scholarly journals pRb-Dependent Cyclin D3 Protein Stabilization Is Required for Myogenic Differentiation

2007 ◽  
Vol 27 (20) ◽  
pp. 7248-7265 ◽  
Author(s):  
Francesca De Santa ◽  
Sonia Albini ◽  
Eleonora Mezzaroma ◽  
Livio Baron ◽  
Armando Felsani ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Myogenic Differentiation ◽  
Ectopic Expression ◽  
Protein Stabilization ◽  
Cyclin D3 ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Protein Accumulation ◽  
C Terminus ◽  
Gsk 3Β

ABSTRACT The expression of retinoblastoma (pRb) and cyclin D3 proteins is highly induced during the process of skeletal myoblast differentiation. We have previously shown that cyclin D3 is nearly totally associated with hypophosphorylated pRb in differentiated myotubes, whereas Rb − / − myocytes fail to accumulate the cyclin D3 protein despite normal induction of cyclin D3 mRNA. Here we report that pRb promotes cyclin D3 protein accumulation in differentiating myoblasts by preventing cyclin D3 degradation. We show that cyclin D3 displays rapid turnover in proliferating myoblasts, which is positively regulated through glycogen synthase kinase 3β (GSK-3β)-mediated phosphorylation of cyclin D3 on Thr-283. We describe a novel interaction between pRb and cyclin D3 that maps to the C terminus of pRb and to a region of cyclin D3 proximal to the Thr-283 residue and provide evidence that the pRb-cyclin D3 complex formation in terminally differentiated myotubes hinders the access of GSK-3β to cyclin D3, thus inhibiting Thr-283 phosphorylation. Interestingly, we observed that the ectopic expression of a stabilized cyclin D3 mutant in C2 myoblasts enhances muscle-specific gene expression; conversely, cyclin D3-null embryonic fibroblasts display impaired MyoD-induced myogenic differentiation. These results indicate that the pRb-dependent accumulation of cyclin D3 is functionally relevant to the process of skeletal muscle cell differentiation.

scholarly journals The oncogenic forms of N-ras or H-ras prevent skeletal myoblast differentiation.

1987 ◽  
Vol 7 (6) ◽  
pp. 2104-2111 ◽  
Author(s):  
E N Olson ◽  
G Spizz ◽  
M A Tainsky
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Transforming Growth Factor ◽  
Myogenic Differentiation ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Gene Products ◽  
Fibroblast Growth ◽  
Ras Genes

Differentiation of skeletal muscle involves withdrawal of myoblasts from the cell cycle, fusion to form myotubes, and the coordinate expression of a variety of muscle-specific gene products. Fibroblast growth factor and type beta transforming growth factor specifically inhibit myogenesis; however, the transmembrane signaling pathways responsible for suppression of differentiation by these growth factors remain elusive. Because ras proteins have been implicated in the transduction of growth factor signals across the plasma membrane, we used DNA-mediated gene transfer to investigate the potential involvement of this family of regulatory proteins in the control of myogenesis. Transfection of the mouse skeletal muscle cell line C2 with the oncogenic forms of H-ras or N-ras completely suppressed both myoblast fusion and induction of the muscle-specific gene products nicotinic acetylcholine receptor and creatine kinase. Inhibition of differentiation by activated ras genes occurred at the level of muscle-specific mRNA accumulation. In contrast, proto-oncogenic forms of N-ras or H-ras had no apparent effects on the ability of C2 cells to differentiate. Myoblasts transfected with activated ras genes exhibited normal growth properties and ceased proliferating in the absence of mitogens, indicating that ras inhibited differentiation through a mechanism independent of cell proliferation. These results demonstrate that activated ras gene products mimic the inhibitory effects of fibroblast growth factor and type beta transforming growth factor on myogenic differentiation and suggest that each of these regulators of myogenesis may operate through a common intracellular pathway.

scholarly journals A Switch in Akt Isoforms Is Required for Notch-Induced Snail1 Expression and Protection from Cell Death

2015 ◽  
Vol 36 (6) ◽  
pp. 923-940 ◽  
Author(s):  
Alex Frías ◽  
Guillem Lambies ◽  
Rosa Viñas-Castells ◽  
Catalina Martínez-Guillamon ◽  
Natàlia Dave ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Glycogen Synthase ◽  
Total Activity ◽  
Transforming Growth Factor Β1 ◽  
Protein Stabilization ◽  
Nuclear Retention ◽  
Mesenchymal Transition ◽  
Akt Isoforms ◽  
Gsk 3Β ◽  
Transcriptional Complex

