Activities of Nonlysosomal Proteolytic Systems in Skeletal and Cardiac Muscle During Burn-Induced Hypermetabolism Journal Article

Authors: Wong, Y. M.; La Porte, H. M.; Szilagyi, A.; Bach, H. H., 4th; Ke-He, L.; Kennedy, R. H.; Gamelli, R. L.; Shankar, R.; Majetschak, M
Article Title: Activities of Nonlysosomal Proteolytic Systems in Skeletal and Cardiac Muscle During Burn-Induced Hypermetabolism
Abstract: The aim of this study was to assess the activity of nonlysosomal proteolytic systems in skeletal and cardiac muscle during burn-induced hypermetabolism (BHM) in rats. Rats underwent 30% TBSA scald burn or sham injury and were observed for up to 42 days. Body weights and resting energy expenditures were determined weekly. Skeletal (soleus/pectoral) muscle and hearts were harvested on days 0 (=control), 7, 14, 21, and 42 after burn. Calpain, caspase-1, caspase-3/7, caspase-6, caspase-8, caspase-9, and proteasome peptidase activities were measured in tissue extracts. Hypermetabolism developed within 3 weeks after burns, as documented by increased resting energy expenditures and decreased body weights on postburn days 21 to 42 (P 0.05 vs control). Calpain activities did not show significant alterations. Pan caspase activities increased by time and were significantly increased in skeletal and cardiac muscle extracts during hypermetabolism. Although increases in caspase-1, caspase-8, and caspase-9 activities were predominantly responsible for elevated pan caspase activities in skeletal muscle, increases in caspase-6 activities dominated in the heart. Proteasome peptidase activities in skeletal muscle extracts were not significantly altered. Proteasome peptidase activities in heart extracts increased time dependently and were significantly increased during BHM. Activation of caspase cascades during BHM constitutes a uniform response in skeletal and cardiac muscle and may contribute to enhanced metabolic protein turnover. Activation of myocardial proteasome activities may reflect persistent cardiac stress. Further exploration of caspase cascades and proteasome as therapeutic targets to influence long-term consequences of BHM seems justified.
Journal Title: Journal of burn care research : official publication of the American Burn Association
Volume: 35
Issue: 4
ISSN: 1559-0488; 1559-047X
Publisher: Unknown  
Date Published: 2014
Start Page: 319
End Page: 327
Language: ENG
Notes: LR: 20150701; GR: T32 GM008750/GM/NIGMS NIH HHS/United States; GR: T32GM008750/GM/NIGMS NIH HHS/United States; JID: 101262774; EC 3.4.22.- (Calpain); EC 3.4.22.- (Caspases); EC (Proteasome Endopeptidase Complex); NIHMS556228; OID: NLM: NIHMS556228; OID: NLM: PMC4397903; ppublish