title: Translational machinery of mitochondrial mRNA is promoted by physical activity in Western diet-induced obese mice.
abstract: Mitochondria-encoded proteins are necessary for oxidative phosphorylation; however, no report has examined how physical activity (PA) and obesity affect mitochondrial mRNA translation machinery. Our purpose was to determine whether Western diet (WD)-induced obesity and voluntary wheel running (VWR) impact mitochondrial mRNA translation machinery and whether expression of this machinery is dictated by oxidative phenotype.
  
  
  
  Obesity was induced with 8-wk WD feeding, and in the final 4 wks, half of mice were allowed VWR. Mitochondrial mRNA translation machinery including initiation factors (mtIF2/3), elongation factor Tu (TUFM) and translational activator (TACO1), and mitochondria-encoded proteins (CytB and ND4) was assessed by immunoblotting. The relation of mitochondrial mRNA translation to muscle oxidative phenotype was assessed using PGC-1α transgenic overexpression (MCK-PGC-1α vs. wild-type mice) and comparing across muscle groups in wild-type mice.
  
  
  
  mtIF3 and TACO1 proteins were ~45% greater in VWR than sedentary (SED), and TACO1 and mtIF2 proteins were ~60% and 125% greater in WD than normal chow (NC). TUFM protein was ~50% lower in WD-SED than NC-SED, but ~50% greater in WD-VWR compared to NC-SED. CytB and ND4 were ~40% greater in VWR and ND4 was twofold greater with WD. TUFM, TACO1, ND4 and CytB were greater in MCK-PGC-1α compared to wild-type, and mtIF2/3 contents were not different. In oxidative muscle (soleus), mitochondrial translation machinery was elevated compared to mixed (gastrocnemius) or glycolytic (extensor digitorum longus) muscles.
  
  
  
  These data suggest a novel mechanism promoting mitochondrial function by translation of mitochondrial protein following PA. This may act to promote muscle health by PA in obesity.
authors.affiliation: Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Lee
authors.affiliation: Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Brown
authors.affiliation: Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Rosa
authors.affiliation: Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Brown
authors.affiliation: Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Perry
authors.affiliation: Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Washington
authors.affiliation: Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA. npgreene@uark.edu.
authors.forename: N P
authors.initials: NP
authors.lastname: Greene
mesh_terms: D000818:Animals; D045303:Cytochromes b / Q000235:genetics / Q000378:metabolism; D066273:Diet, Western; D005786:Gene Expression Regulation; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010444:Peptide Elongation Factor Tu / Q000235:genetics / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
chemical_list: D008840:Microfilament Proteins; D012333:RNA, Messenger; C072061:coronin proteins; D045303:Cytochromes b; D010444:Peptide Elongation Factor Tu
keywords: PGC-1α; TACO1; TUFM; exercise and obesity; mtIFs