The orphan nuclear receptor, NOR-1, a target of beta-adrenergic signaling, regulates gene expression that controls oxidative metabolism in skeletal muscle

Endocrinology. 2008 Jun;149(6):2853-65. doi: 10.1210/en.2007-1202. Epub 2008 Mar 6.

Abstract

beta 1-3-Adrenoreceptor (AR)-deficient mice are unable to regulate energy expenditure and develop diet-induced obesity on a high-fat diet. We determined previously that beta2-AR agonist treatment activated expression of the mRNA encoding the orphan nuclear receptor, NOR-1, in muscle cells and plantaris muscle. Here we show that beta2-AR agonist treatment significantly and transiently activated the expression of NOR-1 (and the other members of the NR4A subgroup) in slow-twitch oxidative soleus muscle and fast-twitch glycolytic tibialis anterior muscle. The activation induced by beta-adrenergic signaling is consistent with the involvement of protein kinase A, MAPK, and phosphorylation of cAMP response element-binding protein. Stable cell lines transfected with a silent interfering RNA targeting NOR-1 displayed decreased palmitate oxidation and lactate accumulation. In concordance with these observations, ATP production in the NOR-1 silent interfering RNA (but not control)-transfected cells was resistant to (azide-mediated) inhibition of oxidative metabolism and expressed significantly higher levels of hypoxia inducible factor-1alpha. In addition, we observed the repression of genes that promote fatty acid oxidation (peroxisomal proliferator-activated receptor-gamma coactivator-1alpha/beta and lipin-1alpha) and trichloroacetic acid cycle-mediated carbohydrate (pyruvate) oxidation [pyruvate dehydrogenase phosphatase 1 regulatory and catalytic subunits (pyruvate dehydrogenase phosphatases-1r and -c)]. Furthermore, we observed that beta2-AR agonist administration in mouse skeletal muscle induced the expression of genes that activate fatty acid oxidation and modulate pyruvate use, including PGC-1alpha, lipin-1alpha, FOXO1, and PDK4. Finally, we demonstrate that NOR-1 is recruited to the lipin-1alpha and PDK-4 promoters, and this is consistent with NOR-1-mediated regulation of these genes. In conclusion, NOR-1 is necessary for oxidative metabolism in skeletal muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Agonists / pharmacology
  • Animals
  • Cell Line
  • DNA-Binding Proteins / genetics*
  • Ethanolamines / pharmacology
  • Formoterol Fumarate
  • Mice
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Nerve Tissue Proteins / genetics*
  • Oxidation-Reduction
  • Oxygen Consumption
  • Palmitic Acid / metabolism
  • Plasmids
  • RNA, Messenger / genetics
  • Receptors, Steroid / genetics*
  • Receptors, Thyroid Hormone / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Transfection

Substances

  • Adrenergic beta-Agonists
  • DNA-Binding Proteins
  • Ethanolamines
  • Nerve Tissue Proteins
  • Nr4a3 protein, mouse
  • RNA, Messenger
  • Receptors, Steroid
  • Receptors, Thyroid Hormone
  • Palmitic Acid
  • Formoterol Fumarate