Regulation of Skeletal Muscle Myoblast Differentiation and Proliferation by Pannexins

Author(s):  
Stéphanie Langlois ◽  
Kyle N. Cowan
2008 ◽  
Vol 369 (4) ◽  
pp. 1094-1097 ◽  
Author(s):  
Meritxell Roura-Ferrer ◽  
Laura Solé ◽  
Ramón Martínez-Mármol ◽  
Núria Villalonga ◽  
Antonio Felipe

2000 ◽  
Vol 279 (5) ◽  
pp. C1656-C1664 ◽  
Author(s):  
B. Paul Herring ◽  
Shelley Dixon ◽  
Patricia J. Gallagher

The purpose of this study was to characterize myosin light chain kinase (MLCK) expression in cardiac and skeletal muscle. The only classic MLCK detected in cardiac tissue, purified cardiac myocytes, and in a cardiac myocyte cell line (AT1) was identical to the 130-kDa smooth muscle MLCK (smMLCK). A complex pattern of MLCK expression was observed during differentiation of skeletal muscle in which the 220-kDa-long or “nonmuscle” form of MLCK is expressed in undifferentiated myoblasts. Subsequently, during myoblast differentiation, expression of the 220-kDa MLCK declines and expression of this form is replaced by the 130-kDa smMLCK and a skeletal muscle-specific isoform, skMLCK in adult skeletal muscle. These results demonstrate that the skMLCK is the only tissue-specific MLCK, being expressed in adult skeletal muscle but not in cardiac, smooth, or nonmuscle tissues. In contrast, the 130-kDa smMLCK is ubiquitous in all adult tissues, including skeletal and cardiac muscle, demonstrating that, although the 130-kDa smMLCK is expressed at highest levels in smooth muscle tissues, it is not a smooth muscle-specific protein.


Author(s):  
Paul J. Rozance ◽  
Stephanie R Wesolowski ◽  
Sonnet S. Jonker ◽  
Laura D Brown

Fetal skeletal muscle growth requires myoblast proliferation, differentiation, and fusion into myofibers in addition to protein accretion for fiber hypertrophy. Oxygen is an important regulator of this process. Therefore, we hypothesized that fetal anemic hypoxemia would inhibit skeletal muscle growth. Studies were performed in late gestation fetal sheep that were bled to anemic, and therefore hypoxemic, conditions beginning at ~125 days of gestation (term = 148 days) for 9 ± 0 days (n=19) and compared to control fetuses (n=16). A metabolic study was performed on gestational day ~134 to measure fetal protein kinetic rates. Myoblast proliferation and myofiber area were determined in biceps femoris (BF), tibialis anterior (TA), and flexor digitorum superficialis (FDS) muscles. mRNA expression of muscle regulatory factors was determined in BF. Fetal arterial hematocrit and oxygen content were 28% and 52% lower, respectively, in anemic fetuses. Fetal weight and whole-body protein synthesis, breakdown, and accretion rates were not different between groups. Hindlimb length, however, was 7% shorter in anemic fetuses. TA and FDS muscles weighed less and FDS myofiber area was smaller in anemic fetuses compared to controls. The percentage of Pax7+ myoblasts that expressed Ki67 was lower in BF and tended to be lower in FDS from anemic fetuses indicating reduced myoblast proliferation. There was less MYOD and MYF6 mRNA expression in anemic vs. control BF consistent with reduced myoblast differentiation. These results indicate that fetal anemic hypoxemia reduced muscle growth. We speculate that fetal muscle growth may be improved by strategies that increase oxygen availability.


2018 ◽  
Vol 15 (1) ◽  
pp. 48-58 ◽  
Author(s):  
Janaina M. Alves ◽  
Antonio H. Martins ◽  
Claudiana Lameu ◽  
Talita Glaser ◽  
Nawal M. Boukli ◽  
...  

2008 ◽  
Vol 20 (4) ◽  
pp. 497 ◽  
Author(s):  
W.-Y. Tse ◽  
S. C. Town ◽  
G. K. Murdoch ◽  
S. Novak ◽  
M. K. Dyck ◽  
...  

