Elevated liver glycogenolysis mediates higher blood glucose during acute exercise in Barth syndrome.

Autor: Schweitzer GG; Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, United States of America., Ditzenberger GL; Doctor of Physical Therapy Division, Duke University School of Medicine, Durham, NC, United States of America., Hughey CC; Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, MN, United States of America., Finck BN; Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, United States of America., Martino MR; Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, United States of America., Pacak CA; Department of Neurology, University of Minnesota School of Medicine, Minneapolis, MN, United States of America., Byrne BJ; Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, United States of America., Cade WT; Doctor of Physical Therapy Division, Duke University School of Medicine, Durham, NC, United States of America.; Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2023 Aug 31; Vol. 18 (8), pp. e0290832. Date of Electronic Publication: 2023 Aug 31 (Print Publication: 2023).
DOI: 10.1371/journal.pone.0290832
Abstrakt: Barth syndrome (BTHS) is an X-linked recessive genetic disorder due to mutations in the Tafazzin (TAFAZZIN) gene that lead to cardiac and skeletal muscle mitochondrial dysfunction. Previous studies in humans with BTHS demonstrate that the defects in muscle mitochondrial oxidative metabolism result in an enhanced reliance on anaerobic metabolism during exercise to meet energy demands of muscular work. During exercise, the liver normally increases glucose production via glycogenolysis and gluconeogenesis to match the elevated rate of muscle glucose uptake and meet the ATP requirements of working muscle. However, the impact of Tafazzin deficiency on hepatic glucose production and the pathways contributing to hepatic glucose production during exercise is unknown. Therefore, the purpose of this study was to quantify in vivo liver gluconeogenesis and glycogenolysis in Tafazzin knockdown mice at rest and during acute exercise.
Methods: Male TAFAZZIN shRNA transgenic (TG) and wild-type (WT) mice completed exhaustive treadmill running protocols to test exercise tolerance. Mice underwent 2H- and 13C-stable isotope infusions at rest and during a 30-minute treadmill running bout to quantify hepatic glucose production and associated nutrient fluxes under sedentary conditions and during acute exercise. Circulating and tissue (skeletal muscle and liver) samples were obtained during and following exercise to assess static metabolite levels.
Results: TG mice reached exhaustion sooner during exhaustive treadmill running protocols and exhibited higher plasma lactate concentrations after exhaustive exercise compared to WT mice. Arterial glucose levels were comparable between genotypes at rest, but higher in TG mice compared to WT mice during exercise. Consistent with the higher blood glucose, TG mice showed increased endogenous glucose production owing to elevated glycogenolysis compared to WT mice during exercise. Total gluconeogenesis, gluconeogenesis from glycerol, gluconeogenesis from phosphoenolpyruvate, pyruvate cycling, total cataplerosis, and anaplerotic fluxes were similar between TG and WT mice at rest and during exercise. However, lactate dehydrogenase flux and TCA cycle fluxes trended higher in TG mice during exercise. Liver glycogen content in TG was higher in TG vs. controls.
Conclusion: Our data in the Tafazzin knockdown mouse suggest that elevated anaerobic metabolism during rest and exercise previously reported in humans with BTHS are supported by the finding of higher hepatic glycogenolysis.
Competing Interests: The authors declared no conflict of interest.
(Copyright: © 2023 Schweitzer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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