assuntos
Glucose/metabolismo , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , RNA Longo não Codificante/genética , Animais , Transporte Biológico , Linhagem Celular , Regulação da Expressão Gênica , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Camundongos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos
4.
BMC Complement Altern Med ; 19(1): 287, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31660942

RESUMO

BACKGROUND: Sarcopenia, the decline of skeletal muscle tissue attributed to primary aging is a major concern in older adults. Flavonoids might have potential benefits by modulating the regulation of satellite cells, thus preventing muscle loss. Sinensetin (SIN), a citrus methylated flavone with anti-inflammatory and anti-proliferative activity, can enhance lipolysis. The objective of the present study was to investigate whether SIN might have sarcopenia-suppressing effect on satellite cells from thigh and calf muscle tissues of young and old rats. METHODS: Primary muscle cells were obtained from thigh and calf tissues of young and old group rats by dissection. Obtained satellite cells were incubated with indicated concentrations of SIN (50 and 100 µM) treated and untreated condition in differentiation medium. Morphological changes of cells were examined using a phase-contrast microscope. Protein expression levels of myoD and myogenin were analyzed by Western blot. Cells treated with or without SIN under differentiation condition were also immunocytochemically stained for myogenin and 4',6-diamidino-2-phenylindole (DAPI). RESULTS: Morphologically, the differentiation extracted satellite cells was found to be more evident in SIN treated group of aged rat's cells than that in SIN untreated group. Expression levels of myoD and myogenin proteins involved in myogenesis were increased upon treatment with SIN. CONCLUSIONS: Collectively, our results indicate that SIN can alleviate age-related sarcopenia by increasing differentiation rate and protein levels of myoD and myogenin.


Assuntos
Envelhecimento/efeitos dos fármacos , Flavonoides/farmacologia , Células Musculares/efeitos dos fármacos , Sarcopenia/tratamento farmacológico , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Células Cultivadas , Humanos , Masculino , Células Musculares/metabolismo , Desenvolvimento Muscular/efeitos dos fármacos , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Proteína MyoD/genética , Proteína MyoD/metabolismo , Miogenina/genética , Miogenina/metabolismo , Ratos , Ratos Sprague-Dawley
5.
Genes Dev ; 33(23-24): 1635-1640, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624084

RESUMO

Short tandem repeats (STRs) are prone to expansion mutations that cause multiple hereditary neurological and neuromuscular diseases. To study pathomechanisms using mouse models that recapitulate the tissue specificity and developmental timing of an STR expansion gene, we used rolling circle amplification and CRISPR/Cas9-mediated genome editing to generate Dmpk CTG expansion (CTGexp) knockin models of myotonic dystrophy type 1 (DM1). We demonstrate that skeletal muscle myoblasts and brain choroid plexus epithelial cells are particularly susceptible to Dmpk CTGexp mutations and RNA missplicing. Our results implicate dysregulation of muscle regeneration and cerebrospinal fluid homeostasis as early pathogenic events in DM1.


Assuntos
Processamento Alternativo/genética , Repetições de Microssatélites/genética , Músculo Esquelético/fisiopatologia , Distrofia Miotônica/genética , Distrofia Miotônica/fisiopatologia , Processamento de RNA/genética , Regiões 3' não Traduzidas/genética , Animais , Plexo Corióideo/fisiopatologia , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Introdução de Genes , Camundongos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/patologia , Músculo Esquelético/citologia , Mutação , Miotonina Proteína Quinase/genética , Miotonina Proteína Quinase/metabolismo , Proteínas de Ligação a RNA/genética
6.
Adv Exp Med Biol ; 1169: 179-193, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31487024

RESUMO

Tissue-specific stem cells contribute to adult tissue maintenance, repair, and regeneration. In skeletal muscle, many different mononuclear cell types are capable of giving rise to differentiated muscle. Of these tissue stem-like cells, satellite cells (SCs) are the most studied muscle stem cell population and are widely considered the main cellular source driving muscle repair and regeneration in adult tissue. Within the satellite cell pool, many distinct subpopulations exist, each exhibiting differential abilities to exit quiescence, expand, differentiate, and self-renew. In this chapter, we discuss the different stem cell types that can give rise to skeletal muscle tissue and then focus on satellite cell heterogeneity during the process of myogenesis/muscle regeneration. Finally, we highlight emerging opportunities to better characterize muscle stem cell heterogeneity, which will ultimately deepen our appreciation of stem cells in muscle development, repair/regeneration, aging, and disease.


