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Helsley RN, Park SH, Vekaria HJ, Sullivan PG, Conroy LR, Sun RC, Romero MDM, Herrero L, Bons J, King CD, Rose J, Meyer JG, Schilling B, Kahn CR, Softic S. Ketohexokinase-C regulates global protein acetylation to decrease carnitine palmitoyltransferase 1a-mediated fatty acid oxidation. J Hepatol 2023; 79:25-42. [PMID: 36822479 PMCID: PMC10679901 DOI: 10.1016/j.jhep.2023.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/25/2023]
Abstract
BACKGROUND & AIMS The consumption of sugar and a high-fat diet (HFD) promotes the development of obesity and metabolic dysfunction. Despite their well-known synergy, the mechanisms by which sugar worsens the outcomes associated with a HFD are largely elusive. METHODS Six-week-old, male, C57Bl/6 J mice were fed either chow or a HFD and were provided with regular, fructose- or glucose-sweetened water. Moreover, cultured AML12 hepatocytes were engineered to overexpress ketohexokinase-C (KHK-C) using a lentivirus vector, while CRISPR-Cas9 was used to knockdown CPT1α. The cell culture experiments were complemented with in vivo studies using mice with hepatic overexpression of KHK-C and in mice with liver-specific CPT1α knockout. We used comprehensive metabolomics, electron microscopy, mitochondrial substrate phenotyping, proteomics and acetylome analysis to investigate underlying mechanisms. RESULTS Fructose supplementation in mice fed normal chow and fructose or glucose supplementation in mice fed a HFD increase KHK-C, an enzyme that catalyzes the first step of fructolysis. Elevated KHK-C is associated with an increase in lipogenic proteins, such as ACLY, without affecting their mRNA expression. An increase in KHK-C also correlates with acetylation of CPT1α at K508, and lower CPT1α protein in vivo. In vitro, KHK-C overexpression lowers CPT1α and increases triglyceride accumulation. The effects of KHK-C are, in part, replicated by a knockdown of CPT1α. An increase in KHK-C correlates negatively with CPT1α protein levels in mice fed sugar and a HFD, but also in genetically obese db/db and lipodystrophic FIRKO mice. Mechanistically, overexpression of KHK-C in vitro increases global protein acetylation and decreases levels of the major cytoplasmic deacetylase, SIRT2. CONCLUSIONS KHK-C-induced acetylation is a novel mechanism by which dietary fructose augments lipogenesis and decreases fatty acid oxidation to promote the development of metabolic complications. IMPACT AND IMPLICATIONS Fructose is a highly lipogenic nutrient whose negative consequences have been largely attributed to increased de novo lipogenesis. Herein, we show that fructose upregulates ketohexokinase, which in turn modifies global protein acetylation, including acetylation of CPT1a, to decrease fatty acid oxidation. Our findings broaden the impact of dietary sugar beyond its lipogenic role and have implications on drug development aimed at reducing the harmful effects attributed to sugar metabolism.
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Affiliation(s)
- Robert N Helsley
- Department of Pediatrics and Gastroenterology, University of Kentucky, Lexington, KY, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA; Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Se-Hyung Park
- Department of Pediatrics and Gastroenterology, University of Kentucky, Lexington, KY, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Hemendra J Vekaria
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA
| | - Lindsey R Conroy
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Ramon C Sun
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA; Department of Biochemistry & Molecular Biology, University of Florida, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida, Gainesville, FL, USA
| | - María Del Mar Romero
- School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, 08028, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, 28029, Spain
| | - Laura Herrero
- School of Pharmacy, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, 08028, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, 28029, Spain
| | - Joanna Bons
- Chemistry & Mass Spectrometry, Buck Institute for Research on Aging, Novato, CA, USA
| | - Christina D King
- Chemistry & Mass Spectrometry, Buck Institute for Research on Aging, Novato, CA, USA
| | - Jacob Rose
- Chemistry & Mass Spectrometry, Buck Institute for Research on Aging, Novato, CA, USA
| | - Jesse G Meyer
- Chemistry & Mass Spectrometry, Buck Institute for Research on Aging, Novato, CA, USA; Department of Computational Biomedicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Birgit Schilling
- Chemistry & Mass Spectrometry, Buck Institute for Research on Aging, Novato, CA, USA
| | - C Ronald Kahn
- Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Samir Softic
- Department of Pediatrics and Gastroenterology, University of Kentucky, Lexington, KY, USA; Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA; Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, MA, USA.
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Angelini A, Saha PK, Jain A, Jung SY, Mynatt RL, Pi X, Xie L. PHDs/CPT1B/VDAC1 axis regulates long-chain fatty acid oxidation in cardiomyocytes. Cell Rep 2021; 37:109767. [PMID: 34610308 PMCID: PMC8658754 DOI: 10.1016/j.celrep.2021.109767] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 05/19/2021] [Accepted: 09/02/2021] [Indexed: 12/23/2022] Open
Abstract
Cardiac metabolism is a high-oxygen-consuming process, showing a preference for long-chain fatty acid (LCFA) as the fuel source under physiological conditions. However, a metabolic switch (favoring glucose instead of LCFA) is commonly reported in ischemic or late-stage failing hearts. The mechanism regulating this metabolic switch remains poorly understood. Here, we report that loss of PHD2/3, the cellular oxygen sensors, blocks LCFA mitochondria uptake and β-oxidation in cardiomyocytes. In high-fat-fed mice, PHD2/3 deficiency improves glucose metabolism but exacerbates the cardiac defects. Mechanistically, we find that PHD2/3 bind to CPT1B, a key enzyme of mitochondrial LCFA uptake, promoting CPT1B-P295 hydroxylation. Further, we show that CPT1B-P295 hydroxylation is indispensable for its interaction with VDAC1 and LCFA β-oxidation. Finally, we demonstrate that a CPT1B-P295A mutant constitutively binds to VDAC1 and rescues LCFA metabolism in PHD2/3-deficient cardiomyocytes. Together, our data identify an oxygen-sensitive regulatory axis involved in cardiac metabolism.