Notch activation in aortic endothelial cells (ECs) takes place at embryonic stages during cardiac valve formation and induces endothelial-to-mesenchymal transition (EndMT). Using aortic ECs, we show here that active Notch expression promotes EndMT, resulting in downregulation of vascular endothelial cadherin (VE-cadherin) and upregulation of mesenchymal genes such as those for fibronectin and Snail1/2. In these cells, transforming growth factor β1 exacerbates Notch effects by increasing Snail1 and fibronectin activation. When Notch-downstream pathways were analyzed, we detected an increase in glycogen synthase kinase 3β (GSK-3β) phosphorylation and inactivation that facilitates Snail1 nuclear retention and protein stabilization. However, the total activity of Akt was downregulated. The discrepancy between Akt activity and GSK-3β phosphorylation is explained by a Notch-induced switch in the Akt isoforms, whereby Akt1, the predominant isoform expressed in ECs, is decreased and Akt2 transcription is upregulated. Mechanistically, Akt2 induction requires the stimulation of the β-catenin/TCF4 transcriptional complex, which activates theAkt2promoter. Active, phosphorylated Akt2 translocates to the nucleus in Notch-expressing cells, resulting in GSK-3β inactivation in this compartment. Akt2, but not Akt1, colocalizes in the nucleus with lamin B in the nuclear envelope. In addition to promoting GSK-3β inactivation, Notch downregulates Forkhead box O1 (FoxO1), another Akt2 nuclear substrate. Moreover, Notch protects ECs from oxidative stress-induced apoptosis through an Akt2- and Snail1-dependent mechanism.

MicroRNA-139-5p regulates C2C12 cell myogenesis through blocking Wnt/β-catenin signaling pathway

2015 ◽  
Vol 93 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Lin Mi ◽  
Youlei Li ◽  
Qiangling Zhang ◽  
Chen Zhao ◽  
Ying Peng ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Glycogen Synthase ◽  
C2c12 Cell ◽  
Negative Regulator ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
C2c12 Myoblast ◽  
Myoblast Proliferation ◽  
Gsk 3Β

MicroRNAs (miRNAs) are novel and potent regulators in myogenesis. However, the molecular mechanisms that many miRNAs regulate myoblast proliferation and differentiation which are largely unknown. Here, we found that miR-139-5p increased during C2C12 myoblast proliferation, while presenting an inverse trend during C2C12 myoblast differentiation. Flow cytometry and EdU incorporation assay showed that miR-139-5p slowed down the growth of C2C12 cells. Additional study demonstrated that ectopic introduction of miR-139-5p into C2C12 cells blocked myoblast differentiation. Importantly, we demonstrated for the first time that Wnt1, which is associated with the Wnt/β-catenin signaling pathway, was a direct target of miR-139-5p. Moreover, we found that the expression level of Wnt1 was suppressed significantly (p < 0.01) by miR-139-5p, which triggered inhibition of Wnt/β-catenin signaling through upregulation of glycogen synthase kinase 3 beta (GSK-3β; p < 0.05) and downregulation of p-GSK-3β (p < 0.01), β-catenin (p < 0.05), and nuclear β-catenin (p < 0.01). Taken together, these results suggest that miR-139-5p is an important negative regulator in myogenesis through blocking the Wnt1-mediated Wnt/β-catenin signaling pathway.

Myogenic differentiation during regrowth of atrophied skeletal muscle is associated with inactivation of GSK-3β

2007 ◽  
Vol 292 (5) ◽  
pp. C1636-C1644 ◽  
Author(s):  
Jos L. J. van der Velden ◽  
Ramon C. J. Langen ◽  
Marco C. J. M. Kelders ◽  
Jodil Willems ◽  
Emiel F. M. Wouters ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Glycogen Synthase ◽  
Myogenic Differentiation ◽  
Hindlimb Suspension ◽  
Akt Phosphorylation ◽  
Proliferation And Differentiation ◽  
Igf I ◽  
Myoblast Proliferation ◽  
Gsk 3Β ◽  
First Time

