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- Agudelo, LZ, et al.
(författare)
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Skeletal muscle PGC-1α1 reroutes kynurenine metabolism to increase energy efficiency and fatigue-resistance
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 2767-
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Tidskriftsartikel (refereegranskat)abstract
- The coactivator PGC-1α1 is activated by exercise training in skeletal muscle and promotes fatigue-resistance. In exercised muscle, PGC-1α1 enhances the expression of kynurenine aminotransferases (Kats), which convert kynurenine into kynurenic acid. This reduces kynurenine-associated neurotoxicity and generates glutamate as a byproduct. Here, we show that PGC-1α1 elevates aspartate and glutamate levels and increases the expression of glycolysis and malate-aspartate shuttle (MAS) genes. These interconnected processes improve energy utilization and transfer fuel-derived electrons to mitochondrial respiration. This PGC-1α1-dependent mechanism allows trained muscle to use kynurenine metabolism to increase the bioenergetic efficiency of glucose oxidation. Kat inhibition with carbidopa impairs aspartate biosynthesis, mitochondrial respiration, and reduces exercise performance and muscle force in mice. Our findings show that PGC-1α1 activates the MAS in skeletal muscle, supported by kynurenine catabolism, as part of the adaptations to endurance exercise. This crosstalk between kynurenine metabolism and the MAS may have important physiological and clinical implications.
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- Pettersson-Klein, A. T., et al.
(författare)
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Small molecule PGC-1 alpha 1 protein stabilizers induce adipocyte Ucp1 expression and uncoupled mitochondrial respiration
- 2018
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Ingår i: Molecular metabolism. - : Elsevier BV. - 2212-8778. ; 9, s. 28-42
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The peroxisome proliferator-activated receptor-gamma coactivator-1 alpha 1 (PGC-1 alpha 1) regulates genes involved in energy metabolism. Increasing adipose tissue energy expenditure through PGC-1 alpha 1 activation is potentially beneficial for systemic metabolism. Pharmacological PGC-1 alpha 1 activators could be valuable tools in the fight against obesity and metabolic disease. Finding such compounds has been challenging partly because PGC-1 alpha 1 is a transcriptional coactivator with no known ligand-binding properties. While, PGC-1 alpha 1 activation is regulated by several mechanisms, protein stabilization is a crucial limiting step due to its short half-life under unstimulated conditions.Methods: We designed a cell-based high-throughput screening system to identify PGC-1 alpha 1 protein stabilizers. Positive hits were tested for their ability to induce endogenous PGC-1 alpha 1 protein accumulation and activate target gene expression in brown adipocytes. Select compounds were analyzed for their effects on global gene expression and cellular respiration in adipocytes.Results: Among 7,040 compounds screened, we highlight four small molecules with high activity as measured by: PGC-1 alpha 1 protein accumulation, target gene expression, and uncoupled mitochondrial respiration in brown adipocytes.Conclusions: We identify compounds that induce PGC-1 alpha 1 protein accumulation and show that this increases uncoupled respiration in brown adipocytes. This screening platform establishes the foundation for a new class of therapeutics with potential use in obesity and associated disorders.
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