Assuntos
Músculo Esquelético , Células-Tronco , Adulto , Diferenciação Celular , Humanos , Desenvolvimento Muscular , Músculo Esquelético/citologia , Células-Tronco/citologia
7.
Muscle Nerve ; 60(4): 474-483, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31365129

RESUMO

INTRODUCTION: Poor recovery following nerve repair is due to progressive temporal loss of muscle function. Follistatin (FS), a glycoprotein with anabolic properties, may enhance muscle recovery following reinnervation. METHODS: Seventy-two male Sprague-Dawley rats underwent temporary (3 or 6 month) denervation or sham denervation. After reinnervation, rats were administered adeno-associated viral vectors expressing FS deoxyribonucleic acid (isoform FS-317) injected into the target muscle or sham treatment. Final assessment included muscle function testing, muscle histomorphology, nerve histomorphology, and FS protein quantification. RESULTS: FS improved muscle mass and type IIB muscle fiber size, and increased G-ratios and mean axon diameter in the 6-month temporary denervation group (P < .05). Elevated FS protein levels were detected in treated muscle (P < .05). FS increased satellite cell counts following temporary denervation and repair (P < .05). DISCUSSION: FS treatment had anabolic, neurotrophic, and satellite cell stimulatory effects when administered following prolonged (6-month) temporary denervation and repair.


Assuntos
Folistatina/genética , Denervação Muscular , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Recuperação de Função Fisiológica/genética , Nervo Tibial/cirurgia , Animais , Contagem de Células , Dependovirus , Técnicas de Transferência de Genes , Vetores Genéticos , Força Muscular/genética , Músculo Esquelético/citologia , Músculo Esquelético/inervação , Cadeias Pesadas de Miosina/metabolismo , Ratos , Ratos Sprague-Dawley , Células Satélites de Músculo Esquelético/citologia , Nervo Tibial/metabolismo , Nervo Tibial/patologia
8.
Cells ; 8(7)2019 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-31261950

RESUMO

Accumulating studies report that microRNAs (miRNAs) are actively involved in skeletal myogenesis. Previously, our study revealed that miR-146b-3p was related to the growth of skeletal muscle. Here, we further report that miR-146b-3p is essential for the proliferation, differentiation, and apoptosis of chicken myoblast. Elevated expression of miR-146b-3p can dramatically suppress proliferation and differentiation, and facilitate apoptosis of chicken myoblast. Besides, we identified two target genes of miR-146b-3p, AKT1 and MDFIC, and found that miR-146b-3p can inhibit the PI3K/AKT pathway. Our study also showed that both AKT1 and MDFIC can promote the proliferation and differentiation while inhibit the apoptosis of myoblast in chicken. Overall, our results demonstrate that miR-146b-3p, directly suppressing PI3K/AKT pathway and MDFIC, acts in the proliferation, differentiation, and apoptosis of myoblast in chicken.


Assuntos
MicroRNAs/metabolismo , Desenvolvimento Muscular/genética , Mioblastos/fisiologia , Fatores de Regulação Miogênica/genética , Proteínas Proto-Oncogênicas c-akt/genética , Animais , Apoptose/genética , Diferenciação Celular/genética , Proliferação de Células/genética , Embrião de Galinha , Regulação da Expressão Gênica no Desenvolvimento , Músculo Esquelético/citologia , Músculo Esquelético/embriologia , Fatores de Regulação Miogênica/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Cultura Primária de Células , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/genética
9.
Life Sci ; 233: 116699, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31356902

