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Home / Equine Research Bank / J Anim Sci / Cultured equine satellite cells as a model system to assess ...
Journal of animal science2018; 96(1); 143-153; doi: 10.1093/jas/skx028

Cultured equine satellite cells as a model system to assess leucine stimulated protein synthesis in horse muscle.

Abstract: Leucine has been shown to stimulate the mammalian/mechanistic target of rapamycin (mTOR) signaling pathway which plays numerous key regulatory roles in cell growth, survival, and metabolism including protein synthesis in a number of species. However, previous work with equine satellite cells has suggested distinct species differences in regards to physiological effects and the magnitude of responses to growth factors and regulators. Because there is limited research available regarding the role of leucine in regulating equine skeletal muscle protein synthesis, the objective of this study was to evaluate the effect of leucine on the mTOR signaling pathway in cultured equine satellite. Protein synthesis was evaluated by measuring the incorporation of [3H] Phenylalanine (3HPhe) in equine satellite cell myotube cultures treated with a leucine titration ranging from 0 to 408 µM. Our results show a 1.8-fold increase (P < 0.02) in protein synthesis at levels slightly greater than those found in the general circulation, 204 and 408 µM when compared to a no leucine control (0 µM). Puromycin incorporation, a nonradioactive surface sensing of translation (SUnSET) methodology, was also measured in cells treated with leucine (LEU; 408 µM), a no-leucine control (CON), and a puromycin-negative vehicle (PURO-). These results demonstrated a 180% increase (P = 0.0056) in puromycin incorporation in LEU compared to CON cultures. To evaluate the mTOR signaling pathway, equine satellite cell myotube cultures were treated with leucine (LEU; 408 µM) or a no-leucine control (CON) in the presence or absence of rapamycin (LR and CR, respectively), an inhibitor of mTOR. The mTOR inhibitor, rapamycin, suppressed phosphorylation of mTOR (P < 0.01) and rS6 (P < 0.01) with an increase in phosphorylation of rS6 in leucine-treated cultures observed when compared to control cultures (P < 0.05). Similarly, there was a 27% increase (P < 0.005) in the hyperphosphorylated γ-form of 4E-BP1 compared to total 4E-BP1 in LEU compared to CON cultures with leucine-induced phosphorylation of 4E-BP1 completely blocked by rapamycin with a smaller decrease observed in CR compared to CON cultures. The major finding of this study was that leucine activated the mTOR translation initiation pathway and increased transcription of global proteins in cultured equine satellite cells. Use of the cell culture system with primary equine muscle cell lines provides the opportunity to distinguish the impact of leucine on muscle and protein synthesis, independent of systemic interactions.
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Publication Date: 2018-02-15 PubMed ID: 29444251PubMed Central: PMC6140856DOI: 10.1093/jas/skx028Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The objective of this research was to explore the effects of leucine, an amino acid, on protein synthesis in horse muscle cells. The results revealed that leucine activates a mechanism involved in protein synthesis and increases the overall protein production in these cells, opening up new avenues for further exploration.

Objective of the Study

  • The main goal of this research was to examine the impact of leucine on the mammalian/mechanistic target of rapamycin (mTOR) signaling pathway in cultured equine satellite cells. The mTOR pathway is involved in regulating cell growth, survival, and metabolism, including protein synthesis.

Methodology

  • The researchers exposed equine satellite cell myotube cultures to varying concentrations of leucine, ranging from 0 to 408 µM.
  • They then used two methods – the incorporation of [3H] Phenylalanine (3HPhe) and the nonradioactive surface sensing of translation (SUnSET) methodology – to measure protein synthesis.
  • Additionally, they used the mTOR inhibitor, rapamycin, to assess the role of this pathway in the leucine-induced protein synthesis.

Results

  • The study found a 1.8-fold increase in protein synthesis at slightly greater concentrations than those found in the general circulation (204 and 408 µM) when compared to a control with no leucine.
  • They also observed a 180% rise in puromycin incorporation in leucine-treated cultures compared to the control cultures.
  • The inhibitor rapamycin was found to suppress the phosphorylation of mTOR and rS6, key proteins in the mTOR signaling pathway. This suppression was mitigated in leucine-treated cultures, indicating that leucine plays a role in activating this pathway.

Major Findings and Implication

  • The primary finding was that leucine activates the mTOR translation initiation pathway and enhances the transcription of global proteins in cultured equine satellite cells. In other words, leucine appears to stimulate protein production in these cells.
  • By using cultured equine muscle cell lines, researchers can effectively study the influence of leucine on muscle and protein synthesis, independent of systemic interactions. This approach presents opportunities for potential breakthroughs in muscle health and recovery in horses.

Cite This Article

APA
DeBoer ML, Martinson KM, Pampusch MS, Hansen AM, Wells SM, Ward C, Hathaway M. (2018). Cultured equine satellite cells as a model system to assess leucine stimulated protein synthesis in horse muscle. J Anim Sci, 96(1), 143-153. https://doi.org/10.1093/jas/skx028

Publication

Journal of animal science
ISSN: 1525-3163
NlmUniqueID: 8003002
Country: United States
Language: English
Volume: 96
Issue: 1
Pages: 143-153

Researcher Affiliations

DeBoer, Michelle L
  • Department of Animal Science, University of Minnesota, St. Paul, MN.
Martinson, Krishona M
  • Department of Animal Science, University of Minnesota, St. Paul, MN.
Pampusch, Mary S
  • Department of Veterinary Biomedical Sciences, University of Minnesota, St. Paul, MN.
Hansen, Abigail M
  • College of Veterinary Medicine, University of Minnesota, St. Paul, MN.
Wells, Scott M
  • Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN.
Ward, Christie
  • Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN.
Hathaway, Marcia
  • Department of Animal Science, University of Minnesota, St. Paul, MN.

MeSH Terms

  • Animals
  • Cell Line
  • Cells, Cultured
  • Horses / metabolism
  • Leucine / pharmacology
  • Models, Biological
  • Muscle Fibers, Skeletal / drug effects
  • Muscle Fibers, Skeletal / metabolism
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism
  • Phosphorylation / drug effects
  • Protein Biosynthesis / drug effects
  • Puromycin / metabolism
  • Satellite Cells, Skeletal Muscle / drug effects
  • Satellite Cells, Skeletal Muscle / metabolism
  • Signal Transduction / drug effects
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases / drug effects
  • TOR Serine-Threonine Kinases / metabolism

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Citations

This article has been cited 9 times.
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