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Acevedo A, Jones AE, Danna BT, Turner R, Montales KP, Benincá C, Reue K, Shirihai OS, Stiles L, Wallace M, Wang Y, Bertholet AM, Divakaruni AS. The BCKDK inhibitor BT2 is a chemical uncoupler that lowers mitochondrial ROS production and de novo lipogenesis. J Biol Chem 2024; 300:105702. [PMID: 38301896 PMCID: PMC10910128 DOI: 10.1016/j.jbc.2024.105702] [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: 08/15/2023] [Revised: 01/12/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024] Open
Abstract
Elevated levels of branched chain amino acids (BCAAs) and branched-chain α-ketoacids are associated with cardiovascular and metabolic disease, but the molecular mechanisms underlying a putative causal relationship remain unclear. The branched-chain ketoacid dehydrogenase kinase (BCKDK) inhibitor BT2 (3,6-dichlorobenzo[b]thiophene-2-carboxylic acid) is often used in preclinical models to increase BCAA oxidation and restore steady-state BCAA and branched-chain α-ketoacid levels. BT2 administration is protective in various rodent models of heart failure and metabolic disease, but confoundingly, targeted ablation of Bckdk in specific tissues does not reproduce the beneficial effects conferred by pharmacologic inhibition. Here, we demonstrate that BT2, a lipophilic weak acid, can act as a mitochondrial uncoupler. Measurements of oxygen consumption, mitochondrial membrane potential, and patch-clamp electrophysiology show that BT2 increases proton conductance across the mitochondrial inner membrane independently of its inhibitory effect on BCKDK. BT2 is roughly sixfold less potent than the prototypical uncoupler 2,4-dinitrophenol and phenocopies 2,4-dinitrophenol in lowering de novo lipogenesis and mitochondrial superoxide production. The data suggest that the therapeutic efficacy of BT2 may be attributable to the well-documented effects of mitochondrial uncoupling in alleviating cardiovascular and metabolic disease.
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Affiliation(s)
- Aracely Acevedo
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California, USA
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California, USA
| | - Bezawit T Danna
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California, USA
| | - Rory Turner
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Katrina P Montales
- Department of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Cristiane Benincá
- Department of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Karen Reue
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, USA
| | - Orian S Shirihai
- Department of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Linsey Stiles
- Department of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Martina Wallace
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Yibin Wang
- DukeNUS School of Medicine, Signature Research Program in Cardiovascular and Metabolic Diseases, Singapore, Singapore
| | - Ambre M Bertholet
- Department of Physiology, University of California, Los Angeles, Los Angeles, California, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California, USA.
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Acevedo A, Jones AE, Danna BT, Turner R, Montales KP, Benincá C, Reue K, Shirihai OS, Stiles L, Wallace M, Wang Y, Bertholet AM, Divakaruni AS. The BCKDK inhibitor BT2 is a chemical uncoupler that lowers mitochondrial ROS production and de novo lipogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553413. [PMID: 37645724 PMCID: PMC10461965 DOI: 10.1101/2023.08.15.553413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Elevated levels of branched chain amino acids (BCAAs) and branched-chain α-ketoacids (BCKAs) are associated with cardiovascular and metabolic disease, but the molecular mechanisms underlying a putative causal relationship remain unclear. The branched-chain ketoacid dehydrogenase kinase (BCKDK) inhibitor BT2 is often used in preclinical models to increase BCAA oxidation and restore steady-state BCAA and BCKA levels. BT2 administration is protective in various rodent models of heart failure and metabolic disease, but confoundingly, targeted ablation of Bckdk in specific tissues does not reproduce the beneficial effects conferred by pharmacologic inhibition. Here we demonstrate that BT2, a lipophilic weak acid, can act as a mitochondrial uncoupler. Measurements of oxygen consumption, mitochondrial membrane potential, and patch-clamp electrophysiology show BT2 increases proton conductance across the mitochondrial inner membrane independently of its inhibitory effect on BCKDK. BT2 is roughly five-fold less potent than the prototypical uncoupler 2,4-dinitrophenol (DNP), and phenocopies DNP in lowering de novo lipogenesis and mitochondrial superoxide production. The data suggest the therapeutic efficacy of BT2 may be attributable to the well-documented effects of mitochondrial uncoupling in alleviating cardiovascular and metabolic disease.
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Affiliation(s)
- Aracely Acevedo
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Bezawit T Danna
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Rory Turner
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Katrina P Montales
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Cristiane Benincá
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Karen Reue
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Orian S Shirihai
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Linsey Stiles
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Martina Wallace
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Yibin Wang
- DukeNUS School of Medicine, Signature Research Program in Cardiovascular and Metabolic Diseases, 8 College Road, Mail Code 169857, Singapore
| | - Ambre M Bertholet
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
- Lead contact
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