Acute Heat Exposure Alters Autophagy Signaling in C2C12 Myotubes. 2019

Corey M Summers, and Rudy J Valentine
Department of Kinesiology, Iowa State University, Ames, IA, United States.

Autophagy is a major intracellular degradation process that is essential for the clearance of unnecessary proteins/organelles and the maintenance of cellular homeostasis. The inhibition of autophagy results in cellular consequences associated with many skeletal muscle pathologies, and therapies designed to elevate autophagic activity may provide protection from such pathologies. Acute exposure to low levels of heat has therapeutic effects; however, the impact of heat on skeletal muscle autophagy remains unclear. In the present study, C2C12 myotubes were maintained at 37°C thermoneutral (TN) or heated at 40°C heat treatment (HT) for 1 h. Myotubes were harvested immediately after heating, or returned to 37°C for recovery of 2 or 24 h. HT resulted in an elevation in pAMPK (T172), Beclin-1, and LC3 II, a marker for autophagosome formation, but no change in p62. In the context of autophagy inhibition with Bafilomycin A1, HT resulted in lower LC3 II compared to TN. The applied heat load induced the heat shock response, as evidenced by immediate upregulation of HSF1 and Hsp70. Hsp70 continued to increase during recovery, whereas pHsp27 was downregulated acutely in response to HT, but retuned to TN levels by 2 h of recovery. HT also reduced the phosphorylation of the MAP-kinases p38 and JNK. These findings suggest that an acute, short bout of mild heat may be beneficial to skeletal muscle by increasing AMPK activity, markers of autophagasome formation, and the heat shock response.

UI MeSH Term Description Entries

Related Publications

Corey M Summers, and Rudy J Valentine
February 2012, Journal of applied physiology (Bethesda, Md. : 1985),
Corey M Summers, and Rudy J Valentine
May 2017, Experimental cell research,
Corey M Summers, and Rudy J Valentine
June 2016, The Kobe journal of medical sciences,
Corey M Summers, and Rudy J Valentine
December 2005, Experimental biology and medicine (Maywood, N.J.),
Corey M Summers, and Rudy J Valentine
April 2017, Journal of muscle research and cell motility,
Corey M Summers, and Rudy J Valentine
January 2020, Journal of nutritional science and vitaminology,
Corey M Summers, and Rudy J Valentine
January 2014, Journal of nutrition and metabolism,
Corey M Summers, and Rudy J Valentine
September 2014, The international journal of biochemistry & cell biology,
Corey M Summers, and Rudy J Valentine
September 2014, Journal of biochemical and molecular toxicology,
Corey M Summers, and Rudy J Valentine
December 2016, Biochimica et biophysica acta,
Copied contents to your clipboard!