Lysophosphatidic acid and bFGF control different modes in proliferating myoblasts.

Yoshida, Shosei; Fujisawa‐Sehara, Atsuko; Taki, Takao; Arai, Ken‐ichi; Nabeshima, Yo‐ichi

doi:10.1083/jcb.132.1.181

Cited by 76 publications

(55 citation statements)

References 77 publications

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“…Conversely, transient transfection of young SCs with either S100B or a dominant negative RAGE mutant resulted in the acquisition of an aged phenotype. We also noted a remarkably reduced ability of aged SCs to secrete bFGF and S100B, which are both potent stimulators of myoblast proliferation (Riuzzi et al 2006b;Yoshida et al 1996), and we found that treatment of aged SCs with either bFGF or S100B or with conditioned medium from young SCs resulted in a nearly complete restoration of the proliferation potential along with an enhanced differentiation when aged SCs were shifted to DM. Thus, it is tempting to speculate that the reduced ability of aged SCs to release bFGF and/or S100B is a one major cause of defective proliferation (i.e., expansion), which is essential for the attainment of the critical cell density necessary for subsequent myotube formation.…”

Section: Discussionsupporting

confidence: 50%

“…As the proliferation rate is strongly affected by mitogenic factors in the medium, some of which are being secreted by myoblasts themselves, we decided to verify if aged SCs maintain the ability to respond to mitogens. To address this point, bFGF or S100B, two factors reported to stimulate myoblast proliferation via activation of ERK1/2 signaling (Riuzzi et al 2006b;Yoshida et al 1996), were added to young and aged SCs cultured in medium containing 2% FBS, and the cells were then tested for BrdU incorporation (Fig. 8a).…”

Section: Young and Aged Scs Show Differential Expression Of Ragementioning

confidence: 99%

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Human muscle satellite cells show age-related differential expression of S100B protein and RAGE

Beccafico

Riuzzi

Puglielli

et al. 2010

AGE

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During aging, skeletal muscles show reduced mass and functional capacity largely due to loss of the regenerative ability of satellite cells (SCs), the quiescent stem cells located beneath the basal lamina surrounding each myofiber. While both the external environment and intrinsic properties of SCs appear to contribute to the age-related SC deficiency, the latter ones have been poorly investigated especially in humans. In the present work, we analyzed several parameters of SCs derived from biopsies of vastus lateralis muscle from healthy non-trained young (28.7±5.9 years; n=10) and aged (77.3±6.4 years; n= 11) people. Compared with young SCs, aged SCs showed impaired differentiation when cultured in differentiation medium, and exhibited the following: (1) reduced proliferation; (2) higher expression levels of S100B, a negative regulator of myoblast differentiation; (3) undetectable levels in growth medium of fulllength RAGE (receptor for advanced glycation end products), a multiligand receptor of the immunoglobulin superfamily, the engagement of which enhances myoblast differentiation; and (4) lower expression levels of the transcription factors, MyoD and Pax7. Also, either overexpression of full-length RAGE or knockdown of S100B in aged SCs resulted in enhanced differentiation, while overexpression of either a nontransducing mutant of RAGE (RAGEΔcyto) or S100B in young SCs resulted in reduced differentiation compared with controls. Moreover, while aged SCs maintained the ability to respond to mitogenic factors (e.g., bFGF and S100B), they were no longer able to secrete these factors, unlike young SCs. These data support a role for intrinsic factors, besides the extracellular environment in the defective SC function in aged skeletal muscles.

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Section: Discussionsupporting

confidence: 50%

Section: Young and Aged Scs Show Differential Expression Of Ragementioning

confidence: 99%

Human muscle satellite cells show age-related differential expression of S100B protein and RAGE

Beccafico

Riuzzi

Puglielli

et al. 2010

AGE

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“…Though highmitogen growth medium inhibits myogenesis, a low rate of differentiation can be detected in highly confluent cultures of C2C12 cells (6,58). Induction of Akt was also detected under these conditions, but it occurred more slowly than in differentiation medium (compare Fig.…”

Section: Resultsmentioning

confidence: 88%

Cell Cycle Withdrawal Promotes Myogenic Induction of Akt, a Positive Modulator of Myocyte Survival