RESUMO

AIMS: Skeletal muscle wasting is associated with many chronic diseases. Effective prevention and treatment of muscle wasting remain as a challenging task due to incomplete understanding of mechanisms by which muscle mass is maintained and regulated. This study investigated the functional role of Ubiquitin C-terminal hydrolase L1 (UCHL1) in skeletal muscle. MAIN METHODS: Mice with skeletal muscle specific gene knockout of UCHL1 and C2C12 myoblast cells with UCHL1 knockdown were used. Muscle fiber types and size were measured using tissue or cell staining. The mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 activities were assessed with the phosphorylation of their downstream targets. KEY FINDINGS: In mouse skeletal muscle, UCHL1 was primarily expressed in slow twitch muscle fibers. Mice with skeletal muscle specific knockout (skmKO) of UCHL1 exhibited enlarged muscle fiber sizes in slow twitch soleus but not fast twitch extensor digitorum longus (EDL) muscle. Meanwhile, UCHL1 skmKO enhanced mTORC1 activity and reduced mTORC2 activity in soleus but not in EDL. Consistently, in C2C12 cells, UCHL1 knockdown increased the myotube size, enhanced mTORC1 activity, and reduced mTORC2 activities as compared with control cells. UCHL1 knockdown did not change the major proteins of mTOR complex but decreased the protein turnover of PRAS40, an inhibitory factor of mTORC1. SIGNIFICANCE: These data revealed a novel function of UCHL1 in regulation of mTORC1 activity and skeletal muscle growth in slow twitch skeletal muscle. Given the upregulation of UCHL1 in denervation and spinal muscle atrophy, our finding advances understanding of regulators that are involved in muscle wasting.


Assuntos
Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Fibras Musculares de Contração Lenta/fisiologia , Músculo Esquelético/fisiologia , Atrofia Muscular/fisiopatologia , Mioblastos/fisiologia , Ubiquitina Tiolesterase/fisiologia , Animais , Células Cultivadas , Feminino , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Camundongos , Camundongos Knockout , Fibras Musculares de Contração Lenta/citologia , Músculo Esquelético/citologia , Atrofia Muscular/metabolismo , Mioblastos/citologia , Fosforilação , Ubiquitina Tiolesterase/antagonistas & inibidores
10.
Biosci Biotechnol Biochem ; 83(10): 1851-1857, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31159662

RESUMO

Several food constituents augment exercise-induced muscle strength improvement; however, the detailed mechanism underlying these combined effects is unknown because of the lack of a cultured cell model for evaluating the contraction-induced muscle protein synthesis level. Here, we aimed to establish a new in vitro muscle contraction model for analyzing the activation of mammalian target of rapamycin complex 1 (mTORC1) signaling. We adopted the tetanic electric stimulation of 50 V at 100 Hz for 10 min in L6.C11 myotubes. Akt, ERK1/2, and p70S6K phosphorylation increased significantly after electrical pulse stimulation (EPS), compared to untreated cells. Next, we used this model to analyze mTORC1 signaling in combination with exercise and beta-hydroxy-beta-methylbutyrate (HMB), an l-leucine metabolite. p70S6K phosphorylation increased significantly in the EPS+HMB group compared to that in the EPS-alone group. These findings show that our model could be used to analyze mTORC1 signaling and that HMB enhances muscle contraction-activated mTORC1 signaling.


Assuntos
Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Músculo Esquelético/efeitos dos fármacos , Transdução de Sinais , Valeratos/administração & dosagem , Animais , Linhagem Celular , Estimulação Elétrica , Técnicas In Vitro , L-Lactato Desidrogenase/metabolismo , Contração Muscular , Músculo Esquelético/citologia , Músculo Esquelético/enzimologia , Músculo Esquelético/fisiologia , Ratos
11.
Growth Horm IGF Res ; 46-47: 24-35, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31158782

RESUMO

OBJECTIVE: The objective of our study was to examine the direct action of insulin-like growth factor-1(IGF-1) signaling on energy homeostasis in myocytes. DESIGN: We studied the IGF-1 stimulation of mitochondrial uncoupling protein 3 (UCP3) expression in the HEK 293 derived cell line TSA201, murine C2C12 skeletal muscle myoblasts, and rat L6 skeletal myoblasts. We also investigated the direct effect of IGF-1 on the Insulin/IGF-1 receptor (IGF-1R)/phosphatidylinositol 3 (PI3)-Akt/forkhead box O4 (FOXO4) pathway using a combination of a reporter assay, semi-quantitative polymerase chain reaction, western blotting, and animal experiments. RESULTS: We demonstrated that IGF-1 regulates UCP3 expression via phosphorylation of FOXO4, which is a downstream signal transducer of IGF-1. UCP3 expression increased with activated FOXO4 in a dose-dependent manner. We also examined the functional FOXO4 binding site consensus sequences and identified it as the -1922 bp site in the UCP3 promoter region. UCP3 was also found to be concomitantly expressed with IGF-1 during differentiation of C2C12 myoblasts. Our animal experiments showed that high fat diet induced IGF-1 levels which likely influenced UCP3 expression in the skeletal muscle. CONCLUSION: Our findings demonstrate that that IGF-1 directly stimulates UCP3 expression via the IGF-1/IGF-1R/PI3-Akt/FOXO4 pathway.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/farmacologia , Músculo Esquelético/metabolismo , Mioblastos Esqueléticos/metabolismo , Proteína Desacopladora 3/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Diferenciação Celular , Fatores de Transcrição Forkhead/genética , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Mioblastos Esqueléticos/citologia , Mioblastos Esqueléticos/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Proteína Desacopladora 3/genética
12.
Anim Sci J ; 90(8): 1042-1049, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31237073

