Effect of temperature on fatty acid metabolism in skeletal muscle mitochondria of untrained and endurance-trained rats
PLOS ONE
Authors: Zoladz, Jerzy A.; Koziel, Agnieszka; Broniarek, Izabela; Woyda-Ploszczyca, Andrzej M.; Ogrodna, Karolina; Majerczak, Joanna; Celichowski, Jan; Szkutnik, Zbigniew; Jarmuszkiewicz, Wieslawa
Abstract
We studied the effects of various assay temperatures, representing hypothermia (25 degrees C), normothermia (35 degrees C), and hyperthermia (42 degrees C), on the oxidation of lipid-derived fuels in rat skeletal muscle mitochondria of untrained and endurance-trained rats. Adult 4-month-old male Wistar rats were assigned to a training group (rats trained on a treadmill for 8 weeks) or a sedentary control group. In skeletal muscle mitochondria of both control and trained rats, an increase in the assay temperature from 25 degrees C to 42 degrees C was accompanied by a consistent increase in the oxidation of palmitoylcarnitine and glycerol-3-phosphate. Moreover, endurance training increased mitochondrial capacity to oxidize the lipid-derived fuels at all studied temperatures. The endurance training-induced increase in mitochondrial capacity to oxidize fatty acids was accompanied by an enhancement of mitochondrial biogenesis, as shown by the elevated expression levels of Nrf2, PGC1 alpha, and mitochondrial marker and by the elevated expression levels of mitochondrial proteins involved in fatty acid metabolism, such as fatty acid transporter CD36, carnitine palmitoyltransferase 1A (CPT1A), and acyl-CoA dehydrogenase (ACADS). We conclude that hyperthermia enhances but hypothermia attenuates the rate of the oxidation of fatty acids and glycerol-3-phosphate in rat skeletal muscle mitochondria isolated from both untrained and trained rats. Moreover, our results indicate that endurance training up-regulates mitochondrial biogenesis markers, lipid-sustained oxidative capacity, and CD36 and CPT1A proteins involved in fatty acid transport, possibly via PGC1 alpha and Nrf2 signaling pathways.
Deficiency in short-chain fatty acid beta-oxidation affects theta oscillations during sleep
NATURE GENETICS
Authors: Tafti, M; Petit, B; Chollet, D; Neidhart, E; de Bilbao, F; Kiss, JZ; Wood, PA; Franken, P
Abstract
In rodents, the electroencephalogram (EEG) during paradoxical sleep and exploratory behavior is characterized by theta oscillations. Here we show that a deficiency in short-chain acylcoenzyme A dehydrogenase (encoded by Acads) in mice causes a marked slowing in theta frequency during paradoxical sleep only. We found Acads expression in brain regions involved in theta generation, notably the hippocampus. Microarray analysis of gene expression in mice with mutations in Acads indicates overexpression of Glo1 (encoding glyoxylase 1), a gene involved in the detoxification of metabolic by-products. Administration of acetyl-L-carnitine (ALCAR) to mutant mice significantly recovers slow theta and Glo1 overexpression. Thus, an underappreciated metabolic pathway involving fatty acid beta-oxidation also regulates theta oscillations during sleep.