Gene and protein expression associated with protein synthesis and breakdown in paraplegic skeletal muscle

Micah J. Drummond, Erin L. Glynn, Heidi L. Lujan, Stephen E. Dicarlo, Blake B. Rasmussen

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Spinal cord injury reduces the rate of skeletal muscle protein synthesis and increases protein breakdown, resulting in rapid muscle loss. The purpose of this study was to determine whether long-term paraplegia would eventually result in a downregulation of muscle mRNA and protein expression associated with both protein synthesis and breakdown. After 10 weeks of spinal cord transection, soleus muscle from 12 rats (6 sham-control, 6 paraplegic) was studied for mRNAs and proteins associated with protein synthesis and breakdown using real-time polymerase chain reaction and immunoblotting techniques. Protein kinase B (PKB/Akt), ribosomal S6 kinase 1 (S6K1), and myogenin mRNA were downregulated, whereas muscle ring finger 1 (MuRF1) and phospho-forkhead transcription factor 4 (FoxO4) protein were increased in paraplegic rats. We conclude that gene and protein expression of pathways associated with protein synthesis are reduced, whereas some markers of protein breakdown remain elevated following chronic paraplegia. Clinical interventions designed to increase muscle protein synthesis may be helpful in preventing excessive muscle loss during long-term paraplegia.

Original languageEnglish (US)
Pages (from-to)505-513
Number of pages9
JournalMuscle and Nerve
Volume37
Issue number4
DOIs
StatePublished - Apr 2008

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Keywords

  • Chronic atrophy
  • FoxO
  • MuRF1
  • Spinal cord injury
  • mTOR

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)

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