The independent effects of local heat application on muscle growth program associated mRNA and protein phosphorylation

• Published in: Journal of thermal biology 2023-07, Vol.115, p.103602, Article 103602
• Main Authors: McGlynn, Mark L., Rosales, Alejandro M., Collins, Christopher W., Slivka, Dustin R.
• Format: Article
• Language: English
• Subjects: 4E-BP1; Atrogin-1; Hot Temperature; Humans; mTOR; Muscle, Skeletal - metabolism; Myogenic; p70S6K1; Phosphorylation; Proteolytic; RNA, Messenger - metabolism; TOR Serine-Threonine Kinases - metabolism; TOR Serine-Threonine Kinases - pharmacology
• ISSN: 0306-4565
• DOI: 10.1016/j.jtherbio.2023.103602

The development and maintenance of skeletal muscle is crucial for the support of daily function. Recent evidence suggests that genes coded for proteins associated with the human muscle growth program (myogenic and proteolytic genes) are sensitive to local heat application. Therefore, the purpose of this investigation was to determine the effect of 4 h of local heat application to the vastus lateralis at rest on acute phosphorylation (mTORSer2448, p70-S6K1Thr389, and 4E-BP1Thr47/36) and gene expression changes for proteins associated with the muscle growth program. Intramuscular temperature of the HOT limb was 1.2 ± 0.2 °C higher than CON limb after 4 h of local heating. However, this local heat stimulus did not influence transcription of genes associated with myogenesis (MSTN, p = 0.321; MYF5, p = 0.445; MYF6, p = 0.895; MEF2a, p = 0.809; MYO-G, p = 0.766; MYO-D1, p = 0.118; RPS3, p = 0.321; and RPL-3L, p = 0.577), proteolysis (Atrogin-1, p = 0.573; FOXO3a, p = 0.452; MURF-1, p = 0.284), nor protein phosphorylation (mTORSer2448, p = 0.981; P70–S6K1Thr389, p = 0.583; 4E-BP1Thr37/46, p = 0.238) associated with the muscle growth program. These findings suggest little to no association between the local application of heat, at rest, and the activation of the observed muscle growth program-related markers. •After local heat application, Hot limb was 1.2 ± 0.2 °C greater than the Control limb.•Local heat application did not induce gene transcription differences between limbs.•Local heat application did not induce protein phosphorylation differences at rest.