Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice

Author(s)

Cunha, Telma F. ; Moreira, Jose B. N. ; Paixao, Nathalie A. ; Campos, Juliane C. ; Monteiro, Alex W. A. ; Bacurau, Aline V. N. ; Bueno, Jr., Carlos R. ^[1] ; Ferreira, Julio C. B. ^[2] ; Brum, Patricia C. ^[3]

Affiliation

^[1] Univ Sao Paulo, Human Genome Res Ctr, BR-05508900 Sao Paulo - Brazil

^[2] Stanford Univ, Sch Med, Dept Chem & Syst Biol, Stanford, CA 94305 - USA

^[3] Univ Sao Paulo, Escola Educ Fis & Esporte, Dept Biodinam Movimento Corpo Humano, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Applied Physiology; v. 112, n. 11, p. 1839-1846, JUN 2012.
• Web of Science Citations: 24

Abstract

Cunha TF, Moreira JB, Paixao NA, Campos JC, Monteiro AW, Bacurau AV, Bueno CR Jr., Ferreira JC, Brum PC. Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice. J Appl Physiol 112: 1839-1846, 2012. First published March 29, 2012; doi:10.1152/japplphysiol.00346.2011.-Aerobic exercise training (AET) is an important mechanical stimulus that modulates skeletal muscle protein turnover, leading to structural rearrangement. Since the ubiquitin-proteasome system (UPS) and calpain system are major proteolytic pathways involved in protein turnover, we aimed to investigate the effects of intensity-controlled AET on the skeletal muscle UPS and calpain system and their association to training-induced structural adaptations. Long-lasting effects of AET were studied in C57BL/6J mice after 2 or 8 wk of AET. Plantaris cross-sectional area (CSA) and capillarization were assessed by myosin ATPase staining. mRNA and protein expression levels of main components of the UPS and calpain system were evaluated in plantaris by real-time PCR and Western immunoblotting, respectively. No proteolytic system activation was observed after 2 wk of AET. Eight weeks of AET resulted in improved running capacity, plantaris capillarization, and CSA. Muscle RING finger-1 mRNA expression was increased in 8-wk-trained mice. Accordingly, elevated 26S proteasome activity was observed in the 8-wk-trained group, without accumulation of ubiquitinated or carbonylated proteins. In addition, calpain abundance was increased by 8 wk of AET, whereas no difference was observed in its endogenous inhibitor calpastatin. Taken together, our findings indicate that skeletal muscle enhancements, as evidenced by increased running capacity, plantaris capillarization, and CSA, occurred in spite of the upregulated UPS and calpain system, suggesting that overactivation of skeletal muscle proteolytic systems is not restricted to atrophying states. Our data provide evidence for the contribution of the UPS and calpain system to metabolic turnover of myofibrillar proteins and skeletal muscle adaptations to AET. (AU)

• FAPESP's process: 06/56321-6 - Involvement of protein kinase C βII and ε isoforms in heart failure induced by myocardial infarction
• Grantee: Julio Cesar Batista Ferreira
• Support type: Scholarships in Brazil - Doctorate