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Suppression of plasma free fatty acids upregulates peroxisome proliferator-activated receptor (PPAR) alpha and delta and PPAR coactivator 1alpha in human skeletal muscle, but not lipid regulatory genes.
J Mol Endocrinol. 2004 Oct; 33(2):533-44.JM

Abstract

Fatty acids are an important ligand for peroxisome proliferator-activated receptor (PPAR) activation and transcriptional regulation of metabolic genes. To examine whether reduced plasma free fatty acid (FFA) availability affects the mRNA content of proteins involved in fuel metabolism in vivo, the skeletal muscle mRNA content of various transcription factors, transcriptional coactivators and genes encoding for lipid regulatory proteins were examined before and after 3 h of cycle exercise with (NA) and without (CON) pre-exercise ingestion of nicotinic acid (NA). NA resulted in a marked (3- to 6-fold) increase (P<0.05) in PPARalpha, PPARdelta and PPAR coactivator 1alpha (PGC1alpha) mRNA, but was without effect on nuclear respiratory factor-1 and Forkhead transcription factor, fatty acid transcolase/CD36, carnitine palmitoyl transferase 1, hormone sensitive lipase (HSL) and pyruvate dehydrogenase kinase 4. Exercise in CON was associated with increased (P<0.05) PPARalpha, PPARdelta and PGC1alpha mRNA, which was similar in magnitude to levels observed with NA at rest. Exercise was generally without effect on the mRNA content of lipid regulatory proteins in CON and did not affect the mRNA content of the measured subset of transcription factors, transcriptional co-activators and lipid regulatory proteins during NA. To determine the possible mechanisms by which NA might affect PGC1alpha expression, we measured p38 MAP kinase (MAPK) and plasma epinephrine. Phosphorylation of p38 MAPK was increased (P<0.05) by NA treatment at rest, and this correlated (r2=0.84, P<0.01) with increased PGC1alpha. Despite this close relationship, increasing p38 MAPK in human primary myotubes was without effect on PGC1alpha mRNA content. Plasma epinephrine was elevated (P<0.05) by NA at rest (CON: 0.27+/-0.06, NA: 0.72+/-0.11 nM) and throughout exercise. Incubating human primary myotubes with epinephrine increased PGC1alpha independently of changes in p38 MAPK phosphorylation. Hence, despite the fact that NA ingestion decreased FFA availability, it promoted the induction of PPARalpha/delta and PGC1alpha gene expression to a similar degree as prolonged exercise. We suggest that the increase in PGC1alpha may be due to the elevated plasma epinephrine levels. Despite these changes in transcription factors/coactivators, the mRNA content of lipid regulatory proteins was generally unaffected by plasma FFA availability.

Authors+Show Affiliations

Skeletal Muscle Research Laboratory, School of Medical Sciences, Royal Melbourne Institute of Technology, PO Box 27, Bundoora 3083, Victoria, Australia. matthew.watt@rmit.edu.auNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15525607

