Potential role for Id myogenic repressors in apoptosis and attenuation of hypertrophy in muscles of aged rats

Stephen Alway, Hans Degens, Gururaj Krishnamurthy, Cheryl A. Smith

Research output: Contribution to journalArticle

117 Citations (Scopus)

Abstract

Aging attenuates the overload-induced increase in myogenic regulatory transcription factor (MRF) expression and the extent of muscle enlargement. To identify whether mRNA levels of repressors of the MRFs are greater in overloaded muscles from aged animals, overload was achieved in plantaris muscle of aged (33 mo; n = 14) and adult (9 mo; n = 17) rats. After 14 days, plantaris muscles in the overloaded limb were ∼25% and 6% larger in adult and aged rats, respectively, compared with the contralateral limb. Hypertrophied muscles of adult rats had significantly greater levels of mRNA and protein levels for myogenin and MyoD compared with control muscles, but neither MRF increased with overload in muscles of aged rats. Muscles of aged rats had greater Id mRNA (150-700%) and protein repressor (200-6,000%) levels compared with adult rats. BAX and caspase 9 protein levels were 9,500% and 300% greater, respectively, in both control and hypertrophied muscles of aged rats compared with young adult rats. These data are consistent with the hypothesis that aging increases Id transcripts that activate apoptotic pathways involving BAX. This may contribute to sarcopenia by attenuating MRF protein levels in muscles of old animals.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume283
Issue number1 52-1
StatePublished - Jul 3 2002
Externally publishedYes

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Hypertrophy
Apoptosis
Muscles
Myogenic Regulatory Factors
Transcription Factors
Messenger RNA
Skeletal Muscle
Extremities
Myogenin
Sarcopenia
Repressor Proteins
Proteins
Caspase 9
Young Adult

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Cite this

Potential role for Id myogenic repressors in apoptosis and attenuation of hypertrophy in muscles of aged rats. / Alway, Stephen; Degens, Hans; Krishnamurthy, Gururaj; Smith, Cheryl A.

In: American Journal of Physiology - Cell Physiology, Vol. 283, No. 1 52-1, 03.07.2002.

Research output: Contribution to journalArticle

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