Satellite cell activation on fibers: modeling events in vivo — an invited review

2004 ◽  
Vol 82 (5) ◽  
pp. 300-310 ◽  
Author(s):  
Judy E Anderson ◽  
Ashley C Wozniak

Knowledge of the events underlying satellite cell activation and the counterpart maintenance of quiescence is essential for planning therapies that will promote the growth and regeneration of skeletal muscle in healthy, disease and aging. By modeling those events of satellite cell activation in studies of single muscle fibers or muscles in culture, the roles of mechanical stretching and nitric oxide are becoming understood. Recent studies demonstrated that stretch-induced activation is very rapid and exhibits some features of satellite cell heterogeneity. As well, gene expression studies showed that expression of the c-met receptor gene rises rapidly after stretching muscles in culture compared to those without stretch. This change in gene expression during activation, and the maintenance of quiescence in both normal and dystrophic muscles are dependent on NO, as they are blocked by inhibition of nitric oxide synthase (NOS). Mechanical, contractile activity is the defining feature of muscle function. Therefore, ongoing studies of stretch effects in satellite cell activation and quiescence in quiescent fiber and muscle cultures provides appropriate models by which to explore the regulatory steps in muscle in vivo under many conditions related to disease, repair, rehabilitation, growth and the prevention or treatment of atrophy.Key words: regeneration, stretch, myofiber culture, muscular dystrophy, quiescence.

2000 ◽  
Vol 11 (5) ◽  
pp. 1859-1874 ◽  
Author(s):  
Judy E. Anderson

Muscle satellite cells are quiescent precursors interposed between myofibers and a sheath of external lamina. Although their activation and recruitment to cycle enable muscle repair and adaptation, the activation signal is not known. Evidence is presented that nitric oxide (NO) mediates satellite cell activation, including morphological hypertrophy and decreased adhesion in the fiber-lamina complex. Activation in vivo occurred within 1 min after injury. Cell isolation and histology showed that pharmacological inhibition of nitric oxide synthase (NOS) activity prevented the immediate injury-induced myogenic cell release and delayed the hypertrophy of satellite cells in that muscle. Transient activation of satellite cells in contralateral muscles 10 min later suggested that a circulating factor may interact with NO-mediated signaling. Interestingly, satellite cell activation in muscles of mdx dystrophic mice and NOS-I knockout mice quantitatively resembled NOS-inhibited release of normal cells, in agreement with reports of displaced and reduced NOS expression in dystrophin-deficient mdx muscle and the complete loss of NOS-I expression in knockout mice. Brief NOS inhibition in normal and mdx mice during injury produced subtle alterations in subsequent repair, including apoptosis in myotube nuclei and myotube formation inside laminar sheaths. Longer NOS inhibition delayed and restricted the extent of repair and resulted in fiber branching. A model proposes the hypothesis that NO release mediates satellite cell activation, possibly via shear-induced rapid increases in NOS activity that produce “NO transients.”


2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Theodora Pavlidou ◽  
Milica Marinkovic ◽  
Marco Rosina ◽  
Claudia Fuoco ◽  
Simone Vumbaca ◽  
...  

The regeneration of the muscle tissue relies on the capacity of the satellite stem cell (SC) population to exit quiescence, divide asymmetrically, proliferate, and differentiate. In age-related muscle atrophy (sarcopenia) and several dystrophies, regeneration cannot compensate for the loss of muscle tissue. These disorders are associated with the depletion of the satellite cell pool or with the loss of satellite cell functionality. Recently, the establishment and maintenance of quiescence in satellite cells have been linked to their metabolic state. In this work, we aimed to modulate metabolism in order to preserve the satellite cell pool. We made use of metformin, a calorie restriction mimicking drug, to ask whether metformin has an effect on quiescence, proliferation, and differentiation of satellite cells. We report that satellite cells, when treated with metformin in vitro, ex vivo, or in vivo, delay activation, Pax7 downregulation, and terminal myogenic differentiation. We correlate the metformin-induced delay in satellite cell activation with the inhibition of the ribosome protein RPS6, one of the downstream effectors of the mTOR pathway. Moreover, in vivo administration of metformin induces a belated regeneration of cardiotoxin- (CTX-) damaged skeletal muscle. Interestingly, satellite cells treated with metformin immediately after isolation are smaller in size and exhibit reduced pyronin Y levels, which suggests that metformin-treated satellite cells are transcriptionally less active. Thus, our study suggests that metformin delays satellite cell activation and differentiation by favoring a quiescent, low metabolic state.