Uterine crowding in the pig results in intrauterine growth restriction (IUGR), and permanently affects fetal muscle fibre development, representing production losses for the commercial pig herd. The present study sought to understand how different levels of uterine crowding in sows affects muscle fibre development in the early embryo at the time of muscle fibre differentiation and proliferation. Sows either underwent surgical, unilateral oviduct ligation (LIG; n = 10) to reduce the number of embryos in the uterus, or remained as intact, relatively-crowded controls (CTR; n = 10). Embryos and placentae were collected at Day 30 of gestation, and myogenic regulatory factor (MRF) transcript abundance was determined using real-time PCR for both myogenin (MYOG) and myoblast differentiation 1 (MYOD1). Unilateral tubal ligation resulted in lower numbers of embryos in utero, higher placental weights and a higher male : female sex ratio (P < 0.05). Relative MYOD1 expression was not different, but MYOG expression was higher (P < 0.05) in the LIG group embryos; predominantly due to effects on the male embryos. Relatively modest uterine crowding therefore affects MRF expression, even at very early stages of embryonic development, and could contribute to reported differences in fetal muscle fibre development, birthweight and thus post-natal growth performance in swine.


2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Luigi Anastasia ◽  
Raffaella Scaringi ◽  
Nadia Papini ◽  
Andrea Garatti ◽  
Lorenzo Menicanti ◽  
...  

Membrane-bound sialidase NEU3 increase during skeletal muscle differentiation has been shown to protect myoblasts from apoptosis and drive the differentiation process [1]. Thus, the objective of this study was to assess whether up-regulation of NEU3 would enhance the ability of murine skeletal muscle cells to resist to hypoxia, ultimately opposing cell death. We found that C2C12 myoblasts overexpressing NEU3 (L-NEU3) became highly resistant to 1% oxygen or 200 mM deferoxamine induced hypoxia. Moreover, L-NEU3 myoblasts survived a seven-day treatment of combined hypoxia and low serum (2% horse serum used to induce myoblast differentiation), without any significant cell loss. On the contrary, wild type C2C12 could not resist to these culturing conditions and all died within 48h. Real Time PCR showed NEU3 expression increase during all hypoxic treatments both in C2C12 and L-NEU3 cells, suggesting an endogenous NEU3 activation under these conditions. Moreover, we found that NEU3 over-expression activated pro-survival signalling pathways through up-regulation and activation of EGF receptor. Overall, our data support the hypothesis that NEU3 may play a critical role in the response of skeletal myoblasts to hypoxia and the preservation of cell viability by activating pro-survival signalling pathways. [1] Anastasia L. et al. J.Biol.Chem. 2008, 283 (52): 36265–36271.


Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2349-2358 ◽  
Author(s):  
A. Rawls ◽  
M.R. Valdez ◽  
W. Zhang ◽  
J. Richardson ◽  
W.H. Klein ◽  
...  

The myogenic basic helix-loop-helix (bHLH) genes - MyoD, Myf5, myogenin and MRF4 - exhibit distinct, but overlapping expression patterns during development of the skeletal muscle lineage and loss-of-function mutations in these genes result in different effects on muscle development. MyoD and Myf5 have been shown to act early in the myogenic lineage to establish myoblast identity, whereas myogenin acts later to control myoblast differentiation. In mice lacking myogenin, there is a severe deficiency of skeletal muscle, but some residual muscle fibers are present in mutant mice at birth. Mice lacking MRF4 are viable and have skeletal muscle, but they upregulate myogenin expression, which could potentially compensate for the absence of MRF4. Previous studies in which Myf5 and MRF4 null mutations were combined suggested that these genes do not share overlapping myogenic functions in vivo. To determine whether the functions of MRF4 might overlap with those of myogenin or MyoD, we generated double mutant mice lacking MRF4 and either myogenin or MyoD. MRF4/myogenin double mutant mice contained a comparable number of residual muscle fibers to mice lacking myogenin alone and myoblasts from those double mutant mice formed differentiated multinucleated myotubes in vitro as efficiently as wild-type myoblasts, indicating that neither myogenin nor MRF4 is absolutely essential for myoblast differentiation. Whereas mice lacking either MRF4 or MyoD were viable and did not show defects in muscle development, MRF4/MyoD double mutants displayed a severe muscle deficiency similar to that in myogenin mutants. Myogenin was expressed in MRF4/MyoD double mutants, indicating that myogenin is insufficient to support normal myogenesis in vivo. These results reveal unanticipated compensatory roles for MRF4 and MyoD in the muscle differentiation pathway and suggest that a threshold level of myogenic bHLH factors is required to activate muscle structural genes, with this level normally being achieved by combinations of multiple myogenic bHLH factors.


