scholarly journals Role of Transmembrane 4 Superfamily (Tm4sf) Proteins Cd9 and Cd81 in Muscle Cell Fusion and Myotube Maintenance

1999 ◽  
Vol 146 (4) ◽  
pp. 893-904 ◽  
Author(s):  
Isao Tachibana ◽  
Martin E. Hemler
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Fusion ◽  
Muscle Cell ◽  
C2c12 Cell ◽  
Ectopic Expression ◽  
C2c12 Cells ◽  
C2c12 Myoblast ◽  
Syncytia Formation ◽  
Transmembrane 4 Superfamily

The role of transmembrane 4 superfamily (TM4SF) proteins during muscle cell fusion has not been investigated previously. Here we show that the appearance of TM4SF protein, CD9, and the formation of CD9–β1 integrin complexes were both regulated in coordination with murine C2C12 myoblast cell differentiation. Also, anti-CD9 and anti-CD81 monoclonal antibodies substantially inhibited and delayed conversion of C2C12 cells to elongated myotubes, without affecting muscle-specific protein expression. Studies of the human myoblast-derived RD sarcoma cell line further demonstrated that TM4SF proteins have a role during muscle cell fusion. Ectopic expression of CD9 caused a four- to eightfold increase in RD cell syncytia formation, whereas anti-CD9 and anti-CD81 antibodies markedly delayed RD syncytia formation. Finally, anti-CD9 and anti-CD81 monoclonal antibodies triggered apoptotic degeneration of C2C12 cell myotubes after they were formed. In summary, TM4SF proteins such as CD9 and CD81 appear to promote muscle cell fusion and support myotube maintenance.

PGC-1α is associated with C2C12 Myoblast differentiation

2014 ◽  
Vol 9 (11) ◽  
pp. 1030-1036 ◽  
Author(s):  
Yaqiu Lin ◽  
Yanying Zhao ◽  
Ruiwen Li ◽  
Jiaqi Gong ◽  
Yucai Zheng ◽  
...  
Keyword(s):  
Mrna Level ◽  
Biological Significance ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
C2c12 Myoblast ◽  
Mrna Levels ◽  
Transfected Cells ◽  
Myosin Heavy Chain Isoform ◽  
Important Mediator

AbstractPGC-1α has been implicated as an important mediator of functional capacity of skeletal muscle. However, the role of PGC-1α in myoblast differentiation remains unexplored. In the present study, we observed a significant up-regulation of PGC-1α expression during the differentiation of murine C2C12 myoblast. To understand the biological significance of PGC-1α up-regulation in myoblast differentiation, C2C12 cells were transfected with murine PGC-1α cDNA and siRNA targeting PGC-1α, respectively. PGC-1α over-expressing clones fused to form typical myotubes with higher mRNA level of myosin heavy chain isoform I (MyHCI) and lower MyHCIIX. No obvious differentiation was observed in PGC-1α-targeted siRNA-transfected cells with marked decrement of mRNA levels of MyHCI and MyHCIIX. Furthermore, PGC-1α increased the expression of MyoD and MyoG in C2C12 cells, which controlled the commitment of precursor cells to myotubes. These results indicate that PGC-1α is associated with myoblast differentiation and elevates MyoD and MyoG expression levels in C2C12 cells.

scholarly journals Fer1L5, a Dysferlin Homologue Present in Vesicles and Involved in C2C12 Myoblast Fusion and Membrane Repair

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 386
Author(s):  
R. Usha Kalyani ◽  
K. Perinbam ◽  
P. Jeyanthi ◽  
Naif Abdullah Al-Dhabi ◽  
Mariadhas Valan Arasu ◽  
...  
Keyword(s):  
Myoblast Fusion ◽  
C2c12 Cells ◽  
Muscle Membrane ◽  
C2c12 Myoblast ◽  
Related Protein ◽  
Membrane Repair ◽  
Ionic Detergent ◽  
Biochemical Fractionation ◽  
Two Stages

