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Dankel SN, Kalleklev TL, Tungland SL, Stafsnes MH, Bruheim P, Aloysius TA, Lindquist C, Skorve J, Nygård OK, Madsen L, Bjørndal B, Sydnes MO, Berge RK. Changes in Plasma Pyruvate and TCA Cycle Metabolites upon Increased Hepatic Fatty Acid Oxidation and Ketogenesis in Male Wistar Rats. Int J Mol Sci 2023; 24:15536. [PMID: 37958519 PMCID: PMC10648824 DOI: 10.3390/ijms242115536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/06/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Altered hepatic mitochondrial fatty acid β-oxidation and associated tricarboxylic acid (TCA) cycle activity contributes to lifestyle-related diseases, and circulating biomarkers reflecting these changes could have disease prognostic value. This study aimed to determine hepatic and systemic changes in TCA-cycle-related metabolites upon the selective pharmacologic enhancement of mitochondrial fatty acid β-oxidation in the liver, and to elucidate the mechanisms and potential markers of hepatic mitochondrial activity. Male Wistar rats were treated with 3-thia fatty acids (e.g., tetradecylthioacetic acid (TTA)), which target mitochondrial biogenesis, mitochondrial fatty acid β-oxidation, and ketogenesis predominantly in the liver. Hepatic and plasma concentrations of TCA cycle intermediates and anaplerotic substrates (LC-MS/MS), plasma ketones (colorimetric assay), and acylcarnitines (HPLC-MS/MS), along with associated TCA-cycle-related gene expression (qPCR) and enzyme activities, were determined. TTA-induced hepatic fatty acid β-oxidation resulted in an increased ratio of plasma ketone bodies/nonesterified fatty acid (NEFA), lower plasma malonyl-CoA levels, and a higher ratio of plasma acetylcarnitine/palmitoylcarnitine (C2/C16). These changes were associated with decreased hepatic and increased plasma pyruvate concentrations, and increased plasma concentrations of succinate, malate, and 2-hydroxyglutarate. Expression of several genes encoding TCA cycle enzymes and the malate-oxoglutarate carrier (Slc25a11), glutamate dehydrogenase (Gdh), and malic enzyme (Mdh1 and Mdh2) were significantly increased. In conclusion, the induction of hepatic mitochondrial fatty acid β-oxidation by 3-thia fatty acids lowered hepatic pyruvate while increasing plasma pyruvate, as well as succinate, malate, and 2-hydroxyglutarate.
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Affiliation(s)
- Simon Nitter Dankel
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
| | - Tine-Lise Kalleklev
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
| | - Siri Lunde Tungland
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, N-4021 Stavanger, Norway (M.O.S.)
| | - Marit Hallvardsdotter Stafsnes
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7491 Trondheim, Norway (P.B.)
| | - Per Bruheim
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7491 Trondheim, Norway (P.B.)
| | - Thomas Aquinas Aloysius
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
| | - Carine Lindquist
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
| | - Jon Skorve
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
| | - Ottar Kjell Nygård
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
- Department of Heart Disease, Haukeland University Hospital, N-5021 Bergen, Norway
| | - Lise Madsen
- Department of Clinical Medicine, University of Bergen, N-5021 Bergen, Norway;
| | - Bodil Bjørndal
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
- Department of Sports, Food and Natural Sciences, Western Norway University of Applied Sciences, N-5020 Bergen, Norway
| | - Magne Olav Sydnes
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, N-4021 Stavanger, Norway (M.O.S.)
| | - Rolf Kristian Berge
- Department of Clinical Science, University of Bergen, N-5021 Bergen, Norway (T.A.A.); (J.S.); (O.K.N.); (B.B.)
- Department of Heart Disease, Haukeland University Hospital, N-5021 Bergen, Norway
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Bjune MS, Lawrence-Archer L, Laupsa-Borge J, Sommersten CH, McCann A, Glastad RC, Johnston IG, Kern M, Blüher M, Mellgren G, Dankel SN. Metabolic role of the hepatic valine/3-hydroxyisobutyrate (3-HIB) pathway in fatty liver disease. EBioMedicine 2023; 91:104569. [PMID: 37084480 PMCID: PMC10148099 DOI: 10.1016/j.ebiom.2023.104569] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/30/2023] [Accepted: 03/30/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND The valine (branched-chain amino acid) metabolite 3-hydroxyisobutyrate (3-HIB), produced by 3-Hydroxyisobutyryl-CoA Hydrolase (HIBCH), is associated with insulin resistance and type 2 diabetes, but implicated tissues and cellular mechanisms are poorly understood. We hypothesized that HIBCH and 3-HIB regulate hepatic lipid accumulation. METHODS HIBCH mRNA in human liver biopsies ("Liver cohort") and plasma 3-HIB ("CARBFUNC" cohort) were correlated with fatty liver and metabolic markers. Human Huh7 hepatocytes were supplemented with fatty acids (FAs) to induce lipid accumulation. Following HIBCH overexpression, siRNA knockdown, inhibition of PDK4 (a marker of FA β-oxidation) or 3-HIB supplementation, we performed RNA-seq, Western blotting, targeted metabolite analyses and functional assays. FINDINGS We identify a regulatory feedback loop between the valine/3-HIB pathway and PDK4 that shapes hepatic FA metabolism and metabolic health and responds to 3-HIB treatment of hepatocytes. HIBCH overexpression increased 3-HIB release and FA uptake, while knockdown increased cellular respiration and decreased reactive oxygen species (ROS) associated with metabolic shifts via PDK4 upregulation. Treatment with PDK4 inhibitor lowered 3-HIB release and increased FA uptake, while increasing HIBCH mRNA. Implicating this regulatory loop in fatty liver, human cohorts show positive correlations of liver fat with hepatic HIBCH and PDK4 expression (Liver cohort) and plasma 3-HIB (CARBFUNC cohort). Hepatocyte 3-HIB supplementation lowered HIBCH expression and FA uptake and increased cellular respiration and ROS. INTERPRETATION These data implicate the hepatic valine/3-HIB pathway in mechanisms of fatty liver, reflected in increased plasma 3-HIB concentrations, and present possible targets for therapeutic intervention. FUNDING Funding was provided by the Research Council of Norway (263124/F20), the University of Bergen, the Western Norway Health Authorities, Novo Nordisk Scandinavia AS, the Trond Mohn Foundation and the Norwegian Diabetes Association.
