Nerve activity-independent regulation of skeletal muscle atrophy: Role of MyoD and myogenin in satellite cells and myonuclei

Jon-Philippe Hyatt, Roland R. Roy, Kenneth M. Baldwin, V. Reggie Edgerton

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

Electrical activity is thought to be the primary neural stimulus regulating muscle mass, expression of myogenic regulatory factor genes, and cellular activity within skeletal muscle. However, the relative contribution of neural influences that are activity-dependent and -independent in modulating these characteristics is unclear. Comparisons of denervation (no neural influence) and spinal cord isolation (SI, neural influence with minimal activity) after 3, 14, and 28 days of treatment were used to demonstrate whether there are neural influences on muscle that are activity independent. Furthermore, the effects of these manipulations were compared for a fast ankle extensor (medial gastrocnemius) and a fast ankle flexor (tibialis anterior). The mass of both muscles plateaued at ∼60% of control 2 wk after SI, whereas both muscles progressively atrophied to <25% of initial mass at this same time point after denervation. A rapid increase in myogenin and, to a lesser extent, MyoD mRNAs and proteins was observed in denervated and SI muscles: at the later time points, these myogenic regulatory factors remained elevated in denervated, but not in SI, muscles. This widespread neural activity-independent influence on MyoD and myogenin expression was observed in myonuclei and satellite cells and was not specific for fast or slow fiber phenotypes. Mitotic activity of satellite and connective tissue cells also was consistently lower in SI than in denervated muscles. These results demonstrate a neural effect independent of electrical activity that 1) helps preserve muscle mass, 2) regulates muscle-specific genes, and 3) potentially spares the satellite cell pool in inactive muscles.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume285
Issue number5 54-5
StatePublished - Nov 2003
Externally publishedYes

Fingerprint

Myogenin
Muscular Atrophy
Muscle
Skeletal Muscle
Satellites
Muscles
Myogenic Regulatory Factors
Denervation
Ankle
MyoD Protein
Genes
Connective Tissue Cells
Regulator Genes
Spinal Cord

Keywords

  • Bromodeoxyuridine
  • Denervation
  • Myogenic regulatory factor
  • Spinal cord isolation

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Nerve activity-independent regulation of skeletal muscle atrophy : Role of MyoD and myogenin in satellite cells and myonuclei. / Hyatt, Jon-Philippe; Roy, Roland R.; Baldwin, Kenneth M.; Edgerton, V. Reggie.

In: American Journal of Physiology - Cell Physiology, Vol. 285, No. 5 54-5, 11.2003.

Research output: Contribution to journalArticle

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