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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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Desousa BR, Kim KKO, Jones AE, Ball AB, Hsieh WY, Swain P, Morrow DH, Brownstein AJ, Ferrick DA, Shirihai OS, Neilson A, Nathanson DA, Rogers GW, Dranka BP, Murphy AN, Affourtit C, Bensinger SJ, Stiles L, Romero N, Divakaruni AS. Calculation of ATP production rates using the Seahorse XF Analyzer. EMBO Rep 2023; 24:e56380. [PMID: 37548091 PMCID: PMC10561364 DOI: 10.15252/embr.202256380] [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: 10/26/2022] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 08/08/2023] Open
Abstract
Oxidative phosphorylation and glycolysis are the dominant ATP-generating pathways in mammalian metabolism. The balance between these two pathways is often shifted to execute cell-specific functions in response to stimuli that promote activation, proliferation, or differentiation. However, measurement of these metabolic switches has remained mostly qualitative, making it difficult to discriminate between healthy, physiological changes in energy transduction or compensatory responses due to metabolic dysfunction. We therefore present a broadly applicable method to calculate ATP production rates from oxidative phosphorylation and glycolysis using Seahorse XF Analyzer data and empirical conversion factors. We quantify the bioenergetic changes observed during macrophage polarization as well as cancer cell adaptation to in vitro culture conditions. Additionally, we detect substantive changes in ATP utilization upon neuronal depolarization and T cell receptor activation that are not evident from steady-state ATP measurements. This method generates a single readout that allows the direct comparison of ATP produced from oxidative phosphorylation and glycolysis in live cells. Additionally, the manuscript provides a framework for tailoring the calculations to specific cell systems or experimental conditions.
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Affiliation(s)
- Brandon R Desousa
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | - Kristen KO Kim
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | - Anthony E Jones
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | - Andréa B Ball
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | - Wei Y Hsieh
- Department of Microbiology, Immunology, and Molecular GeneticsUniversity of California, Los AngelesLos AngelesCAUSA
| | | | - Danielle H Morrow
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | | | | | - Orian S Shirihai
- Department of MedicineUniversity of California, Los AngelesLos AngelesCAUSA
| | | | - David A Nathanson
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
| | | | | | | | | | - Steven J Bensinger
- Department of Microbiology, Immunology, and Molecular GeneticsUniversity of California, Los AngelesLos AngelesCAUSA
| | - Linsey Stiles
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
- Department of MedicineUniversity of California, Los AngelesLos AngelesCAUSA
| | | | - Ajit S Divakaruni
- Department of Molecular and Medical PharmacologyUniversity of California, Los AngelesLos AngelesCAUSA
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3
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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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Iida M, Harari PM, Wheeler DL, Toulany M. Targeting AKT/PKB to improve treatment outcomes for solid tumors. Mutat Res 2020; 819-820:111690. [PMID: 32120136 DOI: 10.1016/j.mrfmmm.2020.111690] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/31/2020] [Accepted: 02/11/2020] [Indexed: 12/16/2022]
Abstract
The serine/threonine kinase AKT, also known as protein kinase B (PKB), is the major substrate to phosphoinositide 3-kinase (PI3K) and consists of three paralogs: AKT1 (PKBα), AKT2 (PKBβ) and AKT3 (PKBγ). The PI3K/AKT pathway is normally activated by binding of ligands to membrane-bound receptor tyrosine kinases (RTKs) as well as downstream to G-protein coupled receptors and integrin-linked kinase. Through multiple downstream substrates, activated AKT controls a wide variety of cellular functions including cell proliferation, survival, metabolism, and angiogenesis in both normal and malignant cells. In human cancers, the PI3K/AKT pathway is most frequently hyperactivated due to mutations and/or overexpression of upstream components. Aberrant expression of RTKs, gain of function mutations in PIK3CA, RAS, PDPK1, and AKT itself, as well as loss of function mutation in AKT phosphatases are genetic lesions that confer hyperactivation of AKT. Activated AKT stimulates DNA repair, e.g. double strand break repair after radiotherapy. Likewise, AKT attenuates chemotherapy-induced apoptosis. These observations suggest that a crucial link exists between AKT and DNA damage. Thus, AKT could be a major predictive marker of conventional cancer therapy, molecularly targeted therapy, and immunotherapy for solid tumors. In this review, we summarize the current understanding by which activated AKT mediates resistance to cancer treatment modalities, i.e. radiotherapy, chemotherapy, and RTK targeted therapy. Next, the effect of AKT on response of tumor cells to RTK targeted strategies will be discussed. Finally, we will provide a brief summary on the clinical trials of AKT inhibitors in combination with radiochemotherapy, RTK targeted therapy, and immunotherapy.