RESUMO

Glycogen synthase kinase beta (GSK3ß) plays an important role in skeletal muscle growth, regeneration, and repair. However, the mechanism of GSK3ß regulating MyHC2a expression is currently not clear. In this study, GSK3ß inhibition promoted skeletal muscle satellite cells (SMSCs) differentiation and increased expression of MyoD, MyoG, MyHC1, and MyHC2a genes. Then we cloned approximately 1.1 kb of goat MyHC2a gene promoter. The deletion fragment (-514/+55) of MyHC2a promoter exhibited the highest level of promoter activity, and a NFATc2 element in this region was responsible for MyHC2a promoter activity. Treatment of SB216713 significantly decreased the transcriptional activity of the fragment (-514/+55). Furthermore, GSK3ß inhibition had no effect on the luciferase activity of MyHC2a promoter after mutating the NFATc2-binding site. These results demonstrated that GSK3ß inhibition promoted SMSCs differentiation and regulated the MyHC2a gene expression through NFATc2 in goat-differentiated SMSCs.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/genética , Expressão Gênica/genética , Glicogênio Sintase Quinase 3 beta/antagonistas & inibidores , Glicogênio Sintase Quinase 3 beta/fisiologia , Músculo Esquelético/citologia , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Células Satélites de Músculo Esquelético/metabolismo , Animais , Diferenciação Celular/genética , Células Cultivadas , Feminino , Cabras , Luciferases/metabolismo , Fatores de Transcrição NFATC
13.
Nat Commun ; 10(1): 2576, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189900

RESUMO

Mitochondrial quality control is essential in highly structured cells such as neurons and muscles. In skeletal muscle the mitochondrial fission proteins are reduced in different physiopathological conditions including ageing sarcopenia, cancer cachexia and chemotherapy-induced muscle wasting. However, whether mitochondrial fission is essential for muscle homeostasis is still unclear. Here we show that muscle-specific loss of the pro-fission dynamin related protein (DRP) 1 induces muscle wasting and weakness. Constitutive Drp1 ablation in muscles reduces growth and causes animal death while inducible deletion results in atrophy and degeneration. Drp1 deficient mitochondria are morphologically bigger and functionally abnormal. The dysfunctional mitochondria signals to the nucleus to induce the ubiquitin-proteasome system and an Unfolded Protein Response while the change of mitochondrial volume results in an increase of mitochondrial Ca2+ uptake and myofiber death. Our findings reveal that morphology of mitochondrial network is critical for several biological processes that control nuclear programs and Ca2+ handling.


Assuntos
Dinaminas/metabolismo , Mitocôndrias Musculares/patologia , Dinâmica Mitocondrial/fisiologia , Miopatias Mitocondriais/patologia , Músculo Esquelético/patologia , Animais , Cálcio/metabolismo , Núcleo Celular/metabolismo , Modelos Animais de Doenças , Dinaminas/genética , Homeostase/fisiologia , Humanos , Camundongos , Camundongos Knockout , Miopatias Mitocondriais/genética , Miopatias Mitocondriais/mortalidade , Músculo Esquelético/citologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Ubiquitinas/metabolismo , Resposta a Proteínas não Dobradas/fisiologia
14.
Dev Genes Evol ; 229(5-6): 147-159, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31214772