1994 ◽  
Vol 107 (3) ◽  
pp. 487-496 ◽  
Author(s):  
I. Guillet-Deniau ◽  
A. Leturque ◽  
J. Girard

Skeletal muscle regeneration is mediated by the proliferation of myoblasts from stem cells located beneath the basal lamina of myofibres, the muscle satellite cells. They are functionally indistinguishable from embryonic myoblasts. The myogenic process includes the fusion of myoblasts into multinucleated myotubes, the biosynthesis of proteins specific for skeletal muscle and proteins that regulates glucose metabolism, the glucose transporters. We find that three isoforms of glucose transporter are expressed during foetal myoblast differentiation: GLUT1, GLUT3 and GLUT4; their relative expression being dependent upon the stage of differentiation of the cells. GLUT1 mRNA and protein were abundant only in myoblasts from 19-day-old rat foetuses or from adult muscles. GLUT3 mRNA and protein, detectable in both cell types, increased markedly during cell fusion, but decreased in contracting myotubes. GLUT4 mRNA and protein were not expressed in myoblasts. They appeared only in spontaneously contracting myotubes cultured on an extracellular matrix. Insulin or IGF-I had no effect on the expression of the three glucose transporter isoforms, even in the absence of glucose. The rate of glucose transport, assessed using 2-[3H]deoxyglucose, was 2-fold higher in myotubes than in myoblasts. Glucose deprivation increased the basal rate of glucose transport by 2-fold in myoblasts, and 4-fold in myotubes. The cellular localization of the glucose transporters was directly examined by immunofluorescence staining. GLUT1 was located on the plasma membrane of myoblasts and myotubes. GLUT3 was located intracellularly in myoblasts and appeared also on the plasma membrane in myotubes. Insulin or IGF-I were unable to target GLUT3 to the plasma membrane. GLUT4, the insulin-regulatable glucose transporter isoform, appeared only in contracting myotubes in small intracellular vesicles. It was translocated to the plasma membrane after a short exposure to insulin, as it is in skeletal muscle in vivo. These results show that there is a switch in glucose transporter isoform expression during myogenic differentiation, dependent upon the energy required by the different stages of the process. GLUT3 seemed to play a role during cell fusion, and could be a marker for the muscle's ability to regenerate.


2020 ◽  
Vol 396 (2) ◽  
pp. 112297
Author(s):  
Fei-Hu Lin ◽  
Anmin Wang ◽  
Wuhou Dai ◽  
Song Chen ◽  
Yahui Ding ◽  
...  

2019 ◽  
Vol 20 (20) ◽  
pp. 5130 ◽  
Author(s):  
Shunshun Han ◽  
Can Cui ◽  
Haorong He ◽  
Xiaoxu Shen ◽  
Yuqi Chen ◽  
...  

Myoferlin (MyoF), which is a calcium/phospholipid-binding protein expressed in cardiac and muscle tissues, belongs to the ferlin family. While MyoF promotes myoblast differentiation, the underlying mechanisms remain poorly understood. Here, we found that MyoF not only promotes C2C12 myoblast differentiation, but also inhibits muscle atrophy and autophagy. In the present study, we found that myoblasts fail to develop into mature myotubes due to defective differentiation in the absence of MyoF. Meanwhile, MyoF regulates the expression of atrophy-related genes (Atrogin-1 and MuRF1) to rescue muscle atrophy. Furthermore, MyoF interacts with Dishevelled-2 (Dvl-2) to activate canonical Wnt signaling. MyoF facilitates Dvl-2 ubiquitination resistance by reducing LC3-labeled Dvl-2 levels and antagonizing the autophagy system. In conclusion, we found that MyoF plays an important role in myoblast differentiation during skeletal muscle atrophy. At the molecular level, MyoF protects Dvl-2 against autophagy-mediated degradation, thus promoting activation of the Wnt/β-catenin signaling pathway. Together, our findings suggest that MyoF, through stabilizing Dvl-2 and preventing autophagy, regulates Wnt/β-catenin signaling-mediated skeletal muscle development.


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