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Affiliation(s)
- M Iida
- Department of Human Oncology, University of Wisconsin in Madison, Madison, WI, USA.
| | - P M Harari
- Department of Human Oncology, University of Wisconsin in Madison, Madison, WI, USA
| | - D L Wheeler
- Department of Human Oncology, University of Wisconsin in Madison, Madison, WI, USA
| | - M Toulany
- Division of Radiobiology and Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany; German Cancer Consortium (DKTK), Partner Site Tuebingen, and German Cancer Research Center (DKFZ), Heidelberg, Germany.
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5
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Yu Y, Xiong Y, Ladeiras D, Yang Z, Ming XF. Myosin 1b Regulates Nuclear AKT Activation by Preventing Localization of PTEN in the Nucleus. iScience 2019; 19:39-53. [PMID: 31349190 PMCID: PMC6660601 DOI: 10.1016/j.isci.2019.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/17/2019] [Accepted: 07/05/2019] [Indexed: 02/08/2023] Open
Abstract
Insulin-induced AKT activation is dependent on phosphoinositide 3-kinase and opposed by tumor suppressor phosphatase and tensin homolog (PTEN). Our previous study demonstrates that myosin 1b (MYO1B) mediates arginase-II-induced activation of mechanistic target of rapamycin complex 1 that is regulated by AKT. However, the role of MYO1B in AKT activation is unknown. Here we show that silencing MYO1B in mouse embryonic fibroblasts (MEF) inhibits insulin-induced nuclear but not cytoplasmic AKT activation accompanied by elevated nuclear PTEN level. Co-immunoprecipitation, co-immunostaining, and proximity ligation assay show an interaction of MYO1B and PTEN resulting in reduced nuclear PTEN. Moreover, the elevated nuclear PTEN upon silencing MYO1B promotes apoptosis of MEFs and melanoma B16F10 cells. Taken together, we demonstrate that MYO1B, by interacting with PTEN, prevents nuclear localization of PTEN contributing to nuclear AKT activation and suppression of cell apoptosis. This may present a therapeutic approach for cancer treatment such as melanoma. MYO1B, by interacting with PTEN, prevents PTEN localization in the nucleus MYO1B prevents nuclear localization of PTEN depending on its motor activity This contributes to nuclear AKT activation and suppression of cell apoptosis Targeting MYO1B may represent a therapeutic approach for cancer treatment
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Affiliation(s)
- Yi Yu
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Yuyan Xiong
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Diogo Ladeiras
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Zhihong Yang
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
| | - Xiu-Fen Ming
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
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6
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Divakaruni AS, Hsieh WY, Minarrieta L, Duong TN, Kim KKO, Desousa BR, Andreyev AY, Bowman CE, Caradonna K, Dranka BP, Ferrick DA, Liesa M, Stiles L, Rogers GW, Braas D, Ciaraldi TP, Wolfgang MJ, Sparwasser T, Berod L, Bensinger SJ, Murphy AN. Etomoxir Inhibits Macrophage Polarization by Disrupting CoA Homeostasis. Cell Metab 2018; 28:490-503.e7. [PMID: 30043752 PMCID: PMC6125190 DOI: 10.1016/j.cmet.2018.06.001] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/20/2018] [Accepted: 06/02/2018] [Indexed: 12/12/2022]
Abstract
Long-chain fatty acid (LCFA) oxidation has been shown to play an important role in interleukin-4 (IL-4)-mediated macrophage polarization (M(IL-4)). However, many of these conclusions are based on the inhibition of carnitine palmitoyltransferase-1 with high concentrations of etomoxir that far exceed what is required to inhibit enzyme activity (EC90 < 3 μM). We employ genetic and pharmacologic models to demonstrate that LCFA oxidation is largely dispensable for IL-4-driven polarization. Unexpectedly, high concentrations of etomoxir retained the ability to disrupt M(IL-4) polarization in the absence of Cpt1a or Cpt2 expression. Although excess etomoxir inhibits the adenine nucleotide translocase, oxidative phosphorylation is surprisingly dispensable for M(IL-4). Instead, the block in polarization was traced to depletion of intracellular free coenzyme A (CoA), likely resulting from conversion of the pro-drug etomoxir into active etomoxiryl CoA. These studies help explain the effect(s) of excess etomoxir on immune cells and reveal an unappreciated role for CoA metabolism in macrophage polarization.