Muscle atrophy contributes to morbidity and mortality in aging and chronic disease, emphasizing the need to gain understanding of the mechanisms involved in muscle atrophy and (re)growth. We hypothesized that the magnitude of muscle regrowth during recovery from atrophy determines whether myonuclear accretion and myogenic differentiation are required and that insulin-like growth factor (IGF)-I/Akt/glycogen synthase kinase (GSK)-3β signaling differs between regrowth responses. To address this hypothesis we subjected mice to hindlimb suspension (HS) to induce atrophy of soleus (−40%) and plantaris (−27%) muscle. Reloading-induced muscle regrowth was complete after 14 days and involved an increase in IGF-IEa mRNA expression that coincided with Akt phosphorylation in both muscles. In contrast, phosphorylation and inactivation of GSK-3β were observed during soleus regrowth only. Furthermore, soleus but not plantaris regrowth involved muscle regeneration based on a transient increase in expression of histone 3.2 and myosin heavy chain-perinatal, which are markers of myoblast proliferation and differentiation, and a strong induction of muscle regulatory factor (MRF) expression. Experiments in cultured muscle cells showed that IGF-I-induced MRF expression is facilitated by inactivation of GSK-3β and selectively occurs in the myoblast population. This study suggests that induction of IGF-I expression and Akt phosphorylation during recovery from muscle atrophy is independent of the magnitude of muscle regrowth. Moreover, our data demonstrate for the first time that the regenerative response characterized by myoblast proliferation, differentiation, and increased MRF expression in recovering muscle is associated with the magnitude of regrowth and may be regulated by inactivation of GSK-3β.

The oncogenic forms of N-ras or H-ras prevent skeletal myoblast differentiation

1987 ◽  
Vol 7 (6) ◽  
pp. 2104-2111
Author(s):  
E N Olson ◽  
G Spizz ◽  
M A Tainsky
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Transforming Growth Factor ◽  
Myogenic Differentiation ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Gene Products ◽  
Fibroblast Growth ◽  
Ras Genes

Differentiation of skeletal muscle involves withdrawal of myoblasts from the cell cycle, fusion to form myotubes, and the coordinate expression of a variety of muscle-specific gene products. Fibroblast growth factor and type beta transforming growth factor specifically inhibit myogenesis; however, the transmembrane signaling pathways responsible for suppression of differentiation by these growth factors remain elusive. Because ras proteins have been implicated in the transduction of growth factor signals across the plasma membrane, we used DNA-mediated gene transfer to investigate the potential involvement of this family of regulatory proteins in the control of myogenesis. Transfection of the mouse skeletal muscle cell line C2 with the oncogenic forms of H-ras or N-ras completely suppressed both myoblast fusion and induction of the muscle-specific gene products nicotinic acetylcholine receptor and creatine kinase. Inhibition of differentiation by activated ras genes occurred at the level of muscle-specific mRNA accumulation. In contrast, proto-oncogenic forms of N-ras or H-ras had no apparent effects on the ability of C2 cells to differentiate. Myoblasts transfected with activated ras genes exhibited normal growth properties and ceased proliferating in the absence of mitogens, indicating that ras inhibited differentiation through a mechanism independent of cell proliferation. These results demonstrate that activated ras gene products mimic the inhibitory effects of fibroblast growth factor and type beta transforming growth factor on myogenic differentiation and suggest that each of these regulators of myogenesis may operate through a common intracellular pathway.

scholarly journals Critical Role Played by Cyclin D3 in the MyoD-Mediated Arrest of Cell Cycle during Myoblast Differentiation

1999 ◽  
Vol 19 (7) ◽  
pp. 5203-5217 ◽  
Author(s):  
Carlo Cenciarelli ◽  
Francesca De Santa ◽  
Pier Lorenzo Puri ◽  
Elisabetta Mattei ◽  
Letizia Ricci ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Critical Role ◽  
Cyclin D3 ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Gene Expressions ◽  
Adenovirus E1a ◽  
Skeletal Myoblasts ◽  
Myogenic Factors ◽  
Cell Cycle Inhibitors