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Affiliation(s)
- Aude Angelini
- Department of Medicine, Section of Athero & Lipo, Baylor College of Medicine, Houston, TX 77030, USA; Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pradip K Saha
- Department of Medicine, Division of Diabetes, Endocrinology & Metabolism, Diabetes Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Antrix Jain
- Department of Biochemistry and Molecular Biology, Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sung Yun Jung
- Department of Biochemistry and Molecular Biology, Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Randall L Mynatt
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Xinchun Pi
- Department of Medicine, Section of Athero & Lipo, Baylor College of Medicine, Houston, TX 77030, USA; Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Liang Xie
- Department of Medicine, Section of Athero & Lipo, Baylor College of Medicine, Houston, TX 77030, USA; Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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Angelini A, Pi X, Xie L. Dioxygen and Metabolism; Dangerous Liaisons in Cardiac Function and Disease. Front Physiol 2017; 8:1044. [PMID: 29311974 PMCID: PMC5732914 DOI: 10.3389/fphys.2017.01044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/29/2017] [Indexed: 12/19/2022] Open
Abstract
The heart must consume a significant amount of energy to sustain its contractile activity. Although the fuel demands are huge, the stock remains very low. Thus, in order to supply its daily needs, the heart must have amazing adaptive abilities, which are dependent on dioxygen availability. However, in myriad cardiovascular diseases, “fuel” depletion and hypoxia are common features, leading cardiomyocytes to favor low-dioxygen-consuming glycolysis rather than oxidation of fatty acids. This metabolic switch makes it challenging to distinguish causes from consequences in cardiac pathologies. Finally, despite the progress achieved in the past few decades, medical treatments have not improved substantially, either. In such a situation, it seems clear that much remains to be learned about cardiac diseases. Therefore, in this review, we will discuss how reconciling dioxygen availability and cardiac metabolic adaptations may contribute to develop full and innovative strategies from bench to bedside.
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Affiliation(s)
- Aude Angelini
- Department of Medicine-Athero and Lipo, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, United States
| | - Xinchun Pi
- Department of Medicine-Athero and Lipo, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, United States
| | - Liang Xie
- Department of Medicine-Athero and Lipo, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, United States
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Kuwahara K, Harada K, Yamagoshi R, Yamamoto T, Shinohara Y. Effects of employment of distinct strategies to capture antibody on antibody delivery into cultured cells. Mol Cell Biochem 2015; 404:25-30. [PMID: 25697272 DOI: 10.1007/s11010-015-2362-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 02/14/2015] [Indexed: 11/24/2022]
Abstract
The characteristics of antibody delivery into cultured HeLa cells were examined using two delivery systems. Both systems used a cell-penetrating peptide as a tool for intrusion of an antibody into the cells, but either a "protein A derivative" or "hydrophobic motif" was employed to capture the antibody. When we examined the uptake of the Alexa Fluor-labeled antibody by the use of these two systems, both systems were found to effectively deliver the antibody into the cultured cells. However, when we compared the amount of antibody delivered by these systems with the amount of transferrin uptake, the former was 10 times smaller than the latter. The lower efficiency of antibody delivery than transferrin uptake seemed to be attributable to the involvement of the antibody delivery reagent, which failed to catch the antibody molecule. This interpretation was validated by an experiment using a larger amount of antibody, and the amount of antibody delivered by the "protein A derivative" system under this condition was determined to be 13 ng proteins/10(5) cells. The antibody delivery achieved by the "protein A derivative" or "hydrophobic motif" showed two differences, i.e., a difference in intracellular distribution of the delivered antibody molecules and a difference in the fluorescence spectrum observed with cellular lysates. Possible reasons for these differences between the two delivery systems are discussed.
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Affiliation(s)
- Kana Kuwahara
- Institute for Genome Research, University of Tokushima, Kuramoto-cho-3, Tokushima, 770-8503, Japan
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Comparison of the catalytic activities of three isozymes of carnitine palmitoyltransferase 1 expressed in COS7 cells. Appl Biochem Biotechnol 2013; 172:1486-96. [PMID: 24222496 DOI: 10.1007/s12010-013-0619-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/30/2013] [Indexed: 12/30/2022]
Abstract
The enzyme carnitine palmitoyltransferase 1 (CPT1) catalyzes the transfer of an acyl group from acyl-CoA to carnitine to form acylcarnitine, and three isozymes of it, 1a, 1b, and 1c, have been identified. Interestingly, the 1c isozyme was reported to show no enzymatic activity, but it was not clearly demonstrated whether this inactivity was due to its dysfunction or due to its poor expression. In the present study, we (a) expressed individual CPT1 isozymes in COS7 cells, (b) evaluated quantitatively their expression levels by Western blotting using the three bacterially expressed CPT1 isozymes as standards, and (c) evaluated their catalytic activities. With these experiments, we successfully demonstrated that the absence of the enzymatic activity of the 1c isozyme was due to its dysfunction. In addition, experiments on the preparation of standard CPT1 isozymes revealed that the 1c isozyme did not show the standard relationship between migration in an SDS-PAGE gel and molecular size. We further tried to determine why the 1c isozyme was inert by preparing chimeric CPT1 between 1a and 1c, but no clear conclusion could be drawn because one of the chimeric CPT1s was not sufficiently expressed.
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