Citation

Watt, M J., et al. "Suppression of Plasma Free Fatty Acids Upregulates Peroxisome Proliferator-activated Receptor (PPAR) Alpha and Delta and PPAR Coactivator 1alpha in Human Skeletal Muscle, but Not Lipid Regulatory Genes." Journal of Molecular Endocrinology, vol. 33, no. 2, 2004, pp. 533-44.
Watt MJ, Southgate RJ, Holmes AG, et al. Suppression of plasma free fatty acids upregulates peroxisome proliferator-activated receptor (PPAR) alpha and delta and PPAR coactivator 1alpha in human skeletal muscle, but not lipid regulatory genes. J Mol Endocrinol. 2004;33(2):533-44.
Watt, M. J., Southgate, R. J., Holmes, A. G., & Febbraio, M. A. (2004). Suppression of plasma free fatty acids upregulates peroxisome proliferator-activated receptor (PPAR) alpha and delta and PPAR coactivator 1alpha in human skeletal muscle, but not lipid regulatory genes. Journal of Molecular Endocrinology, 33(2), 533-44.
Watt MJ, et al. Suppression of Plasma Free Fatty Acids Upregulates Peroxisome Proliferator-activated Receptor (PPAR) Alpha and Delta and PPAR Coactivator 1alpha in Human Skeletal Muscle, but Not Lipid Regulatory Genes. J Mol Endocrinol. 2004;33(2):533-44. PubMed PMID: 15525607.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Suppression of plasma free fatty acids upregulates peroxisome proliferator-activated receptor (PPAR) alpha and delta and PPAR coactivator 1alpha in human skeletal muscle, but not lipid regulatory genes. AU - Watt,M J, AU - Southgate,R J, AU - Holmes,A G, AU - Febbraio,M A, PY - 2004/11/5/pubmed PY - 2005/4/27/medline PY - 2004/11/5/entrez SP - 533 EP - 44 JF - Journal of molecular endocrinology JO - J. Mol. Endocrinol. VL - 33 IS - 2 N2 - Fatty acids are an important ligand for peroxisome proliferator-activated receptor (PPAR) activation and transcriptional regulation of metabolic genes. To examine whether reduced plasma free fatty acid (FFA) availability affects the mRNA content of proteins involved in fuel metabolism in vivo, the skeletal muscle mRNA content of various transcription factors, transcriptional coactivators and genes encoding for lipid regulatory proteins were examined before and after 3 h of cycle exercise with (NA) and without (CON) pre-exercise ingestion of nicotinic acid (NA). NA resulted in a marked (3- to 6-fold) increase (P<0.05) in PPARalpha, PPARdelta and PPAR coactivator 1alpha (PGC1alpha) mRNA, but was without effect on nuclear respiratory factor-1 and Forkhead transcription factor, fatty acid transcolase/CD36, carnitine palmitoyl transferase 1, hormone sensitive lipase (HSL) and pyruvate dehydrogenase kinase 4. Exercise in CON was associated with increased (P<0.05) PPARalpha, PPARdelta and PGC1alpha mRNA, which was similar in magnitude to levels observed with NA at rest. Exercise was generally without effect on the mRNA content of lipid regulatory proteins in CON and did not affect the mRNA content of the measured subset of transcription factors, transcriptional co-activators and lipid regulatory proteins during NA. To determine the possible mechanisms by which NA might affect PGC1alpha expression, we measured p38 MAP kinase (MAPK) and plasma epinephrine. Phosphorylation of p38 MAPK was increased (P<0.05) by NA treatment at rest, and this correlated (r2=0.84, P<0.01) with increased PGC1alpha. Despite this close relationship, increasing p38 MAPK in human primary myotubes was without effect on PGC1alpha mRNA content. Plasma epinephrine was elevated (P<0.05) by NA at rest (CON: 0.27+/-0.06, NA: 0.72+/-0.11 nM) and throughout exercise. Incubating human primary myotubes with epinephrine increased PGC1alpha independently of changes in p38 MAPK phosphorylation. Hence, despite the fact that NA ingestion decreased FFA availability, it promoted the induction of PPARalpha/delta and PGC1alpha gene expression to a similar degree as prolonged exercise. We suggest that the increase in PGC1alpha may be due to the elevated plasma epinephrine levels. Despite these changes in transcription factors/coactivators, the mRNA content of lipid regulatory proteins was generally unaffected by plasma FFA availability. SN - 0952-5041 UR - https://www.unboundmedicine.com/medline/citation/15525607/Suppression_of_plasma_free_fatty_acids_upregulates_peroxisome_proliferator_activated_receptor__PPAR__alpha_and_delta_and_PPAR_coactivator_1alpha_in_human_skeletal_muscle_but_not_lipid_regulatory_genes_ L2 - https://jme.bioscientifica.com/doi/10.1677/jme.1.01499 DB - PRIME DP - Unbound Medicine ER -