Anisotropic regulation of Ankrd2 gene expression in skeletal muscle by mechanical stretch

FASEB J. 2010 Sep;24(9):3330-40. doi: 10.1096/fj.10-158386. Epub 2010 May 4.

Abstract

The diaphragm muscles in vivo are subjected to mechanical forces both in the direction of the muscle fibers and in the direction transverse to the fibers. However, the effect of directional mechanical forces in skeletal muscle gene regulation is completely unknown. Here, we identified that stretch in the longitudinal and transverse directions to the diaphragm muscle fibers up-regulated Ankrd2 gene expression by two distinct signaling pathways in wild-type (WT) and mdm, a mouse model of muscular dystrophy with early-onset of progressive muscle-wasting. Stretch in the longitudinal direction activated both NF-kappaB and AP-1 transcription factors, whereas stretch in the transverse direction activated only AP-1 transcription factor. Interestingly, longitudinal stretch activated Ankrd2 promoter only by NF-kappaB, whereas transverse stretch activated Ankrd2 promoter by AP-1. Moreover, we found that longitudinal stretch activated Akt, which up-regulated Ankrd2 expression through NF-kappaB. However, transverse stretch activated Ras-GTP, Raf-1, and Erk1/2 proteins, which up-regulated Ankrd2 expression through AP-1. Surprisingly, the stretch-activated NF-kappaB and AP-1 signaling pathways was not involved in Ankrd2 regulation at the basal level, which was high in the mdm mouse diaphragm. Taken together, our data show the anisotropic regulation of Ankrd2 gene expression in the diaphragm muscles of WT and mdm mice via two distinct mechanosensitive signaling pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Blotting, Western
  • Chromatin Immunoprecipitation
  • Diaphragm / metabolism
  • Gene Expression Regulation* / genetics
  • Gene Expression Regulation* / physiology
  • In Vitro Techniques
  • Mice
  • Mice, Inbred C57BL
  • Muscle Proteins / genetics
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism*
  • Muscular Dystrophy, Animal
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Stress, Mechanical*
  • Transcription Factor AP-1 / metabolism

Substances

  • Ankrd2 protein, mouse
  • Muscle Proteins
  • NF-kappa B
  • Transcription Factor AP-1
  • Proto-Oncogene Proteins c-akt