RESUMO

Our studies conducted on reptilian limb muscle development revealed, for the first time, early forelimb muscle differentiation at the morphological and molecular level. Sand lizard skeletal muscle differentiation in the early forelimb bud was investigated by light, confocal, and transmission electron microscopy as well as western blot. The early forelimb bud, filled with mesenchymal cells, is surrounded by monolayer epithelium cells. The immunocytochemical analysis revealed the presence of Pax3- and Lbx-positive cells in the vicinity of the ventro-lateral lip (VLL) of the dermomyotome, suggesting that VLL is the source of limb muscle progenitor cells. Furthermore, Pax3- and Lbx-positive cells were observed in the dorsal and ventral myogenic pools of the forelimb bud. Skeletal muscle development in the early limb bud is asynchronous, which is manifested by the presence of myogenic cells in different stages of differentiation: multinucleated myotubes with well-developed contractile apparatus, myoblasts, and mitotically active premyoblasts. The western blot analysis revealed the presence of MyoD and Myf5 proteins in all investigated developmental stages. The MyoD western blot analysis showed two bands corresponding to monomeric (mMyoD) and dimeric (dMyoD) fractions. Two separate bands were also detected in the case of Myf5. The observed bands were related to non-phosphorylated (Myf5) and phosphorylated (pMyf5) fractions of Myf5. Our investigations on sand lizard forelimb myogenesis showed that the pattern of muscle differentiation in the early forelimb bud shares many features with rodents and chicks.


Assuntos
Lagartos/embriologia , Desenvolvimento Muscular , Animais , Feminino , Imunofluorescência , Membro Anterior/embriologia , Botões de Extremidades/citologia , Botões de Extremidades/crescimento & desenvolvimento , Lagartos/genética , Microscopia Confocal , Proteínas Musculares/análise , Proteínas Musculares/genética , Músculo Esquelético/citologia , Músculo Esquelético/embriologia
15.
Cell Biol Int ; 43(7): 799-808, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31050064

RESUMO

Muscle satellite cells are usually at rest, and when externally stimulated or regulated, they can be further differentiated by cell fusion to form new myotubes and muscle fibers. WD repeat domain 13 (WDR13) is highly conserved in vertebrates. Studies have shown that mice lacking the Wdr13 gene develop mild obesity, hyperinsulinemia, and increased islet ß cell proliferation. However, the role of WDR13 in bovine cells is unclear. Here, we investigated the effect of WDR13 on bovine skeletal muscle-derived satellite cells (MDSCs). We found that WDR13 was upregulated in bovine MDSCs using western blotting and immunofluorescence experiments. Moreover, activation and inhibition of WDR13 expression increased and decreased cell differentiation, respectively, suggesting that WDR13 promotes bovine MDSC differentiation. To further understand the mechanism of action of WDR13, we examined changes in the PI3K/AKT signaling pathway following WDR13 activation or inhibition. In addition, cells were treated with a phosphoinositide kinase 3 (PI3K) inhibitor, LY294004, to observe cell differentiation. The results showed that activation of WDR13 inhibited the PI3K/AKT signaling pathway and enhanced cell differentiation. These data suggest that WDR13 can promote the differentiation of bovine MDSCs by affecting the PI3K/AKT signaling pathway.


Assuntos
Diferenciação Celular , Desenvolvimento Muscular , Músculo Esquelético/crescimento & desenvolvimento , Proteínas Nucleares/fisiologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Satélites de Músculo Esquelético/citologia , Animais , Bovinos , Proliferação de Células , Células Cultivadas , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Proteínas Nucleares/genética , Células Satélites de Músculo Esquelético/metabolismo , Transdução de Sinais
16.
PLoS One ; 14(5): e0216392, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31059537

RESUMO

BACKGROUND: Green light penetrates the skull and has directly affected on the secretion of melatonin in plasma, which regulates the endocrine activities to influence the muscle growth, satellite cell mitotic activity and quality properties of meat from the embryonic period to posthatch in chick. Pituitary adenylate cyclase-activating polypeptide 6-38 (PACAP6-38) could inhibit the synthesis and secretion of pineal melatonin. Finding a new way for exploring the mechanism of light-regulated muscle growth in ovo is essential for promoting the productive performance in poultry. METHODS: Chick embryos were exposed to darkness (D-group) and green light (G-group) throughout the embryonic period, and injected with PACAP6-38 or saline at embryonic day 8. Plasma hormone, skeletal muscle fiber areas, satellite cell proliferation activity, paired domain homeobox transcription factor 7 and myogenic regulatory factors were observed. RESULTS: By saline treatment, the percentage of proliferating cell nuclear antigen immunoreactive cells and mitotic activity of satellite cells in skeletal muscle were higher in G-group than those of in D-group at post-hatching day 0. With the increase of plasma melatonin, green light promoted the secretion of growth hormone (GH) and insulin like factor 1 (IGF-1) in plasma, the satellite cell proliferation, the size of muscle fiber, as well as the mRNA expressions of Pax7, myogenic regulatory factors and IGF-1R. After PACAP6-38 treatment to inhibit the secretion of melatonin in ovo, aforementioned parameters were remarkably decreased and the difference of these parameters was disappeared between D-group and G-group. CONCLUSION: These data indicated that stimulation with monochromatic green light during incubation enhanced the secretion of melatonin and up-regulation of GH-IGF-1 axis to activate the satellite cells proliferation and myofiber formation, involving the expression of Pax7 and myogenic regulatory factors.


