Day-Night Oscillation of Atrogin1 and Timing-Dependent Preventive Effect of Weight-Bearing on Muscle Atrophy

EBioMedicine. 2018 Nov;37:499-508. doi: 10.1016/j.ebiom.2018.10.057. Epub 2018 Nov 1.


Background: Atrogin1, which is one of the key genes for the promotion of muscle atrophy, exhibits day-night variation. However, its mechanism and the role of its day-night variation are largely unknown in a muscle atrophic context.

Methods: The mice were induced a muscle atrophy by hindlimb-unloading (HU). To examine a role of circadian clock, Wild-type (WT) and Clock mutant mice were used. To test the effects of a neuronal effects, an unilateral ablation of sciatic nerve was performed in HU mice. To test a timing-dependent effects of weight-bearing, mice were released from HU for 4 h in a day at early or late active phase (W-EAP and W-LAP groups, respectively).

Findings: We found that the day-night oscillation of Atrogin1 expression was not observed in Clock mutant mice or in the sciatic denervated muscle. In addition, the therapeutic effects of weight-bearing were dependent on its timing with a better effect in the early active phase.

Interpretation: These findings suggest that the circadian clock controls the day-night oscillation of Atrogin1 expression and the therapeutic effects of weight-bearing are dependent on its timing. FUND: Council for Science, Technology, and Innovation, SIP, "Technologies for creating next-generation agriculture, forestry, and fisheries".

Keywords: Atrogin1; Chrono-exercise; Circadian rhythm; Hindlimb-unloading; Weight-bearing.

MeSH terms

  • Animals
  • Circadian Rhythm*
  • Gene Expression Regulation*
  • Male
  • Mice
  • Mice, Inbred ICR
  • Mice, Mutant Strains
  • Muscle Proteins / biosynthesis*
  • Muscle Proteins / genetics
  • Muscular Atrophy / genetics
  • Muscular Atrophy / metabolism*
  • Muscular Atrophy / pathology
  • Muscular Atrophy / therapy
  • Physical Conditioning, Animal*
  • SKP Cullin F-Box Protein Ligases / biosynthesis*
  • SKP Cullin F-Box Protein Ligases / genetics
  • Weight-Bearing


  • Muscle Proteins
  • Fbxo32 protein, mouse
  • SKP Cullin F-Box Protein Ligases