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Metabolomic Analysis of the Skeletal Muscle of Mice Overexpressing PGC-1α.

Hatazawa Y, Senoo N, Tadaishi M, Ogawa Y, Ezaki O, Kamei Y, Miura S - PLoS ONE (2015)

Bottom Line: Meanwhile, BCAA levels decreased (Val, 0.7-fold; Leu, 0.8-fold; and Ile, 0.7-fold), and Glu (3.1-fold) and Asp (2.2-fold) levels increased.Moreover, our metabolomics data showing the activation of the purine nucleotide pathway, malate-aspartate shuttle, as well as creatine metabolism, which are known to be active during exercise, further suggests that PGC-1α regulates metabolism in exercise.Thus, we demonstrated the roles of PGC-1α in the skeletal muscle at the metabolite level.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan.

ABSTRACT
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α) is a coactivator of various nuclear receptors and other transcription factors whose expression increases in the skeletal muscle during exercise. We have previously made transgenic mice overexpressing PGC-1α in the skeletal muscle (PGC-1α-Tg mice). PGC-1α upregulates the expression of genes associated with red fibers, mitochondrial function, fatty acid oxidation, and branched chain amino acid (BCAA) degradation. However, global analyses of the actual metabolic products have not been investigated. In this study, we conducted metabolomic analysis of the skeletal muscle in PGC-1α-Tg mice by capillary electrophoresis with electrospray ionization time-of-flight mass spectrometry. Principal component analysis and hierarchical cluster analysis showed clearly distinguishable changes in the metabolites between PGC-1α-Tg and wild-type control mice. Changes were observed in metabolite levels of various metabolic pathways such as the TCA cycle, pentose phosphate pathway, nucleotide synthesis, purine nucleotide cycle, and amino acid metabolism, including BCAA and β-alanine. Namely, metabolic products of the TCA cycle increased in PGC-1α-Tg mice, with increased levels of citrate (2.3-fold), succinate (2.2-fold), fumarate (2.8-fold), and malate (2.3-fold) observed. Metabolic products associated with the pentose phosphate pathway and nucleotide biosynthesis also increased in PGC-1α-Tg mice. Meanwhile, BCAA levels decreased (Val, 0.7-fold; Leu, 0.8-fold; and Ile, 0.7-fold), and Glu (3.1-fold) and Asp (2.2-fold) levels increased. Levels of β-alanine and related metabolites were markedly decreased in PGC-1α-Tg mice. Coordinated regulation of the TCA cycle and amino acid metabolism, including BCAA, suggests that PGC-1α plays important roles in energy metabolism. Moreover, our metabolomics data showing the activation of the purine nucleotide pathway, malate-aspartate shuttle, as well as creatine metabolism, which are known to be active during exercise, further suggests that PGC-1α regulates metabolism in exercise. Thus, we demonstrated the roles of PGC-1α in the skeletal muscle at the metabolite level.

No MeSH data available.


Related in: MedlinePlus

Observed metabolite changes mapped onto the pathways involved in nucleotide synthesis.Changes in the metabolite levels in the skeletal muscle of PGC-1α-Tg mice and WT mice are shown. Relative metabolite changes shown in the graphs were obtained by CE-TOFMS (S1 Table). Open bars, WT and filled bars, PGC-1α-Tg (N = 3). Data are expressed as the mean ± SD. Asterisks indicate statistically significant differences (**p < 0.01, *p < 0.05).
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pone.0129084.g005: Observed metabolite changes mapped onto the pathways involved in nucleotide synthesis.Changes in the metabolite levels in the skeletal muscle of PGC-1α-Tg mice and WT mice are shown. Relative metabolite changes shown in the graphs were obtained by CE-TOFMS (S1 Table). Open bars, WT and filled bars, PGC-1α-Tg (N = 3). Data are expressed as the mean ± SD. Asterisks indicate statistically significant differences (**p < 0.01, *p < 0.05).

Mentions: Ribose 5-phosphate, derived from the pentose phosphate pathway, is a starting material for nucleotide biosynthesis, including pyrimidines and purines [9, 10]. We observed a change in metabolite levels of these pathways. For pyrimidine biosynthesis, ribose 5-phosphate (2.4-fold) is metabolized to 5-phosphoribosyl pyrophosphate (PRPP) (0.5-fold), uridine monophosphate (UMP) (detected only in PGC-1α-Tg mice, but not in WT mice), uridine diphosphate (UDP) (detected only in PGC-1α-Tg mice, but not in WT mice), uridine triphosphate (UTP) (1.0-fold), and cytidine triphosphate (CTP) (0.7-fold) (Fig 5 and S1 Table). For purine biosynthesis, ribose 5-phosphate (2.4-fold) is metabolized to inosine monophosphate (IMP) (5.4-fold), which is used in the purine nucleotide cycle (described in the next paragraph). IMP is metabolized to AMP (detected only in PGC-1α-Tg mice, but not in WT control mice), ADP (3.4-fold), and ATP (0.7-fold). IMP is also metabolized to GMP (16-fold), GDP (detected only in PGC-1α-Tg mice, but not in WT mice), and GTP (1.3-fold) (Fig 5 and S1 Table). Among them, UTP, CTP, ATP, and GTP may be used for RNA synthesis, which is consistent with the previous report that RNA synthesis is stimulated in PGC-1α-Tg mice [11]. Because many of the associated metabolites are increased, the nucleotide biosynthesis pathway appears to be activated in PGC-1α-Tg mice.


