Cellular and Molecular Mechanisms of Muscle Cell Differentiation in Ascidian Embryos

Utilizing a muscle-specific monoclonal antibody (Mu-2) as a probe, we analysed developmental mechanisms involved in muscle cell differentiation in ascidian embryos. The antigen recognized by Mu-2 was a single polypeptide with a relative molecular mass of about 220 X 10(3). It first appeared at the early tailbud stage and continued to be expressed until the swimming larva stage. There were distinct and separate puromycin and actinomycin D sensitivity periods during the occurrence of the antigen, suggesting the new synthesis of the polypeptide by developing muscle cells. Embryos that had been permanently arrested with aphidicolin in the early cleavage stages up to the 32-cell stage did not express the antigen. DNA replications may be required for the antigen expression. Embryos that had been arrested with cytochalasin B in the 8-cell and later stages developed the antigen, and the number and position of the arrested blastomeres exhibiting the differentiation marker almost corresponded to those of the B4.1-line muscle lineage. Furthermore, in quarter embryos developed from each blastomere pair isolated from the 8-cell embryo, all the B4.1 as well as a part of b4.2 partial embryos expressed the antigen, while the a4.2 and A4.1 partial embryos did not show the antigen expression. These results may provide further support for the existence of cytoplasmic determinants for muscle cell differentiation in this mosaic egg.

Download Full-text

FoxO1a-Cyclic GMP-Dependent Kinase I Interactions Orchestrate Myoblast Fusion

Molecular and Cellular Biology ◽

10.1128/mcb.25.17.7645-7656.2005 ◽

2005 ◽

Vol 25 (17) ◽

pp. 7645-7656 ◽

Cited By ~ 25

Author(s):

Philippe R. J. Bois ◽

Vanessa F. Brochard ◽

Adèle V. A. Salin-Cantegrel ◽

John L. Cleveland ◽

Gerard C. Grosveld

Keyword(s):

Cell Differentiation ◽

Muscle Cell ◽

Cyclic Gmp ◽

Molecular Mechanisms ◽

Binding Activity ◽

Myoblast Fusion ◽

Muscle Cell Differentiation ◽

Dna Binding Activity ◽

Regulatory Circuits ◽

Myoblast Cell

ABSTRACT The regulatory circuits that orchestrate mammalian myoblast cell fusion during myogenesis are poorly understood. The transcriptional activity of FoxO1a directly regulates this process, yet the molecular mechanisms governing FoxO1a activity during muscle cell differentiation remain unknown. Here we show an autoregulatory loop in which FoxO1a directly activates transcription of the cyclic GMP-dependent protein kinase I (cGKI) gene and where the ensuing cGKI activity phosphorylates FoxO1a and abolishes its DNA binding activity. These findings establish the FoxO1a-to-cGKI pathway as a novel feedback loop that allows the precise tuning of myoblast fusion. Interestingly, this pathway appears to operate independently of muscle cell differentiation programs directed by myogenic transcription factors.

Download Full-text

Effect of Ashwagandha Withanolides on Muscle Cell Differentiation

Biomolecules ◽

10.3390/biom11101454 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1454

Author(s):

Jia Wang ◽

Huayue Zhang ◽

Ashish Kaul ◽

Kejuan Li ◽

Didik Priyandoko ◽

...

Keyword(s):

Cell Differentiation ◽

Muscle Cell ◽

Withania Somnifera ◽

Molecular Mechanisms ◽

Disease Model ◽

Neuromuscular Disorder ◽

Withaferin A ◽

C2c12 Myoblasts ◽

Muscle Cell Differentiation ◽

Health Promoting

Withania somnifera (Ashwagandha) is used in Indian traditional medicine, Ayurveda, and is believed to have a variety of health-promoting effects. The molecular mechanisms and pathways underlying these effects have not yet been sufficiently explored. In this study, we investigated the effect of Ashwagandha extracts and their major withanolides (withaferin A and withanone) on muscle cell differentiation using C2C12 myoblasts. We found that withaferin A and withanone and Ashwagandha extracts possessing different ratios of these active ingredients have different effects on the differentiation of C2C12. Withanone and withanone-rich extracts caused stronger differentiation of myoblasts to myotubes, deaggregation of heat- and metal-stress-induced aggregated proteins, and activation of hypoxia and autophagy pathways. Of note, the Parkinson’s disease model of Drosophila that possess a neuromuscular disorder showed improvement in their flight and climbing activity, suggesting the potential of Ashwagandha withanolides for the management of muscle repair and activity.

Download Full-text