Fer1L5 is a dysferlin and myoferlin related protein, which has been predicted to have a role in vesicle trafficking and muscle membrane fusion events. Mutations in dysferlin and otoferlin genes cause heredity diseases: muscular dystrophy and deafness in humans, respectively. Dysferlin is implicated in membrane repair. Myoferlin has a role in myogenesis. In this study, we investigated the role of the Fer1L5 protein during myoblast fusion and membrane repair. To study the functions of Fer1L5 we used confocal microscopy, biochemical fractionation, Western blot analysis and multiphoton laser wounding assay. By immunolabelling, Fer1L5 was detected in vesicular structures. By biochemical fractionation Fer1L5 was observed in low density vesicles. Our studies show that the membranes of Fer1L5 vesicles are non-resistant to non-ionic detergent. Partial co-staining of Fer1L5 with other two ferlin vesicles, respectively, was observed. Fer1L5 expression was highly detected at the fusion sites of two apposed C2C12 myoblast membranes and its expression level gradually increased at D2 and reached a maximum at day 4 before decreasing during further differentiation. Our studies showed that Fer1L5 has fusion defects during myoblast fusion and impaired membrane repair when the C2C12 cultures were incubated with inhibitory Fer1L5 antibodies. In C2C12 cells Fer1L5 vesicles are involved in two stages, the fusion of myoblasts and the formation of large myotubes. Fer1L5 also plays a role in membrane repair.

scholarly journals Doxycycline Inhibits IL-17-Stimulated MMP-9 Expression by Downregulating ERK1/2 Activation: Implications in Myogenic Differentiation

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hristina Obradović ◽  
Jelena Krstić ◽  
Tamara Kukolj ◽  
Drenka Trivanović ◽  
Ivana Okić Đorđević ◽  
...  
Keyword(s):  
Inflammatory Diseases ◽  
Myogenic Differentiation ◽  
C2c12 Cell ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
Interleukin 17 ◽  
Myoblast Cells ◽  
Pathological Consequence ◽  
Muscle Remodeling

Interleukin 17 (IL-17) is a cytokine with pleiotropic effects associated with several inflammatory diseases. Although elevated levels of IL-17 have been described in inflammatory myopathies, its role in muscle remodeling and regeneration is still unknown. Excessive extracellular matrix degradation in skeletal muscle is an important pathological consequence of many diseases involving muscle wasting. In this study, the role of IL-17 on the expression of matrix metalloproteinase- (MMP-) 9 in myoblast cells was investigated. The expression of MMP-9 after IL-17 treatment was analyzed in mouse myoblasts C2C12 cell line. The increase in MMP-9 production by IL-17 was concomitant with its capacity to inhibit myogenic differentiation of C2C12 cells. Doxycycline (Doxy) treatment protected the myogenic capacity of myoblasts from IL-17 inhibition and, moreover, increased myotubes hypertrophy. Doxy blocked the capacity of IL-17 to stimulate MMP-9 production by regulating IL-17-induced ERK1/2 MAPK activation. Our results imply that MMP-9 mediates IL-17’s capacity to inhibit myoblast differentiation during inflammatory diseases and indicate that Doxy can modulate myoblast response to inflammatory induction by IL-17.

scholarly journals Osteocalcin Induces Proliferation via Positive Activation of the PI3K/Akt, P38 MAPK Pathways and Promotes Differentiation Through Activation of the GPRC6A-ERK1/2 Pathway in C2C12 Myoblast Cells

2017 ◽  
Vol 43 (3) ◽  
pp. 1100-1112 ◽  
Author(s):  
Suifeng Liu ◽  
Feng Gao ◽  
Lei Wen ◽  
Min Ouyang ◽  
Yi Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
P38 Mapk ◽  
C2c12 Cell ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
C2c12 Myoblast ◽  
C2c12 Myoblasts ◽  
Mapk Phosphorylation ◽  
Mapk Pathways ◽  
Myoblast Cells

