Celastrol overcomes HSP72 gene silencing-mediated muscle atrophy and induces myofiber preservation

T. Gwag, K. Park, Junsoo Park, J. H. Lee, T. Nikawa, Inho Choi

Research output: Contribution to journalArticle

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Abstract

To elucidate a potential anabolic role of heat shock proteins (HSPs) in myofiber preservation, we assessed the effect of HSP70 gene silencing versus its overexpression on skeletal muscle atrophy or rescue. HSP72 gene expression was silenced by pre-treatment with HSP72 siRNA in cultured rat L6 myotubes, and the pro-anabolic effect of HSPs was examined in the absence or presence of the HSP inducer celastrol (CEL). Compared to the negative control (NC), both nuclear accumulation and phosphorylation of heat shock transcription factor 1 remained high under the 6-h treatment of CEL. The HSP72 siRNA treatment significantly decreased HSP72 mRNA and protein expression and myotube diameter. CEL treatment, however, markedly increased the HSP72 expression and rendered the myotube size recovered to the NC level even in the siRNA-treated cells. Moreover, the HSP72 siRNA upregulated forkhead box O3 (FoxO3) expression in the nucleus while CEL increased p-FoxO3 exclusively in the cytoplasm, thus leaving the p-FoxO3/FoxO3 balanced to the NC level by siRNA + CEL treatment. The atrophic effect of HSP72 siRNA was consistent with the upregulation of atrogin-1 and proteasome activity but CEL treatment abrogated such effect by activation of Akt1, ribosomal S6 kinase (S6K) and extracellular signal-regulated kinase 1/2 (ERK1/2), irrespective of HSP72 silencing. These results suggest that CEL-mediated overexpression of HSP72 overcomes the atrophic effect of HSP72 gene silencing via both enhancement of FoxO3 phosphorylation and activation of Akt1-ERK1/2 signaling pathway.

Original languageEnglish
Pages (from-to)273-283
Number of pages11
JournalJournal of Physiology and Pharmacology
Volume66
Issue number2
Publication statusPublished - 2015 Jan 1

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Muscular Atrophy
Gene Silencing
Small Interfering RNA
Skeletal Muscle Fibers
Heat-Shock Proteins
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinase 1
Phosphorylation
Ribosomal Protein S6 Kinases
Anabolic Agents
Proteasome Endopeptidase Complex
tripterine
Cytoplasm
Skeletal Muscle
Up-Regulation
Gene Expression
Messenger RNA

All Science Journal Classification (ASJC) codes

  • Physiology
  • Pharmacology

Cite this

Gwag, T. ; Park, K. ; Park, Junsoo ; Lee, J. H. ; Nikawa, T. ; Choi, Inho. / Celastrol overcomes HSP72 gene silencing-mediated muscle atrophy and induces myofiber preservation. In: Journal of Physiology and Pharmacology. 2015 ; Vol. 66, No. 2. pp. 273-283.
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Celastrol overcomes HSP72 gene silencing-mediated muscle atrophy and induces myofiber preservation. / Gwag, T.; Park, K.; Park, Junsoo; Lee, J. H.; Nikawa, T.; Choi, Inho.

In: Journal of Physiology and Pharmacology, Vol. 66, No. 2, 01.01.2015, p. 273-283.

Research output: Contribution to journalArticle

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