We read with interest the recent article by Toledo et al. . In their study, the authors found that mRNA levels for SIRT1 were increased in muscle from tumor-bearing rats and that SIRT3 mRNA levels were unchanged. In the discussion of the results, the authors stated that the observation of unchanged SIRT3 “is in contrast with that of Alamdari et al.  showing an upregulation of SIRT3 in skeletal muscle during sepsis”. This was a surprising statement since we did not examine or report on SIRT3 expression in our study . We did examine the effects of sepsis on the mRNA levels for the histone deacetylases HDAC3 and 6 and nuclear protein levels for the same HDACs as well as for SIRT1. Importantly, protein levels for HDAC6 and SIRT1 were decreased (not increased) and muscle HDAC activity was reduced during sepsis.
We think the misquotation of our work in the article by Toledo et al.  was unfortunate, not only because it was erroneous but also because it suggests that the expression of a histone deacetylase (SIRT3) may be increased during sepsis, implying increased deacetylase activity and reduced levels of acetylated cellular proteins. This is opposite to the conclusions in our paper  and in other recent reports from our laboratory [3–7] in which we found evidence that muscle wasting caused by sepsis and glucocorticoids is associated with, and probably at least in part regulated by increased acetylation of cellular proteins. These conclusions were also supported by experiments in which treatment of cultured muscle cells  or rats in vivo  with histone deacetylase inhibitor increased the expression of atrogin-1 and stimulated protein breakdown. In more recent experiments, we found evidence for a role of reduced (not increased) SIRT1 expression and activity in glucocorticoid-induced muscle wasting . It was surprising to see that SIRT1 mRNA levels were increased in muscle from tumor-bearing rats in the study by Toledo et al. . It would have been interesting to have information about SIRT1 protein levels and HDAC activity in the same muscles.
|1.||Toledo M, Busquets S, Ametller E, Lopez-Soriano FJ, Argiles JM. Sirtuin 1 in skeletal muscle of cachectic tumour-bearing rats:
a role in impaired regeneration? J Cachexia Sarcopenia Muscle. 2011;2:57–62.
|2.||Alamdari N, Smith IJ, Aversa Z, Hasselgren PO. Sepsis and glucocorticoids upregulate p300 and downregulate HDAC6 expression
and activity in skeletal muscle. Am J Physiol Regul Integr Comp Physiol. 2010;299:R509–20.
|3.||Yang H, Menconi MJ, Wei W, Petkova V, Hasselgren PO. Dexamethasone upregulates the expression of the nuclear cofactor p300
and its interaction with C/EBPbeta in cultured myotubes. J Cell Biochem. 2005;94:1058–67.
|4.||Yang H, Wei W, Menconi M, Hasselgren PO. Dexamethasone-induced protein degradation in cultured myotubes is p300/HAT dependent.
Am J Physiol Integr Comp Physiol. 2007;292:R337–44.
|5.||Hasselgren PO. Ubiquitination,
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|6.||Chamberlain W, Gonnella P, Alamdari N, Aversa Z, Hasselgren PO. Multiple muscle wasting-related transcription factors are acetylated in dexamethasone-treated muscle cells. Biochem Cell Biol. 2012. doi:10.1139/o11-082|
|7.||Alamdari N, Aversa Z, Castillero
E, Gurav A, Petkova V, Tizio S, Hasselgren PO. Resveratrol prevents
expression of the muscle atrophy-related ubiquitin
ligases atrogin-1 and MuRF1 in cultured myotubes through a
mechanism. Biochem Biophys Res Commun.
|8.||von Haehling S, Morley JE, Coats AJS, Anker SD. Ethical guidelines for authorship and publishing in the Journal of Cachexia, Sarcopenia and Muscle. J Cachexia Sarcopenia Muscle. 2010;1:7–8|