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Deficiency of heat shock transcription factor 1 suppresses heat stress‐associated increase in slow soleus muscle mass of mice
Author(s) -
Ohno Y.,
Egawa T.,
Yokoyama S.,
Nakai A.,
Sugiura T.,
Ohira Y.,
Yoshioka T.,
Goto K.
Publication year - 2015
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12600
Subject(s) - soleus muscle , heat shock protein , hsp70 , medicine , endocrinology , heat shock , skeletal muscle , protein kinase b , biology , chemistry , phosphorylation , microbiology and biotechnology , biochemistry , gene
Aim Effects of heat shock transcription factor 1 ( HSF 1) deficiency on heat stress‐associated increase in slow soleus muscle mass of mice were investigated. Methods Both HSF 1‐null and wild‐type mice were randomly assigned to control and heat‐stressed groups. Mice in heat‐stressed group were exposed to heat stress (41 °C for 60 min) in an incubator without anaesthesia. Results Significant increase in wet and dry weights, and protein content of soleus muscle in wild‐type mice was observed seven days after the application of the heat stress. However, heat stress had no impact on soleus muscle mass in HSF 1‐null mice. Neither type of mice exhibited much effect of heat stress on HSF mRNA expression ( HSF 1, HSF 2 and HSF 4). On the other hand, heat stress upregulated heat shock proteins ( HSP s) at the mRNA ( HSP 72) and protein ( HSP 72 and HSP 110) levels in wild‐type mice, but not in HSF 1‐null mice. The population of Pax7‐positive nuclei relative to total myonuclei of soleus muscle in wild‐type mice was significantly increased by heat stress, but not in HSF 1‐null mice. Furthermore, the absence of HSF 1 gene suppressed heat stress‐associated phosphorylation of Akt and p70 S6 kinase (p‐p70S6K) in soleus muscle. Conclusion Heat stress‐associated increase in skeletal muscle mass may be induced by HSF 1 and/or HSF 1‐mediated stress response that activates muscle satellite cells and Akt/p70S6K signalling pathway.