Background/Aims: Sarcopenia is characterized by an age-related decline in skeletal muscle plus low muscle strength and/or physical performance. Despite the clinical significance of sarcopenia, the molecular pathways underlying sarcopenia remain elusive. The recent demonstration that undercarboxylated osteocalcin (ucOC) favours muscle function related to insulin sensitivity and glucose metabolism raises the question of whether this hormone may also regulate muscle mass. The present study explored the promotive effects of ucOC in proliferation and differentiation processes of C2C12 myoblasts as well as the possible signalling pathways involved. Methods: The effects of exogenous ucOC on C2C12 myoblasts proliferation were assessed using CCK8 and immunohistological staining assays. C2C12 cells were pretreated with PI3K/Akt or P38 MAPK inhibitors to investigate the possible involvement of the PI3K/Akt and P38 MAPK pathways in proliferation. The levels of Akt, phosphorylated-Akt (p-Akt), P38, and phosphorylated-P38 (p-P38) were measured by Western Blotting. The effects of ucOC on myoblast differentiation were quantified by morphological analysis. A silencing experiment was conducted in which the expression of GPRC6A in C2C12 myoblasts was modified. The expression of GPRC6A, myosin heavy chain (MyHC) and the related ERK1/2 signalling pathway in C2C12 myoblasts were monitored by qRT-PCR and Western Blotting. Results: We showed that treatment with exogenous ucOC stimulated the priming of C2C12 myoblasts proliferation. Inhibition of Akt phosphorylation by wortmannin or inhibition of P38 MAPK phosphorylation by SB203580 decreased C2C12 cell proliferation. Wortmannin also reduced P38 MAPK phosphorylation, whereas SB203580 did not affect Akt activation. Furthermore, ucOC promoted C2C12 myoblast differentiation. Inhibition of ERK1/2 phosphorylation with U0126 decreased C2C12 cell differentiation. Finally, GPRC6A expression was substantially increased after ucOC treatment of C2C12 cells. GPRC6A silencing inhibited Akt, P38 MAPK phosphorylation in C2C12 cells, and ERK1/2 phosphorylation in C2C12 myotubes; GPRC6A silencing also decreased cell proliferation, decreased cell differentiation, and downregulated MyHC expression. Conclusions: The present data suggest that ucOC induces myoblast proliferation via sequential activation of the PI3K/Akt and p38 MAPK pathways in C2C12 myoblast cells. Moreover, ucOC enhances myogenic differentiation via a mechanism involving GPRC6A-ERK1/2 signalling.

scholarly journals Biomechanical signals upregulate myogenic gene induction in the presence or absence of inflammation

2007 ◽  
Vol 293 (1) ◽  
pp. C267-C276 ◽  
Author(s):  
Ravi Chandran ◽  
Thomas J. Knobloch ◽  
Mirela Anghelina ◽  
Sudha Agarwal
Keyword(s):  
Cell Differentiation ◽  
Muscle Cell ◽  
Kinase Inhibitor ◽  
Cell Damage ◽  
Myogenic Differentiation ◽  
C2c12 Cell ◽  
Gene Induction ◽  
C2c12 Cells ◽  
Proinflammatory Mediators ◽  
Tnf Α