2003 ◽  
Vol 162 (6) ◽  
pp. 1135-1147 ◽  
Author(s):  
Seumas McCroskery ◽  
Mark Thomas ◽  
Linda Maxwell ◽  
Mridula Sharma ◽  
Ravi Kambadur

Satellite cells are quiescent muscle stem cells that promote postnatal muscle growth and repair. Here we show that myostatin, a TGF-β member, signals satellite cell quiescence and also negatively regulates satellite cell self-renewal. BrdU labeling in vivo revealed that, among the Myostatin-deficient satellite cells, higher numbers of satellite cells are activated as compared with wild type. In contrast, addition of Myostatin to myofiber explant cultures inhibits satellite cell activation. Cell cycle analysis confirms that Myostatin up-regulated p21, a Cdk inhibitor, and decreased the levels and activity of Cdk2 protein in satellite cells. Hence, Myostatin negatively regulates the G1 to S progression and thus maintains the quiescent status of satellite cells. Immunohistochemical analysis with CD34 antibodies indicates that there is an increased number of satellite cells per unit length of freshly isolated Mstn−/− muscle fibers. Determination of proliferation rate suggests that this elevation in satellite cell number could be due to increased self-renewal and delayed expression of the differentiation gene (myogenin) in Mstn−/− adult myoblasts. Taken together, these results suggest that Myostatin is a potent negative regulator of satellite cell activation and thus signals the quiescence of satellite cells.


2009 ◽  
Vol 296 (4) ◽  
pp. C922-C929 ◽  
Author(s):  
Ryuichi Tatsumi ◽  
Adam L. Wuollet ◽  
Kuniko Tabata ◽  
Shotaro Nishimura ◽  
Shoji Tabata ◽  
...  

When skeletal muscle is stretched or injured, myogenic satellite cells are activated to enter the cell cycle. This process depends on nitric oxide (NO) production by NO synthase (NOS), matrix metalloproteinase activation, release of hepatocyte growth factor (HGF) from the extracellular matrix, and presentation of HGF to the c-met receptor as demonstrated by a primary culture and in vivo assays. We now add evidence that calcium-calmodulin is involved in the satellite cell activation cascade in vitro. Conditioned medium from cultures that were treated with a calcium ionophore (A23187, ionomycin) for 2 h activated cultured satellite cells and contained active HGF, similar to the effect of mechanical stretch or NO donor treatments. The response was abolished by addition of calmodulin inhibitors (calmidazolium, W-13, W-12) or a NOS inhibitor NG-nitro-l-arginine methyl ester hydrochloride but not by its less inactive enantiomer NG-nitro-d-arginine methyl ester hydrochloride. Satellite cells were also shown to express functional calmodulin protein having a calcium-binding activity at 12 h postplating, which is the time at which the calcium ionophore was added in this study and the stretch treatment was applied in our previous experiments. Therefore, results from these experiments provide an additional insight that calcium-calmodulin mediates HGF release from the matrix and that this step in the activation pathway is upstream from NO synthesis.


2000 ◽  
Vol 278 (1) ◽  
pp. C174-C181 ◽  
Author(s):  
Kristy J. Miller ◽  
Deepa Thaloor ◽  
Sarah Matteson ◽  
Grace K. Pavlath

Hepatocyte growth factor (HGF) is the only known growth factor that activates quiescent satellite cells in skeletal muscle. We hypothesized that local delivery of HGF may enhance regeneration after trauma by increasing the number of myoblasts available for restoring normal tissue architecture. Injection of HGF into muscle at the time of injury increases myoblast number but does not enhance tissue repair as determined using quantitative histological analyses. Rather, depending on the dose and the timing of HGF administration relative to the injury, regeneration can be inhibited. The greatest inhibitory effect is observed when HGF is administered on the day of injury and continued for 3 days, corresponding to the time when satellite cell activation, proliferation, and early differentiation normally occur. To establish a mechanism for this inhibition, we show that HGF can act directly on primary muscle cells to block differentiation. These results demonstrate that 1) exogenous HGF synergizes with factors in damaged muscle to increase myoblast number, 2) regeneration is not regulated solely by myoblast number, and 3) HGF inhibits muscle differentiation both in vitro and in vivo.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lalit Sharma ◽  
Aditi Sharma ◽  
Ashutosh Kumar Dash ◽  
Gopal Singh Bisht ◽  
Girdhari Lal Gupta