ABSTRACT During the terminal differentiation of skeletal myoblasts, the activities of myogenic factors regulate not only tissue-specific gene expressions but also the exit from the cell cycle. The induction of cell cycle inhibitors such as p21 and pRb has been shown to play a prominent role in the growth arrest of differentiating myoblasts. Here we report that, at the onset of differentiation, activation by MyoD of the Rb, p21, and cyclin D3 genes occurs in the absence of new protein synthesis and with the requirement of the p300 transcriptional coactivator. In differentiated myocytes, cyclin D3 also becomes stabilized and is found nearly totally complexed with unphosphorylated pRb. The detection of complexes containing cyclin D3, cdk4, p21, and PCNA suggests that cdk4, along with PCNA, may get sequestered into high-order structures held together by pRb and cyclin D3. Cyclin D3 up-regulation and stabilization is inhibited by adenovirus E1A, and this correlates with the ability of E1A to promote pRb phosphorylation; conversely, the overexpression of cyclin D3 in differentiated myotubes counteracts the E1A-mediated reactivation of DNA synthesis. These results indicate that cyclin D3 critically contributes to the irreversible exit of differentiating myoblasts from the cell cycle.

scholarly journals Overlapping Functions of Nuclear Envelope Proteins NET25 (Lem2) and Emerin in Regulation of Extracellular Signal-Regulated Kinase Signaling in Myoblast Differentiation

2009 ◽  
Vol 29 (21) ◽  
pp. 5718-5728 ◽  
Author(s):  
Michael D. Huber ◽  
Tinglu Guan ◽  
Larry Gerace
Keyword(s):  
Nuclear Envelope ◽  
Transforming Growth Factor ◽  
Myogenic Differentiation ◽  
Ectopic Expression ◽  
Transforming Growth Factor Β ◽  
Mitogen Activated Protein Kinase ◽  
Myoblast Differentiation ◽  
Extracellular Signal Regulated Kinase ◽  
Pharmacological Inhibition ◽  
Extracellular Signal

ABSTRACT Mutations in certain nuclear envelope (NE) proteins cause muscular dystrophies and other disorders, but the disease mechanisms remain unclear. The nuclear envelope transmembrane protein NET25 (Lem2) is a truncated paralog of MAN1, an NE component linked to bone disorders. NET25 and MAN1 share an ∼40-residue LEM homology domain with emerin, the protein mutated in X-linked Emery-Dreifuss muscular dystrophy. However, roles for NET25 and MAN1 in myogenesis have not yet been described. Using RNA interference in C2C12 myoblasts, we show for the first time that both NET25 and MAN1 are required for myogenic differentiation. NET25 depletion causes hyperactivation of extracellular signal-regulated kinase 1/2 at the onset of differentiation, and pharmacological inhibition of this transient overactivation rescues myogenesis. In contrast, pharmacological inhibition of both mitogen-activated protein kinase and transforming growth factor β signaling is required to rescue differentiation after MAN1 depletion. Ectopic expression of silencing-resistant NET25 rescues myogenesis after depletion of emerin but not after MAN1 silencing. Thus, NET25 and emerin have at least partially overlapping functions during myogenic differentiation, which are distinct from those of MAN1. Our work supports the hypothesis that deregulation of cell signaling contributes to NE-linked disorders and suggests that mutations in NET25 and MAN1 may cause muscle diseases.

scholarly journals NCAPG Dynamically Coordinates the Myogenesis of Fetal Bovine Tissue by Adjusting Chromatin Accessibility

2020 ◽  
Vol 21 (4) ◽  
pp. 1248
Author(s):  
Xin Hu ◽  
Yishen Xing ◽  
Xing Fu ◽  
Qiyuan Yang ◽  
Ling Ren ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Throughput Sequencing ◽  
Myogenic Differentiation ◽  
Chromatin Condensation ◽  
Chromatin Accessibility ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Specific Gene Expression ◽  
Bovine Tissue ◽  
Fetal Bovine

NCAPG is a subunit of condensin I that plays a crucial role in chromatin condensation during mitosis. NCAPG has been demonstrated to be associated with farm animal growth traits. However, its role in regulating myoblast differentiation is still unclear. We used myoblasts derived from fetal bovine tissue as an in vitro model and found that NCAPG was expressed during myogenic differentiation in the cytoplasm and nucleus. Silencing NCAPG prolonged the mitosis and impaired the differentiation due to increased myoblast apoptosis. After 1.5 days of differentiation, silencing NCAPG enhanced muscle-specific gene expression. An assay for transposase-accessible chromatin- high throughput sequencing (ATAC-seq) revealed that silencing NCAPG altered chromatin accessibility to activating protein 1 (AP-1) and its subunits. Knocking down the expression of the AP-1 subunits fos-related antigen 2 (FOSL2) or junB proto-oncogene (JUNB) enhanced part of the muscle-specific gene expression. In conclusion, our data provide valuable evidence about NCAPG’s function in myogenesis, as well as its potential role in gene expression.