Inflammation of the muscle invariably leads to muscle cell damage and impaired regeneration. Biomechanical signals play a vital role in the regulation of myogenesis in healthy and inflamed muscle. We hypothesized that biomechanical signals counteract the actions of proinflammatory mediators and upregulate the basic helix-loop-helix and MADS box transcription enhancer factor 2 (MEF2) families of transcription factors, leading to increased myogenesis in inflamed muscle cells. For this purpose, C2C12 cells plated on collagenized silastic membranes were subjected to equibiaxial cyclic tensile strain (CTS) in the presence or absence of TNF-α, and the myogenic gene induction was examined over a period of 72 h. Exposure of cells to CTS resulted in a significant upregulation of mRNA expressions and synthesis of myogenic regulatory factors, MYOD1, myogenin (MYOG), MEF2A, and cyclin-dependent kinase inhibitor 1A (CDKN1A; p21) as well as muscle structural proteins like myosin heavy chain (MYHC) isoforms (MYH1, MYH2, and MYH4) and α-tropomyosin (TPM1), eventually leading to an increase in myotube formation. Contrarily, TNF-α suppressed the expression of all of the above differentiation-inducing factors in C2C12 cells. Further results revealed that simultaneous exposure of C2C12 cells to CTS and TNF-α abrogated the TNF-α-mediated downregulation of myogenic differentiation. In fact, the mRNA expression and protein synthesis of all myogenic factors ( Myod1, Myog, Mef2a, Cdkn1a, Myh1, Myh2, Myh4, and Tpm1) were increased in stretched C2C12 cells despite the sustained presence of TNF-α. These results demonstrate that mechanotransduction regulates multiple signaling molecules involved in C2C12 cell differentiation. On one hand, these signals are potent transducers of myotube phenotype in myoblasts; on the other, these signals counteract catabolic actions of proinflammatory cytokines like TNF-α and allow the expression of myogenic genes to upregulate muscle cell differentiation.

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.

scholarly journals Cell Fusion in Skeletal Muscle: Central Role of NFATC2 in Regulating Muscle Cell Size

Cell Cycle ◽  
2003 ◽  
Vol 2 (5) ◽  
pp. 419-422 ◽  
Author(s):  
Grace K. Pavlath ◽  
Valerie Horsley
Keyword(s):  
Skeletal Muscle ◽  
Cell Size ◽  
Cell Fusion ◽  
Muscle Cell

scholarly journals Agrin-related molecules are concentrated at acetylcholine receptor clusters in normal and aneural developing muscle.

1989 ◽  
Vol 108 (4) ◽  
pp. 1527-1535 ◽  
Author(s):  
J R Fallon ◽  
C E Gelfman
Keyword(s):  
Monoclonal Antibodies ◽  
Muscle Cell ◽  
Acetylcholine Receptors ◽  
External Surface ◽  
Related Molecule ◽  
Whole Mount ◽  
Receptor Clusters ◽  
Alpha Bungarotoxin ◽  
Developing Muscle

Agrin induces the clustering of acetylcholine receptors (AchRs) and other postsynaptic components on the surface of cultured muscle cells. Molecules closely related if not identical to agrin are highly concentrated in the synaptic basal lamina, a structure known to play a key part in orchestrating synapse regeneration. Agrin or agrin-related molecules are thus likely to play a role in directing the differentiation of the postsynaptic apparatus at the regenerating neuromuscular junction. The present studies are aimed at understanding the role of agrin at developing synapses. We have used anti-agrin monoclonal antibodies combined with alpha-bungarotoxin labeling to establish the localization and time of appearance of agrin-related molecules in muscles of the chick hindlimb. Agrinlike immunoreactivity was observed in premuscle masses from as early as stage 23. AchR clusters were first detected late in stage 25, coincident with the entry of axons into the limb. At this and all subsequent stages examined, greater than 95% of the AchR clusters colocalized with agrin-related molecules. This colocalization was also observed in unpermeabilized whole mount preparations, indicating that the agrin-related molecules were disposed on the external surface of the cells. Agrin-related molecules were also detected in regions of low AchR density on the muscle cell surface. To examine the role of innervation in the expression of agrin-related molecules, aneural limbs were generated by two methods. Examination of these limbs revealed that agrin-related molecules were expressed in the aneural muscle and they colocalized with AchR clusters. Thus, in developing muscle, agrin or a closely related molecule (a) is expressed before AchR clusters are detected; (b) is colocalized with the earliest AchR clusters formed; and (c) can be expressed in muscle and at sites of high AchR density independently of innervation. These results indicate that agrin or a related molecule is likely to play a role in synapse development and suggest that the muscle cell may be at least one source of this molecule.