Assuntos
Proteínas Aviárias/biossíntese , Luz , Desenvolvimento Muscular , Proteínas Musculares/biossíntese , Músculo Esquelético/metabolismo , Células Satélites de Músculo Esquelético/metabolismo , Animais , Embrião de Galinha , Regulação da Expressão Gênica , Músculo Esquelético/citologia , Células Satélites de Músculo Esquelético/citologia
17.
Mol Med Rep ; 19(6): 5087-5096, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059046

RESUMO

The present study aimed to investigate the inhibitory effects and the mechanisms underlying 17ß­estradiol (E2) effects on triglyceride synthesis and insulin resistance in skeletal muscle tissues and cells. Ovariectomy (OVX) was performed on 6­month­old female rats treated with or without E2. Subsequently, various serum biochemical markers were measured. Additionally, pathological alterations of the uterus, liver and skeletal muscle were analyzed, and the content of triglycerides (TG) in muscle was detected. Differentiated myotubes formed by C2C12 cells were treated with palmitic acid (PA) or pretreated with E2, estrogen receptor (ESR) 1 agonist propylpyrazoletriol (PPT) and ESR2 agonist diarylpropionitrile (DPN). Subsequently, the mRNA or protein expression levels of ESR1/2, peroxisome proliferator activated receptor α (PPARα), CD36 molecule (CD36), fatty acid synthase (FASN), perilipin 2 (PLIN2), phosphorylated acetyl­CoA carboxylase α (p­ACACA), p­AKT serine/threonine kinase (p­AKT) and p­mitogen­activated protein kinase 8 (p­MAPK8) were analyzed in skeletal muscle or in C2C12 cells by reverse transcription­semi­quantitative polymerase chain reaction and western blotting. The present results suggested that treatment with E2 inhibited OVX­induced body weight gain, TG accumulation and insulin resistance. The protein or mRNA expression levels of ESR1, CD36, PPARα, p­ACACA and p­AKT were decreased, whereas the protein or mRNA expression levels of ESR2, PLIN2, FASN and p­MAPK8 were increased in the OVX group. Of note, treatment with E2 restored the expression levels of the aforementioned factors. In C2C12 cells, treatment with E2 or PPT reversed the alterations induced by treatment with PA. In contrast, pretreatment with DPN did not influence the effect of PA. Collectively, E2 was able to interact with ESR1, thus activating the CD36­PPARα pathway, decreasing the level of TG in the muscles and improving insulin resistance in skeletal muscles and C2C12 cells.


Assuntos
Estradiol/farmacologia , Receptor alfa de Estrogênio/metabolismo , Triglicerídeos/biossíntese , Animais , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Receptor alfa de Estrogênio/agonistas , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Receptor beta de Estrogênio/metabolismo , Ácido Graxo Sintases/genética , Ácido Graxo Sintases/metabolismo , Feminino , Resistência à Insulina , Camundongos , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Ovariectomia , Ácido Palmítico/farmacologia , Perilipina-2/genética , Perilipina-2/metabolismo , Fenóis/farmacologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirazóis/farmacologia , Ratos , Ratos Sprague-Dawley , Regulação para Cima/efeitos dos fármacos
18.
Mol Cell Biol ; 39(15)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31138662

