Time course and fibre type-dependent nature of calcium-handling protein responses to sprint interval exercise in human skeletal muscle.

Autor: Tripp TR; Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada., Frankish BP; Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.; Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia., Lun V; University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada., Wiley JP; Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.; University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada., Shearer J; Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.; Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada., Murphy RM; Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia., MacInnis MJ; Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
Jazyk: angličtina
Zdroj: The Journal of physiology [J Physiol] 2022 Jun; Vol. 600 (12), pp. 2897-2917. Date of Electronic Publication: 2022 May 29.
DOI: 10.1113/JP282739
Abstrakt: Sprint interval training (SIT) causes fragmentation of the skeletal muscle sarcoplasmic reticulum Ca 2+ release channel, ryanodine receptor 1 (RyR1), 24 h post-exercise, potentially signalling mitochondrial biogenesis by increasing cytosolic [Ca 2+ ]. Yet, the time course and skeletal muscle fibre type-specific patterns of RyR1 fragmentation following a session of SIT remain unknown. Ten participants (n = 4 females; n = 6 males) performed a session of SIT (6 × 30 s 'all-out' with 4.5 min rest after each sprint) with vastus lateralis muscle biopsy samples collected before and 3, 6 and 24 h after exercise. In whole muscle, full-length RyR1 protein content was significantly reduced 6 h (mean (SD); -38 (38)%; P < 0.05) and 24 h post-SIT (-30 (48)%; P < 0.05) compared to pre-exercise. Examining each participant's largest response in pooled samples, full-length RyR1 protein content was reduced in type II (-26 (30)%; P < 0.05) but not type I fibres (-11 (40)%; P > 0.05). Three hours post-SIT, there was also a decrease in sarco(endo)plasmic reticulum Ca 2+ ATPase 1 in type II fibres (-23 (17)%; P < 0.05) and sarco(endo)plasmic reticulum Ca 2+ ATPase 2a in type I fibres (-19 (21)%; P < 0.05), despite no time effect for either protein in whole muscle samples (P > 0.05). PGC1A mRNA content was elevated 3 and 6 h post-SIT (5.3- and 3.7-fold change from pre, respectively; P < 0.05 for both), but peak PGC1A mRNA expression was not significantly correlated with peak RyR1 fragmentation (r 2  = 0.10; P > 0.05). In summary, altered Ca 2+ -handling protein expression, which occurs primarily in type II muscle fibres, may influence signals for mitochondrial biogenesis as early as 3-6 h post-SIT in humans. KEY POINTS: Sprint interval training (SIT) has been shown to cause fragmentation of the sarcoplasmic reticulum calcium-release channel, ryanodine receptor 1 (RyR1), 24 h post-exercise, which may act as a signal for mitochondrial biogenesis. In this study, the time course was examined of RyR1 fragmentation in human whole muscle and pooled type I and type II skeletal muscle fibres following a single session of SIT. Full-length RyR1 protein content was significantly lower than pre-exercise by 6 h post-SIT in whole muscle, and fragmentation was detectable in type II but not type I fibres, though to a lesser extent than in whole muscle. The peak in PGC1A mRNA expression occurred earlier than RyR1 fragmentation. The increased temporal resolution and fibre type-specific responses for RyR1 fragmentation provide insights into its importance to mitochondrial biogenesis in humans.
(© 2022 The Authors. The Journal of Physiology © 2022 The Physiological Society.)
Databáze: MEDLINE
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