Metabolomic Analysis of the Skeletal Muscle of Mice Overexpressing PGC-1α.

Hatazawa Y, Senoo N, Tadaishi M, Ogawa Y, Ezaki O, Kamei Y, Miura S - PLoS ONE (2015)

Observed metabolite changes mapped onto the pathways involved in nucleotide synthesis.Changes in the metabolite levels in the skeletal muscle of PGC-1α-Tg mice and WT mice are shown. Relative metabolite changes shown in the graphs were obtained by CE-TOFMS (S1 Table). Open bars, WT and filled bars, PGC-1α-Tg (N = 3). Data are expressed as the mean ± SD. Asterisks indicate statistically significant differences (**p < 0.01, *p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482640&req=5

pone.0129084.g005: Observed metabolite changes mapped onto the pathways involved in nucleotide synthesis.Changes in the metabolite levels in the skeletal muscle of PGC-1α-Tg mice and WT mice are shown. Relative metabolite changes shown in the graphs were obtained by CE-TOFMS (S1 Table). Open bars, WT and filled bars, PGC-1α-Tg (N = 3). Data are expressed as the mean ± SD. Asterisks indicate statistically significant differences (**p < 0.01, *p < 0.05).
Mentions: Ribose 5-phosphate, derived from the pentose phosphate pathway, is a starting material for nucleotide biosynthesis, including pyrimidines and purines [9, 10]. We observed a change in metabolite levels of these pathways. For pyrimidine biosynthesis, ribose 5-phosphate (2.4-fold) is metabolized to 5-phosphoribosyl pyrophosphate (PRPP) (0.5-fold), uridine monophosphate (UMP) (detected only in PGC-1α-Tg mice, but not in WT mice), uridine diphosphate (UDP) (detected only in PGC-1α-Tg mice, but not in WT mice), uridine triphosphate (UTP) (1.0-fold), and cytidine triphosphate (CTP) (0.7-fold) (Fig 5 and S1 Table). For purine biosynthesis, ribose 5-phosphate (2.4-fold) is metabolized to inosine monophosphate (IMP) (5.4-fold), which is used in the purine nucleotide cycle (described in the next paragraph). IMP is metabolized to AMP (detected only in PGC-1α-Tg mice, but not in WT control mice), ADP (3.4-fold), and ATP (0.7-fold). IMP is also metabolized to GMP (16-fold), GDP (detected only in PGC-1α-Tg mice, but not in WT mice), and GTP (1.3-fold) (Fig 5 and S1 Table). Among them, UTP, CTP, ATP, and GTP may be used for RNA synthesis, which is consistent with the previous report that RNA synthesis is stimulated in PGC-1α-Tg mice [11]. Because many of the associated metabolites are increased, the nucleotide biosynthesis pathway appears to be activated in PGC-1α-Tg mice.

Bottom Line: Meanwhile, BCAA levels decreased (Val, 0.7-fold; Leu, 0.8-fold; and Ile, 0.7-fold), and Glu (3.1-fold) and Asp (2.2-fold) levels increased.Moreover, our metabolomics data showing the activation of the purine nucleotide pathway, malate-aspartate shuttle, as well as creatine metabolism, which are known to be active during exercise, further suggests that PGC-1α regulates metabolism in exercise.Thus, we demonstrated the roles of PGC-1α in the skeletal muscle at the metabolite level.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan.

ABSTRACT
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α) is a coactivator of various nuclear receptors and other transcription factors whose expression increases in the skeletal muscle during exercise. We have previously made transgenic mice overexpressing PGC-1α in the skeletal muscle (PGC-1α-Tg mice). PGC-1α upregulates the expression of genes associated with red fibers, mitochondrial function, fatty acid oxidation, and branched chain amino acid (BCAA) degradation. However, global analyses of the actual metabolic products have not been investigated. In this study, we conducted metabolomic analysis of the skeletal muscle in PGC-1α-Tg mice by capillary electrophoresis with electrospray ionization time-of-flight mass spectrometry. Principal component analysis and hierarchical cluster analysis showed clearly distinguishable changes in the metabolites between PGC-1α-Tg and wild-type control mice. Changes were observed in metabolite levels of various metabolic pathways such as the TCA cycle, pentose phosphate pathway, nucleotide synthesis, purine nucleotide cycle, and amino acid metabolism, including BCAA and β-alanine. Namely, metabolic products of the TCA cycle increased in PGC-1α-Tg mice, with increased levels of citrate (2.3-fold), succinate (2.2-fold), fumarate (2.8-fold), and malate (2.3-fold) observed. Metabolic products associated with the pentose phosphate pathway and nucleotide biosynthesis also increased in PGC-1α-Tg mice. Meanwhile, BCAA levels decreased (Val, 0.7-fold; Leu, 0.8-fold; and Ile, 0.7-fold), and Glu (3.1-fold) and Asp (2.2-fold) levels increased. Levels of β-alanine and related metabolites were markedly decreased in PGC-1α-Tg mice. Coordinated regulation of the TCA cycle and amino acid metabolism, including BCAA, suggests that PGC-1α plays important roles in energy metabolism. Moreover, our metabolomics data showing the activation of the purine nucleotide pathway, malate-aspartate shuttle, as well as creatine metabolism, which are known to be active during exercise, further suggests that PGC-1α regulates metabolism in exercise. Thus, we demonstrated the roles of PGC-1α in the skeletal muscle at the metabolite level.

No MeSH data available.


Related in: MedlinePlus