RESUMO

Skeletal muscle wasting causes both morbidity and mortality of cancer patients. Accumulating evidence suggests that the markers of endoplasmic reticulum (ER) stress and unfolded protein response (UPR) pathways are increased in skeletal muscle under multiple catabolic conditions, including cancer. However, the signaling mechanisms and the role of individual arms of the UPR in the regulation of skeletal muscle mass remain largely unknown. In the present study, we demonstrated that gene expression of Toll-like receptors (TLRs) and myeloid differentiation primary response gene 88 (MyD88) was increased in skeletal muscle in a Lewis lung carcinoma (LLC) model of cancer cachexia. Targeted ablation of MyD88 inhibits the loss of skeletal muscle mass and strength in LLC tumor-bearing mice. Inhibition of MyD88 attenuates the LLC-induced activation of the UPR in skeletal muscle of mice. Moreover, muscle-specific deletion of X-box binding protein 1 (XBP1), a major downstream target of IRE1α arm of the UPR, ameliorates muscle wasting in LLC tumor-bearing mice. Our results also demonstrate that overexpression of an active form of XBP1 caused atrophy in cultured myotubes. In contrast, knockdown of XBP1 inhibits myotube atrophy in response to LLC or C26 adenocarcinoma cell conditioned medium. Collectively, our results demonstrate that TLR/MyD88-mediated activation of XBP1 causes skeletal muscle wasting in LLC tumor-bearing mice.


Assuntos
Caquexia/metabolismo , Carcinoma Pulmonar de Lewis/complicações , Fator 88 de Diferenciação Mieloide/metabolismo , Receptores Toll-Like/metabolismo , Proteína 1 de Ligação a X-Box/metabolismo , Animais , Carcinoma Pulmonar de Lewis/metabolismo , Linhagem Celular Tumoral , Células Cultivadas , Humanos , Camundongos , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Fator 88 de Diferenciação Mieloide/genética , Transdução de Sinais , Resposta a Proteínas não Dobradas , Regulação para Cima , Proteína 1 de Ligação a X-Box/genética
19.
Anim Sci J ; 90(7): 801-807, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31134719

RESUMO

Skeletal muscle consists of bundles of myofibers containing millions of myofibrils, each of which is formed of longitudinally aligned sarcomere structures. Sarcomeres are the minimum contractile unit, which mainly consists of four components: Z-bands, thin filaments, thick filaments, and connectin/titin. The size and shape of the sarcomere component is strictly controlled. Surprisingly, skeletal muscle cells not only synthesize a series of myofibrillar proteins but also regulate the assembly of those proteins into the sarcomere structures. However, authentic sarcomere structures cannot be reconstituted by combining purified myofibrillar proteins in vitro, therefore there must be an elaborate mechanism ensuring the correct formation of myofibril structure in skeletal muscle cells. This review discusses the role of myosin, a main component of the thick filament, in thick filament formation and the dynamics of myosin in skeletal muscle cells. Changes in the number of myofibrils in myofibers can cause muscle hypertrophy or atrophy. Therefore, it is important to understand the fundamental mechanisms by which myofibers control myofibril formation at the molecular level to develop approaches that effectively enhance muscle growth in animals.


Assuntos
Citoesqueleto/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Miosinas/fisiologia , Animais , Atrofia , Hipertrofia , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/patologia , Miofibrilas/metabolismo , Miofibrilas/patologia , Miosinas/metabolismo , Sarcômeros/metabolismo
20.
Nat Commun ; 10(1): 2299, 2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-31127110

RESUMO

Ca2+ coordinates diverse cellular processes, yet how function-specific signals arise is enigmatic. We describe a cell-wide network of distinct cytoplasmic nanocourses with the nucleus at its centre, demarcated by sarcoplasmic reticulum (SR) junctions (≤400 nm across) that restrict Ca2+ diffusion and by nanocourse-specific Ca2+-pumps that facilitate signal segregation. Ryanodine receptor subtype 1 (RyR1) supports relaxation of arterial myocytes by unloading Ca2+ into peripheral nanocourses delimited by plasmalemma-SR junctions, fed by sarco/endoplasmic reticulum Ca2+ ATPase 2b (SERCA2b). Conversely, stimulus-specified increases in Ca2+ flux through RyR2/3 clusters selects for rapid propagation of Ca2+ signals throughout deeper extraperinuclear nanocourses and thus myocyte contraction. Nuclear envelope invaginations incorporating SERCA1 in their outer nuclear membranes demarcate further diverse networks of cytoplasmic nanocourses that receive Ca2+ signals through discrete RyR1 clusters, impacting gene expression through epigenetic marks segregated by their associated invaginations. Critically, this circuit is not hardwired and remodels for different outputs during cell proliferation.


Assuntos
Sinalização do Cálcio/fisiologia , Citosol/metabolismo , Animais , Membrana Celular/metabolismo , Proliferação de Células/fisiologia , Células Cultivadas , Masculino , Células Musculares/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/citologia , Músculo Esquelético/fisiologia , Membrana Nuclear/metabolismo , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
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