Abstract Background Alcohol abuse is a major problem worldwide and it affects people’s health and economy. There is a relapse in alcohol intake due to alcohol withdrawal. Alcohol withdrawal anxiety-like behavior is a symptom that appears 6–24 h after the last alcohol ingestion. Methods The present study was designed to explore the protective effect of a standardized polyherbal preparation POL-6 in ethanol withdrawal anxiety in Wistar rats. POL-6 was prepared by mixing the dried extracts of six plants Bacopa monnieri, Hypericum perforatum, Centella asiatica, Withania somnifera, Camellia sinesis, and Ocimum sanctum in the proportion 2:1:2:2:1:2 respectively. POL-6 was subjected to phytochemical profiling through LC-MS, HPLC, and HPTLC. The effect of POL-6 on alcohol withdrawal anxiety was tested using a two-bottle choice drinking paradigm model giving animals’ free choice between alcohol and water for 15 days. Alcohol was withdrawn on the 16th day and POL-6 (20, 50, and 100 mg/kg, oral), diazepam (2 mg/kg) treatment was given on the withdrawal days. Behavioral parameters were tested using EPM and LDT. On the 18th day blood was collected from the retro-orbital sinus of the rats and alcohol markers ALT, AST, ALP, and GGT were studied. At end of the study, animals were sacrificed and the brain was isolated for exploring the influences of POL-6 on the mRNA expression of GABAA receptor subunits in the amygdala and hippocampus. Results Phytochemical profiling showed that POL-6 contains major phytoconstituents like withaferin A, quercetin, catechin, rutin, caeffic acid, and β-sitosterol. In-vivo studies showed that POL-6 possesses an antianxiety effect in alcohol withdrawal. Gene expression studies on the isolated brain tissues showed that POL-6 normalizes the GABAergic transmission in the amygdala and hippocampus of the rats. Conclusion The study concludes that POL-6 may have therapeutic potential for treating ethanol-type dependence.


Author(s):  
Gerben J. Schaaf ◽  
Tom JM van Gestel ◽  
Esther Brusse ◽  
Robert M. Verdijk ◽  
Irenaeus FM de Coo ◽  
...  

Endocrinology ◽  
2003 ◽  
Vol 144 (3) ◽  
pp. 839-849 ◽  
Author(s):  
Buffy S. Ellsworth ◽  
Brett R. White ◽  
Ann T. Burns ◽  
Brian D. Cherrington ◽  
Annette M. Otis ◽  
...  

Reproductive function is dependent on the interaction between GnRH and its cognate receptor found on gonadotrope cells of the anterior pituitary gland. GnRH activation of the GnRH receptor (GnRHR) is a potent stimulus for increased expression of multiple genes including the gene encoding the GnRHR itself. Thus, homologous regulation of the GnRHR is an important mechanism underlying gonadotrope sensitivity to GnRH. Previously, we have found that GnRH induction of GnRHR gene expression in αT3-1 cells is partially mediated by protein kinase C activation of a canonical activator protein-1 (AP-1) element. In contrast, protein kinase A and a cAMP response element-like element have been implicated in mediating the GnRH response of the GnRHR gene using a heterologous cell model (GGH3). Herein we find that selective removal of the canonical AP-1 site leads to a loss of GnRH regulation of the GnRHR promoter in transgenic mice. Thus, an intact AP-1 element is necessary for GnRH responsiveness of the GnRHR gene both in vitro and in vivo. Based on in vitro analyses, GnRH appeared to enhance the interaction of JunD, FosB, and c-Fos at the GnRHR AP-1 element. Although enhanced binding of cFos reflected an increase in gene expression, GnRH appeared to regulate both FosB and JunD at a posttranslational level. Neither overexpression of a constitutively active Raf-kinase nor pharmacological blockade of GnRH-induced ERK activation eliminated the GnRH response of the GnRHR promoter. GnRH responsiveness was, however, lost in αT3-1 cells that stably express a dominant-negative c-Jun N-terminal kinase (JNK) kinase, suggesting a critical role for JNK in mediating GnRH regulation of the GnRHR gene. Consistent with this possibility, we find that the ability of forskolin and membrane-permeable forms of cAMP to inhibit the GnRH response of the GnRHR promoter is associated with a loss of both JNK activation and GnRH-mediated recruitment of the primary AP-1-binding components.


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