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Affiliation(s)
- Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Wei Yuan Hsieh
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lucía Minarrieta
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Tin N Duong
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kristen K O Kim
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brandon R Desousa
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander Y Andreyev
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlyn E Bowman
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kacey Caradonna
- Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA 95051, USA
| | - Brian P Dranka
- Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA 95051, USA
| | - David A Ferrick
- Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA 95051, USA
| | - Marc Liesa
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Linsey Stiles
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - George W Rogers
- Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA 95051, USA
| | - Daniel Braas
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; UCLA Metabolomics Center and Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Theodore P Ciaraldi
- Veterans Affairs San Diego Healthcare System, La Jolla, CA 92161, USA; Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael J Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tim Sparwasser
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Luciana Berod
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Steven J Bensinger
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
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Dong W, Guan F, Zhang X, Gao S, Liu N, Chen W, Zhang L, Lu D. Dhcr24 activates the PI3K/Akt/HKII pathway and protects against dilated cardiomyopathy in mice. Animal Model Exp Med 2018; 1:40-52. [PMID: 30891546 PMCID: PMC6354314 DOI: 10.1002/ame2.12007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/16/2018] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND 24-dehydrocholesterol reductase (Dhcr24) catalyzes the last step of cholesterol biosynthesis, which is required for normal development and anti-apoptotic activities of tissues. We found that Dhcr24 expression decreased in the cTnTR 141W dilated cardiomyopathy (DCM) transgenic mice. Therefore, we tested whether rescued expression of Dhcr24 could prevent the development of DCM and its possible mechanism. METHODS Heart tissue specific transgenic overexpression mice of Dhcr24 was generated, then was crossed to cTnTR 141W mouse to obtain the double transgenic mouse (DTG). The phenotypes were demonstrated by the survival, cardiac geometry and function analysis, as well as microstructural and ultrastructural observations based on echocardiography and histology examination. The pathway and apoptosis were analysed by western blotting and TUNEL assay in vivo and in vitro. RESULTS We find that Dhcr24 decreased in hearts tissues of cTnTR 141W and LMNAE 82K DCM mice. The transgenic overexpression of Dhcr24 significantly improves DCM phenotypes in cTnTR 141W mice, and activates PI3K/Akt/HKII pathway, followed by a reduction of the translocation of Bax and release of cytochrome c, caspase-9 and caspase-3 activation and myocyte apoptosis. Knockdown the expression of Dhcr24 reduces the activation of PI3K/Akt/HKII pathway and inhibition of the mitochondrial-dependent apoptosis. The anti-apoptotic effect of Dhcr24 could be completely removed by the inhibition of PI3K pathway and partly removed by the HKII inhibitor in H9c2 cell line. CONCLUSION Compensatory expression of Dhcr24 protect against DCM through activated PI3K/Akt/HKII pathway and reduce Bax translocation. This is the first investigation for the molecular mechanism of Dhcr24 participate in development of DCM.