Fujio

Guo

Mano

et al. 1999

Molecular and Cellular Biology

203

198

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During myogenesis, proliferating myoblasts withdraw from the cell cycle, acquire an apoptosis-resistant phenotype, and differentiate into myotubes. Previous studies indicate that myogenic induction of the cyclindependent kinase inhibitor p21 results in an inhibition of apoptotic cell death in addition to its role as a negative cell cycle regulator. Here we demonstrate that the protein encoded by the Akt proto-oncogene is induced in C2C12 cells during myogenic differentiation with a corresponding increase in kinase activity. In differentiating cultures, expression of dominant-negative forms of Akt increase the frequency of cell death whereas expression of wild-type Akt protects against death, indicating that Akt is a positive modulator of myocyte survival. Antisense oligonucleotides against p21 block cell cycle withdrawal, inhibit Akt induction, and enhance cell death in differentiating myocyte cultures. Adenovirus-mediated transfer of wild-type or constitutively active Akt constructs confer partial resistance to cell death under conditions where cell cycle exit is blocked by the antisense oligonucleotides. Collectively, these data indicate that cell cycle withdrawal facilitates the induction of Akt during myogenesis, promoting myocyte survival.During myogenesis, proliferating myoblasts irreversibly withdraw from the cell cycle and differentiate into myotubes. The cyclin-dependent kinase (CDK) inhibitor p21 and the retinoblastoma protein (pRb) appear to be critical in establishing the postmitotic state during myogenesis (55). p21 is markedly induced in differentiating C2C12 cells and in 10T1/2 fibroblasts that are induced to differentiate following transformation with MyoD (23,24,40,42). Bromodeoxyuridine-labeling experiments have shown that upregulation of p21 correlates with the initiation of cell cycle exit, an early event in the myogenic differentiation pathway (4). Myocytes lacking pRb, a downstream target of CDK inhibitors, are incapable of irreversible cell cycle exit upon differentiation (41,46). The transcription of muscle-specific genes can be inhibited by the forced expression of cyclins and CDKs, or E2F1, and this inhibition is largely reversed by the expression of constitutively active mutants of pRb (22). It is reported that the myocyte differentiation and cell cycle-regulatory functions of pRb and E2F1 require different domains within these proteins (22,48).

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“…Stimulation of PC12 cells with FGF-2 induces differentiation via sustained activation of the Erks, which is mediated by recruitment of SHP-2 to FRS-2␣ (17). In contrast, the FGFR signaling pathway engaged by myoblasts suppresses myogenesis (8,29,57,63,73). It remains to be established whether SHP-2 participates downstream of the FGFR in myoblasts to mediate entry into myogenesis.…”

mentioning

confidence: 99%

Role of SHP-2 in Fibroblast Growth Factor Receptor-Mediated Suppression of Myogenesis in C2C12 Myoblasts

Kontaridis

Liu

Zhang

et al. 2002

Molecular and Cellular Biology

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Ligand activation of the fibroblast growth factor receptor (FGFR) represses myogenesis and promotes activation of extracellular signal-regulated kinases 1 and 2 (Erks). The precise mechanism through which the FGFR transmits both of these signals in myoblasts remains unclear. The SH2 domain-containing protein tyrosine phosphatase, SHP-2, has been shown to participate in the regulation of FGFR signaling. However, no role for SHP-2 in FGFR myogenic signaling is known. In this study, we show that stimulation of C2C12 myoblasts with FGF-2 induces SHP-2 complex formation with tyrosyl-phosphorylated FGFR substrate 2␣ (FRS-2␣). Both the catalytic activity and, to a much lesser extent, the Grb2 binding-tyrosyl phosphorylation sites of SHP-2 are required for maximal FGF-2-induced Erk activity and Elk-1 transactivation. When overexpressed in C2C12 myoblasts, wild-type SHP-2, but not a catalytically inactive SHP-2 mutant, potentiates the suppressive effects of FGF-2 on muscle-specific gene expression. In addition, expression of a constitutively active mutant of SHP-2 is sufficient to prevent myogenesis. The constitutively active mutant of SHP-2 induces hyper-tyrosyl phosphorylation of FRS-2␣ but fails to stimulate or potentiate either FGF-2-induced Erk activation or Elk-1 transactivation. These data suggest that in myoblasts, SHP-2 represses myogenesis via a pathway that is independent of the Erks. We propose that SHP-2 plays a pivotal role in FGFR signaling in myoblasts via both Erk-dependent and Erk-independent pathways.Cell lines of the myogenic lineage provide an excellent model for studying signaling pathways that control the decision between growth and differentiation. In culture, myogenic cell lines are inhibited in their ability to differentiate when exposed to serum, fibroblast growth factors (FGFs), and transforming growth factor ␤ (8, 29,57,63,73). It is now believed that mitogens prevent myogenesis by maintaining myoblasts in the proliferative phase, thereby suppressing muscle-specific gene expression and terminal differentiation (28,38,56). Upon mitogen withdrawal, cultured myoblasts exit the cell cycle and coordinately activate muscle regulatory factors (MRFs) in the basic helix-loop-helix (bHLH) family. These MRFs, such as MyoD, myogenin, Myf5, and MRF4, promote skeletal muscle differentiation by activating muscle-specific genes that include the myosin light and heavy chains, desmin, and troponin T (11,43,67).The intracellular signaling cascades that regulate entry into myogenesis have been the focus of several laboratories. Some of these studies suggest that extracellular signal-regulated kinases 1 and 2 (Erks) negatively regulate the initiation of myogenesis. A combination of pharmacological inhibitors, overexpression of dominant-interfering mutants of the Erk pathway, and overexpression of the mitogen-activated protein kinase (MAPK) phosphatase 1 all demonstrate that the Erks negatively regulate myogenesis (5, 9, 69, 70). One report indicates that the Erks positively regulate myogenesis (16), while others ...

show abstract

Lysophosphatidic acid and bFGF control different modes in proliferating myoblasts.

Cited by 76 publications

References 77 publications

Human muscle satellite cells show age-related differential expression of S100B protein and RAGE

Human muscle satellite cells show age-related differential expression of S100B protein and RAGE

Cell Cycle Withdrawal Promotes Myogenic Induction of Akt, a Positive Modulator of Myocyte Survival

Role of SHP-2 in Fibroblast Growth Factor Receptor-Mediated Suppression of Myogenesis in C2C12 Myoblasts

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