title: Overexpression of PGC-1α increases peroxisomal activity and mitochondrial fatty acid oxidation in human primary myotubes.
abstract: Peroxisomes are indispensable organelles for lipid metabolism in humans, and their biogenesis has been assumed to be under regulation by peroxisome proliferator-activated receptors (PPARs). However, recent studies in hepatocytes suggest that the mitochondrial proliferator PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1α) also acts as an upstream transcriptional regulator for enhancing peroxisomal abundance and associated activity. It is unknown whether the regulatory mechanism(s) for enhancing peroxisomal function is through the same node as mitochondrial biogenesis in human skeletal muscle (HSkM) and whether fatty acid oxidation (FAO) is affected. Primary myotubes from vastus lateralis biopsies from lean donors (BMI = 24.0 ± 0.6 kg/m2;n= 6) were exposed to adenovirus encoding human PGC-1α or GFP control. Peroxisomal biogenesis proteins (peroxins) and genes (PEXs) responsible for proliferation and functions were assessed by Western blotting and real-time qRT-PCR, respectively. [1-14C]palmitic acid and [1-14C]lignoceric acid (exclusive peroxisomal-specific substrate) were used to assess mitochondrial oxidation of peroxisomal-derived metabolites. After overexpression of PGC-1α,1) peroxisomal membrane protein 70 kDa (PMP70), PEX19, and mitochondrial citrate synthetase protein content were significantly elevated (P< 0.05),2)PGC-1α,PMP70, keyPEXs, and peroxisomal β-oxidation mRNA expression levels were significantly upregulated (P< 0.05), and3) a concomitant increase in lignoceric acid oxidation by both peroxisomal and mitochondrial activity was observed (P< 0.05). These novel findings demonstrate that, in addition to the proliferative effect on mitochondria, PGC-1α can induce peroxisomal activity and accompanying elevations in long-chain and very-long-chain fatty acid oxidation by a peroxisomal-mitochondrial functional cooperation, as observed in HSkM cells.
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina.
authors.forename: Tai-Yu
authors.initials: TY
authors.lastname: Huang
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina.|East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina.
authors.forename: Donghai
authors.initials: D
authors.lastname: Zheng
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Houmard
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina.|Department of Physiology, East Carolina University, Greenville, North Carolina.|Department of Biochemistry and Molecular Biology, East Carolina University, Greenville, North Carolina.|East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina.
authors.forename: Jeffrey J
authors.identifier: 0000-0003-3503-0528
authors.initials: JJ
authors.lastname: Brault
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina.|Department of Physiology, East Carolina University, Greenville, North Carolina.|East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina.|Center for Health Disparities, East Carolina University, Greenville, North Carolina; and.|Department of Biokinetics, Exercise, and Leisure Sciences, College of Health Sciences, University of KwaZulu-Natal, Westville, South Africa.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Hickner
authors.affiliation: Department of Kinesiology, East Carolina University, Greenville, North Carolina; cortrightr@ecu.edu.|Department of Physiology, East Carolina University, Greenville, North Carolina.|East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina.
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Cortright
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000328:Adult; D049109:Cell Proliferation; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D050356:Lipid Metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha / Q000235:genetics / Q000378:metabolism*; D020675:Peroxisomes / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000166:cytology / Q000378:metabolism*
chemical_list: C063305:ABCD3 protein, human; D018528:ATP-Binding Cassette Transporters; D005227:Fatty Acids; D008565:Membrane Proteins; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C087343:PEX19 protein, human
keywords: human skeletal muscle cells; lignoceric acid oxidation; obesity; peroxisome proliferator-activated receptors; β-oxidation