scholarly journals Activated Integrin-Linked Kinase Negatively Regulates Muscle Cell Enhancement Factor 2C in C2C12 Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Zhenguo Dong ◽  
Wei Pan ◽  
Haiqing Wu ◽  
Dongjun Liu ◽  
Ming Cang
Keyword(s):  
Mrna Expression ◽  
Muscle Cell ◽  
Enhancement Factor ◽  
C2c12 Cell ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
Pi3k Activity ◽  
New Ideas ◽  
Integrin Linked Kinase ◽  
Related Proteins

Our previous study reported that muscle cell enhancement factor 2C (MEF2C) was fully activated after inhibition of the phosphorylation activity of integrin-linked kinase (ILK) in the skeletal muscle cells of goats. It enhanced the binding of promoter or enhancer of transcription factor related to proliferation of muscle cells and then regulated the expression of these genes. In the present investigation, we explored whether ILK activation depended on PI3K to regulate the phosphorylation and transcriptional activity of MEF2C during C2C12 cell proliferation. We inhibited PI3K activity in C2C12 with LY294002 and then found that ILK phosphorylation levels and MEF2C phosphorylation were decreased and that MCK mRNA expression was suppressed significantly. After inhibiting ILK phosphorylation activity with Cpd22 and ILK-shRNA, we found MEF2C phosphorylation activity and MCK mRNA expression were increased extremely significantly. In the presence of Cpd22, PI3K activity inhibition increased MEF2C phosphorylation and MCK mRNA expression indistinctively. We conclude that ILK negatively and independently of PI3K regulated MEF2C phosphorylation activity and MCK mRNA expression in C2C12 cells. The results provide new ideas for the study of classical signaling pathway of PI3K-ILK-related proteins and transcription factors.

scholarly journals Evidence of a non-conventional role for the urokinase tripartite complex (uPAR/uPA/PAI-1) in myogenic cell fusion

1997 ◽  
Vol 110 (9) ◽  
pp. 1083-1089 ◽  
Author(s):  
S. Bonavaud ◽  
C. Charriere-Bertrand ◽  
C. Rey ◽  
M.P. Leibovitch ◽  
N. Pedersen ◽  
...  
Keyword(s):  
Cell Migration ◽  
Plasminogen Activator ◽  
Cell Fusion ◽  
Muscle Cell ◽  
Myogenic Cell ◽  
Mrna Levels ◽  
Amino Terminal ◽  
Pai 1

Urokinase can form a tripartite complex binding urokinase receptor (uPAR) and plasminogen activator inhibitor type-1 (PAI-1), a component of the extracellular matrix (ECM). The components of the tripartite complex are modulated throughout the in vitro myogenic differentiation process. A series of experiments aimed at elucidating the role of the urokinase tripartite complex in the fusion of human myogenic cells were performed in vitro. Myogenic cell fusion was associated with increased cell-associated urokinase-type plasminogen activator (uPA) activity, cell-associated uPAR, and uPAR occupancy. Incubation of cultures with either uPA anticatalytic antibodies, or the amino-terminal fragment of uPA (ATF), which inhibits competitively uPA binding to its receptor, or anti-PAI-1 antibodies, which inhibit uPA binding to PAI-1, resulted in a 30 to 47% decrease in fusion. Incubation of cultures with the plasmin inhibitor aprotinin did not affect fusion. Decreased fusion rates induced by interfering with uPAR/uPA/PAI-1 interactions were not associated with significant changes in mRNA levels of both the myogenic regulatory factor myogenin and its inhibitor of DNA binding, Id. Incubation of cultures with purified uPA resulted in a decrease in fusion, likely due to a competitive inhibition of PAI-1 binding of endogenous uPA. We conclude that muscle cell fusion largely depends on interactions between the members of the urokinase complex (uPAR/uPA/PAI-1), but does not require proteolytic activation of plasmin. Since the intrinsic muscle cell differentiation program appears poorly affected by the state of integrity of the urokinase complex, and since cell migration is a prerequisite for muscle cell fusion in vitro, it is likely that the urokinase system is instrumental in fusion through its connection with the cell migration process. Our results suggest that the urokinase tripartite complex may be involved in cell migration in a non conventional way, playing the role of an adhesion system bridging cell membrane to ECM.

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