scholarly journals Chromatin reorganization during myoblast differentiation involves the caspase-dependent removal of SATB2

2019 ◽  
Author(s):  
Ryan A.V. Bell ◽  
Mohammad H. Al-Khalaf ◽  
Steve Brunette ◽  
Alphonse Chu ◽  
Georg Dechant ◽  
...  
Keyword(s):  
Myogenic Differentiation ◽  
Myoblast Differentiation ◽  
Specific Gene ◽  
Genome Reorganization ◽  
Genome Wide ◽  
Caspase 7 ◽  
Culture Models ◽  
Cell Culture Models ◽  
Lineage Specific Gene

SummaryInduction of lineage-specific gene programs are strongly influenced by alterations in local chromatin architecture. However, key players that impact this genome reorganization remain largely unknown. Here, we report that removal of special AT-rich binding protein 2 (SATB2), a nuclear protein that binds matrix attachment regions, is a key event in initiating myogenic differentiation. Deletion of SATB2 in muscle cell culture models and in vivo, accelerates differentiation and depletes the muscle progenitor pool, respectively. Genome wide analysis indicates that SATB2 binding is both repressive and inductive, as loss of SATB2 leads to expression of differentiation regulatory factors and inhibition of genes that impair this process. Finally, we noted that the differentiation-specific decline in SATB2 protein is dependent on a caspase 7-mediated cleavage event. Taken together, this study demonstrates that temporal control of SATB2 protein is critical for shaping the chromatin environment and coordinating the myogenic differentiation program.Graphical Abstract

Synthesis of Coumarin Derivatives as Versatile Scaffolds for GSK-3β Enzyme Inhibition

2020 ◽  
Vol 20 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Carla S. Francisco ◽  
Clara L. Javarini ◽  
Iatahanderson de S. Barcelos ◽  
Pedro A.B. Morais ◽  
Heberth de Paula ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Glycogen Synthase ◽  
Synthetic Methods ◽  
Kinase Assay ◽  
Crystallographic Structure ◽  
Coumarin Derivatives ◽  
Enzymatic Production ◽  
Docking Simulations ◽  
In Silico Studies ◽  
Gsk 3Β

Background: Glycogen synthase kinase-3 (GSK-3) is involved in the phosphorylation and inactivation of glycogen synthase. GSK-3 inhibitors have been associated with a variety of diseases, including Alzheimer´s disease (AD), diabetes type II, neurologic disorders, and cancer. The inhibition of GSK-3β isoforms is likely to represent an effective strategy against AD. Objective: The present work aimed to design and synthesize coumarin derivatives to explore their potential as GSK-3β kinase inhibitors. Method: The through different synthetic methods were used to prepare coumarin derivatives. The GSK-3β activity was measured through the ADP-Glo™ Kinase Assay, which quantifies the kinasedependent enzymatic production of ADP from ATP, using a coupled-luminescence-based reaction. A docking study was performed by using the crystallographic structure of the staurosporine/GSK-3β complex [Protein Data Bank (PDB) code: 1Q3D]. Results: The eleven coumarin derivatives were obtained and evaluated as potential GSK-3β inhibitors. Additionally, in silico studies were performed. The results revealed that the compounds 5c, 5d, and 6b inhibited GSK-3β enzymatic activity by 38.97–49.62% at 1 mM. The other coumarin derivatives were tested at 1 mM, 1 µM, and 1 nM concentrations and were shown to be inhibitor candidates, with significant IC50 (1.224–6.875 µM) values, except for compound 7c (IC50 = 10.809 µM). Docking simulations showed polar interactions between compound 5b and Lys85 and Ser203, clarifying the mechanism of the most potent activity. Conclusion: The coumarin derivatives 3a and 5b, developed in this study, showed remarkable activity as GSK-3β inhibitors.

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