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Affiliation(s)
- Wei Dong
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Fei‐fei Guan
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Xu Zhang
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Shan Gao
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Ning Liu
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Wei Chen
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Lian‐feng Zhang
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
| | - Dan Lu
- Key Laboratory of Human Disease Comparative MedicineNHFPCInstitute of Laboratory Animal ScienceChinese Academy of Medical Sciences & Comparative Medical CenterPeking Union Medical CollegeBeijingChina
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8
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Breivik L, Jensen A, Guvåg S, Aarnes EK, Aspevik A, Helgeland E, Hovland S, Brattelid T, Jonassen AK. B-type natriuretic peptide expression and cardioprotection is regulated by Akt dependent signaling at early reperfusion. Peptides 2015; 66:43-50. [PMID: 25698234 DOI: 10.1016/j.peptides.2015.01.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 01/16/2023]
Abstract
Exogenously administered B-type natriuretic peptide (BNP) has been shown to offer cardioprotection through activation of particulate guanylyl cyclase (pGC), protein kinase G (PKG) and KATP channel opening. The current study explores if cardioprotection afforded by short intermittent BNP administration involves PI3K/Akt/p70s6k dependent signaling, and whether this signaling pathway may participate in regulation of BNP mRNA expression at early reperfusion. Isolated Langendorff perfused rat hearts were subjected to 30min of regional ischemia and 120min of reperfusion (IR). Applying intermittent 3×30s infusion of BNP peptide in a postconditioning like manner (BNPPost) reduced infarct size by >50% compared to controls (BNPPost 17±2% vs. control 42±4%, p<0.001). Co-treatment with inhibitors of the PI3K/Akt/p70s6k pathway (wortmannin, SH-6 and rapamycin) completely abolished the infarct-limiting effect of BNP postconditioning (BNPPost+Wi 36±5%, BNPPost+SH-6 41±4%, BNPPost+Rap 37±6% vs. BNPPost 17±2%, p<0.001). Inhibition of natriuretic peptide receptors (NPR) by isatin also abrogated BNPPost cardioprotection (BNPPost+isatin 46±2% vs. BNPPost 17±2%, p<0.001). BNPPost also significantly phosphorylated Akt and p70s6k at early reperfusion, and Akt phosphorylation was inhibited by SH-6 and isatin. Myocardial BNP mRNA levels in the area at risk (AA) were significantly elevated at early reperfusion as compared to the non-ischemic area (ANA) (Ctr(AA) 2.7±0.5 vs. Ctr(ANA) 1.2±0.2, p<0.05) and the ischemic control tissue (Ctr(AA) 2.7±0.5 vs. ischemia 1.0±0.1, p<0.05). Additional experiments also revealed a significant higher BNP mRNA level in ischemic postconditioned (IPost) hearts as compared to ischemic controls (IPost 6.7±1.3 vs. ischemia 1.0±0.2, p<0.05), but showed no difference from controls run in parallel (Ctr 5.4±0.8). Akt inhibition by SH-6 completely abrogated this elevation (IPost 6.7±1.3 vs. IPost+SH-6 1.8±0.7, p<0.05) (Ctr 5.4±0.8 vs. SH-6 1.5±0.9, p<0.05). In conclusion, Akt dependent signaling is involved in mediating the cardioprotection afforded by intermittent BNP infusion at early reperfusion, and may also participate in regulation of reperfusion induced BNP expression.
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Affiliation(s)
- L Breivik
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway.
| | - A Jensen
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - S Guvåg
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - E K Aarnes
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - A Aspevik
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - E Helgeland
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - S Hovland
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - T Brattelid
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - A K Jonassen
- Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Norway
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9
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Thiazolidinediones are acute, specific inhibitors of the mitochondrial pyruvate carrier. Proc Natl Acad Sci U S A 2013; 110:5422-7. [PMID: 23513224 DOI: 10.1073/pnas.1303360110] [Citation(s) in RCA: 218] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Facilitated pyruvate transport across the mitochondrial inner membrane is a critical step in carbohydrate, amino acid, and lipid metabolism. We report that clinically relevant concentrations of thiazolidinediones (TZDs), a widely used class of insulin sensitizers, acutely and specifically inhibit mitochondrial pyruvate carrier (MPC) activity in a variety of cell types. Respiratory inhibition was overcome with methyl pyruvate, localizing the effect to facilitated pyruvate transport, and knockdown of either paralog, MPC1 or MPC2, decreased the EC50 for respiratory inhibition by TZDs. Acute MPC inhibition significantly enhanced glucose uptake in human skeletal muscle myocytes after 2 h. These data (i) report that clinically used TZDs inhibit the MPC, (ii) validate that MPC1 and MPC2 are obligatory components of facilitated pyruvate transport in mammalian cells, (iii) indicate that the acute effect of TZDs may be related to insulin sensitization, and (iv) establish mitochondrial pyruvate uptake as a potential therapeutic target for diseases rooted in metabolic dysfunction.
