This study examines the impact of exercise intensity on the 12-hour time-course of mitochondrial biogenic gene and protein expression in human skeletal muscle. Briefly, participants will perform two experimental sessions involving an acute bout of work-matched low- or high-intensity interval cycling exercise in a randomized crossover fashion, two weeks apart. Skeletal muscle biopsies will be obtained from the vastus lateralis (3 from each leg) before and 1, 3, 6, 9, and 12 hours post-exercise. Changes in the expression of various transcription factors and mitochondrial proteins will be examined at the mRNA and protein level to determine the time-course of changes in these factors differs between exercise protocols of different intensities.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
10
Participants will perform an acute bout of low-intensity cycling (11 x 1 min intervals at \~73% of peak aerobic work rate interspersed with 1 min recovery periods)
Participants will perform an acute bout of high-intensity cycling (8 x 1 min intervals at \~100% of peak aerobic work rate interspersed with 1 min recovery periods)
School of Kinesiology and Health Studies
Kingston, Ontario, Canada
RECRUITINGChange in peroxisome proliferator activated receptor (PPAR) gamma co-activator 1-alpha (PGC-1α) messenger ribonucleic acid (mRNA) expression
PGC-1α gene expression (indirect indicator of PGC-1α activity). Transcriptional co-activator involved in the control of mitochondrial biogenesis.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in PGC-1α protein content
PGC-1α protein content
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in nuclear factor-erythroid 2 like 2 (Nrf2) mRNA expression
Nrf2 gene expression (indirect indicator of Nrf2 activity). Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in Nrf2 protein content
Nrf2 protein content
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in PPAR-beta mRNA expression
PPAR-beta gene expression (indirect indicator of PPAR-beta activity). Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in estrogen related receptor (ERR)-gamma mRNA expression
ERR-gamma gene expression. Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in leucine-rich pentatricopeptide repeat containing protein 130 (LRP130) mRNA expression
LRP130 gene expression. Transcriptional co-activator and RNA-binding protein involved in the transcriptional control and stabilization of mitochondrial mRNAs
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in LRP130 protein content
LRP130 protein content
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in nuclear respiratory factor-1 (NRF-1) mRNA expression
NRF-1 gene expression. Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in NRF-1 protein content
NRF-1 protein content
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in mitochondrial transcription factor A (TFAM) mRNA expression
TFAM gene expression. Transcription factor controlling the expression of mitochondrial-encoded genes.
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in TFAM protein content
TFAM protein content
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in p53 mRNA expression
p53 gene expression. Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in cytochrome c oxidase subunit 4 (COXIV) mRNA expression.
COXIV gene expression. Nuclear encoded subunit of the electron transport chain complex 4 (COX)
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in COXI mRNA expression
COXI gene expression. Mitochondrial encoded subunit of the electron transport chain complex IV (COX)
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in COXII mRNA expression
COXII gene expression.Mitochondrial encoded subunit of the electron transport chain complex IV (COX).
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in nicotinamide adenine dinucleotide (NADH) subunit 1 (ND1) mRNA expression
ND1 gene expression. Mitochondrial encoded subunit of the electron transport chain complex 1 (NADH dehydrogenase)
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in ND4 mRNA expression
ND4 gene expression. Mitochondrial encoded subunit of the electron transport chain complex 1 (NADH dehydrogenase).
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in citrate synthase (CS) mRNA expression
CS gene expression. The first rate limiting enzyme of the Kreb's cycle.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in NRF-2 mRNA expression
NRF-2 gene expression. Transcription factor involved in the control of mitochondrial biogenesis.
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
Change in mitochondrial transcription factor B1 (TFB1M) mRNA expression
TFB1M gene expression. Transcription factor controlling the expression of mitochondrial-encoded genes.
Time frame: before exercise to 1, 3, 6, 9, and 12 hours post-exercise
Change in mitochondrial transcription factor B2 (TFB2M) mRNA expression
TFB2M gene expression. Transcription factor controlling the expression of mitochondrial-encoded genes.
Time frame: before exercise and 1, 3, 6, 9, and 12 hours post-exercise
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