Acute mechanical overload increases IGF-I and MMP-9 mRNA in 3D tissue-engineered skeletal muscle

Biotechnol Lett. 2014 May;36(5):1113-24. doi: 10.1007/s10529-014-1464-y. Epub 2014 Feb 22.

Abstract

Skeletal muscle (SkM) is a tissue that responds to mechanical load following both physiological (exercise) or pathophysiological (bed rest) conditions. The heterogeneity of human samples and the experimental and ethical limitations of animal studies provide a rationale for the study of SkM plasticity in vitro. Many current in vitro approaches of mechanical loading of SkM disregard the three-dimensional (3D) structure in vivo. Tissue engineered 3D SkM, that displays highly aligned and differentiated myotubes, was used to investigate mechano-regulated gene transcription of genes implicated in hypertrophy/atrophy. Static loading (STL) and ramp loading (RPL) at 10 % strain for 60 min were used as mechano-stimulation with constructs sampled immediately for RNA extraction. STL increased IGF-I mRNA compared to both RPL and CON (control, p = 0.003 and 0.011 respectively) whilst MMP-9 mRNA increased in STL and RPL compared to CON (both p < 0.05). IGFBP-2 mRNA was differentially regulated in RPL and STL compared to CON (p = 0.057), whilst a reduction in IGFBP-5 mRNA was found for STL and RPL compared to CON (both p < 0.05). There was no effect in the expression of putative atrophic genes, myostatin, MuRF-1 and MAFBx (all p > 0.05). These data demonstrate a transcriptional signature associated with SkM hypertrophy within a tissue-engineered model that more greatly recapitulates the in vivo SkM structure compared previously published studies.

MeSH terms

  • Animals
  • Biomechanical Phenomena / physiology*
  • Cell Line
  • Insulin-Like Growth Factor I / analysis
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / metabolism*
  • Matrix Metalloproteinase 9 / analysis
  • Matrix Metalloproteinase 9 / genetics
  • Matrix Metalloproteinase 9 / metabolism*
  • Mice
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / physiology*
  • Myoblasts
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Stress, Mechanical
  • Tissue Engineering

Substances

  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Matrix Metalloproteinase 9