title: Response of mitochondrial fusion and fission protein gene expression to exercise in rat skeletal muscle.
abstract: The purpose of this study was to investigate the changes in the gene expression of Mitofusion (Mfn) 1 and 2 and Fission 1 (Fis1) and mitochondrial energy metabolism in response to altered energy demand during prolonged exercise in rat skeletal muscle. Male Sprague-Dawley rats were subjected to an acute bout of treadmill running at various durations and killed immediately or during recovery. Mfn1/2 and Fis1 mRNA and protein contents, reactive oxygen species (ROS) generation, state 3 and state 4 respiration rates, trans-innermembrane potential and ATP synthase activity were measured in isolated muscle mitochondria. We found that (1) Mfn1/2 mRNA contents were progressively decreased during 150 min of exercise, along with decreased Mfn 1 protein levels. Fis1 mRNA and protein contents showed significant increases after 120-150 min of exercise. These changes persisted through the recovery period up to 24 h. (2) Mitochondrial ROS generation and state 4 respiration showed progressive increases up to 120 min, but dropped at 150 min of exercise. (3) State 3 respiration rate and respiratory control index were unchanged initially but decreased at 150 and 120 min of exercise, respectively, whereas ATP synthase activity was elevated at 45 min and returned to resting level thereafter. Our data suggested that the gene expression of mitochondrial fusion and fission proteins in skeletal muscle can respond rapidly to increased metabolic demand during prolonged exercise, which could significantly affect the efficiency of oxidative phosphorylation.
authors.affiliation: Tianjin Key Laboratory of Exercise Physiology and Sports Medicine; Department of Health & Exercise Science, Tianjin University of Sport, Tianjin 300381, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Ding
authors.forename: Ning
authors.initials: N
authors.lastname: Jiang
authors.forename: Huijun
authors.initials: H
authors.lastname: Liu
authors.forename: Xiaoran
authors.initials: X
authors.lastname: Liu
authors.forename: Danxia
authors.initials: D
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Wen
authors.forename: Shusen
authors.initials: S
authors.lastname: Liu
authors.forename: Li Li
authors.initials: LL
authors.lastname: Ji
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017931:DNA Primers; D004734:Energy Metabolism; D020558:GTP Phosphohydrolases; D005784:Gene Amplification; D005786:Gene Expression Regulation; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008931:Mitochondria, Muscle / Q000235:genetics / Q000502:physiology*; D024101:Mitochondrial Proteins / Q000235:genetics; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012146:Rest / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; C503403:Fis1 protein, rat; D008565:Membrane Proteins; C489709:Mfn1 protein, rat; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D020558:GTP Phosphohydrolases; C489710:Mfn2 protein, rat