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Affiliation(s)
- Mona Synnøve Bjune
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Laurence Lawrence-Archer
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Johnny Laupsa-Borge
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Bevital AS, Bergen, Norway
| | - Cathrine Horn Sommersten
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Mohn Nutrition Research Laboratory, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | | | | | - Iain George Johnston
- Department of Mathematics, University of Bergen, Bergen, Norway; Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Matthias Kern
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany; Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany; Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Gunnar Mellgren
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Simon N Dankel
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway.
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Mitochondrial Lipid Homeostasis at the Crossroads of Liver and Heart Diseases. Int J Mol Sci 2021; 22:ijms22136949. [PMID: 34203309 PMCID: PMC8268967 DOI: 10.3390/ijms22136949] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/19/2021] [Accepted: 06/25/2021] [Indexed: 12/16/2022] Open
Abstract
The prevalence of NAFLD (non-alcoholic fatty liver disease) is a rapidly increasing problem, affecting a huge population around the globe. However, CVDs (cardiovascular diseases) are the most common cause of mortality in NAFLD patients. Atherogenic dyslipidemia, characterized by plasma hypertriglyceridemia, increased small dense LDL (low-density lipoprotein) particles, and decreased HDL-C (high-density lipoprotein cholesterol) levels, is often observed in NAFLD patients. In this review, we summarize recent genetic evidence, proving the diverse nature of metabolic pathways involved in NAFLD pathogenesis. Analysis of available genetic data suggests that the altered operation of fatty-acid β-oxidation in liver mitochondria is the key process, connecting NAFLD-mediated dyslipidemia and elevated CVD risk. In addition, we discuss several NAFLD-associated genes with documented anti-atherosclerotic or cardioprotective effects, and current pharmaceutical strategies focused on both NAFLD treatment and reduction of CVD risk.
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Bjune MS, Lindquist C, Hallvardsdotter Stafsnes M, Bjørndal B, Bruheim P, Aloysius TA, Nygård O, Skorve J, Madsen L, Dankel SN, Berge RK. Plasma 3-hydroxyisobutyrate (3-HIB) and methylmalonic acid (MMA) are markers of hepatic mitochondrial fatty acid oxidation in male Wistar rats. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158887. [PMID: 33454435 DOI: 10.1016/j.bbalip.2021.158887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Discovery of specific markers that reflect altered hepatic fatty acid oxidation could help to detect an individual's risk of fatty liver, type 2 diabetes and cardiovascular disease at an early stage. Lipid and protein metabolism are intimately linked, but our understanding of this crosstalk remains limited. METHODS In male Wistar rats, we used synthetic fatty acid analogues (3-thia fatty acids) as a tool to induce hepatic fatty acid oxidation and mitochondrial biogenesis, to gain new insight into the link between fatty acid oxidation, amino acid metabolism and TCA cycle-related intermediate metabolites in liver and plasma. RESULTS Rats treated with 3-thia fatty acids had 3-fold higher hepatic, but not adipose and skeletal muscle, expression of the thioesterase 3-hydroxyisobutyryl-CoA hydrolase (Hibch), which controls the formation of 3-hydroxyisobutyrate (3-HIB) in the valine degradation pathway. Consequently, 3-thia fatty acid-stimulated hepatic fatty acid oxidation and ketogenesis was accompanied by decreased plasma 3-HIB and increased methylmalonic acid (MMA) concentrations further downstream in BCAA catabolism. The higher plasma MMA corresponded to higher MMA-CoA hydrolase activity and hepatic expression of GTP-specific succinyl-CoA synthase (Suclg2) and succinate dehydrogenase (Sdhb), and lower MMA-CoA mutase activity. Plasma 3-HIB correlated positively to plasma and hepatic concentrations of TAG, plasma total fatty acids, plasma NEFA and insulin/glucose ratio, while the reverse correlations were seen for MMA. CONCLUSION Our study provides new insight into TCA cycle-related metabolic changes associated with altered hepatic fatty acid flux, and identifies 3-HIB and MMA as novel circulating markers reflective of mitochondrial β-oxidation in male Wistar rats.
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Affiliation(s)
| | - Carine Lindquist
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Marit Hallvardsdotter Stafsnes
- Department of Biotechnology and Food Science, Faculty of Natural Sciences, NTNU Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Bodil Bjørndal
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Per Bruheim
- Department of Biotechnology and Food Science, Faculty of Natural Sciences, NTNU Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Thomas A Aloysius
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ottar Nygård
- Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
| | - Jon Skorve
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Lise Madsen
- Institute of Marine Research, NO-5817 Bergen, Norway
| | - Simon N Dankel
- Department of Clinical Science, University of Bergen, Bergen, Norway.
| | - Rolf Kristian Berge
- Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Heart Disease, Haukeland University Hospital, Bergen, Norway.
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