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Martelli AM, Tabellini G, Bressanin D, Ognibene A, Goto K, Cocco L, Evangelisti C. The emerging multiple roles of nuclear Akt. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:2168-78. [PMID: 22960641 DOI: 10.1016/j.bbamcr.2012.08.017] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 08/20/2012] [Accepted: 08/23/2012] [Indexed: 12/26/2022]
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Cardioprotective effects of 3-phosphoinositide-dependent protein kinase-1 on hypoxic injury in cultured neonatal rat cardiomyocytes and myocardium in a rat myocardial infarct model. Biosci Biotechnol Biochem 2012; 76:101-7. [PMID: 22232248 DOI: 10.1271/bbb.110562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
3-Phosphoinositide-dependent protein kinase-1 (PDK1) is involved in numerous cellular responses. In this study, we investigated the protective effects of PDK1 gene expression against hypoxic conditions in cultured rat CMCs (rCMCs) and in a rat myocardial infarction (MI) model using the lentiviral vector (LeV) system. LeV-PDK1 transfer effectively reduced the apoptotic cell death caused by hypoxic injury as compared to LeV-GFP transfer in rCMCs the expression of survival proteins increased in the LeV-PDK1 group, whereas apoptosis signaling decreased in the rCMCs and in infarcted hearts treated with LeV-PDK1. LeV-PDK1 transfer also reduced apoptosis and infarct size and attenuated myocardial wall thinning and ventricular remodeling in a rat MI model. These findings suggest that PDK1 has a protective role in the injured ischemic myocardium via overexpression of the cell survival pathway in CMCs. Hence PDK1 can be used as a treatment strategy for myocardial salvage inin hypoxic injury.
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Sussman MA, Völkers M, Fischer K, Bailey B, Cottage CT, Din S, Gude N, Avitabile D, Alvarez R, Sundararaman B, Quijada P, Mason M, Konstandin MH, Malhowski A, Cheng Z, Khan M, McGregor M. Myocardial AKT: the omnipresent nexus. Physiol Rev 2011; 91:1023-70. [PMID: 21742795 PMCID: PMC3674828 DOI: 10.1152/physrev.00024.2010] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
One of the greatest examples of integrated signal transduction is revealed by examination of effects mediated by AKT kinase in myocardial biology. Positioned at the intersection of multiple afferent and efferent signals, AKT exemplifies a molecular sensing node that coordinates dynamic responses of the cell in literally every aspect of biological responses. The balanced and nuanced nature of homeostatic signaling is particularly essential within the myocardial context, where regulation of survival, energy production, contractility, and response to pathological stress all flow through the nexus of AKT activation or repression. Equally important, the loss of regulated AKT activity is primarily the cause or consequence of pathological conditions leading to remodeling of the heart and eventual decompensation. This review presents an overview compendium of the complex world of myocardial AKT biology gleaned from more than a decade of research. Summarization of the widespread influence that AKT exerts upon myocardial responses leaves no doubt that the participation of AKT in molecular signaling will need to be reckoned with as a seemingly omnipresent regulator of myocardial molecular biological responses.
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Affiliation(s)
- Mark A Sussman
- Department of Biology, San Diego State University, SDSU Heart Institute, San Diego, California 92182, USA.
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Fischer KM, Din S, Gude N, Konstandin MH, Wu W, Quijada P, Sussman MA. Cardiac progenitor cell commitment is inhibited by nuclear Akt expression. Circ Res 2011; 108:960-70. [PMID: 21350213 DOI: 10.1161/circresaha.110.237156] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Stem cell therapies to regenerate damaged cardiac tissue represent a novel approach to treat heart disease. However, the majority of adoptively transferred stem cells delivered to damaged myocardium do not survive long enough to impart protective benefits, resulting in modest functional improvements. Strategies to improve survival and proliferation of stem cells show promise for significantly enhancing cardiac function and regeneration. OBJECTIVE To determine whether injected cardiac progenitor cells (CPCs) genetically modified to overexpress nuclear Akt (CPCeA) increase structural and functional benefits to infarcted myocardium relative to control CPCs. METHODS AND RESULTS CPCeA exhibit significantly increased proliferation and secretion of paracrine factors compared with CPCs. However, CPCeA exhibit impaired capacity for lineage commitment in vitro. Infarcted hearts receiving intramyocardial injection of CPCeA have increased recruitment of endogenous c-kit cells compared with CPCs, but neither population provides long-term functional and structural improvements compared with saline-injected controls. Pharmacological inhibition of Akt alleviated blockade of lineage commitment in CPCeA. CONCLUSIONS Although overexpression of nuclear Akt promotes rapid proliferation and secretion of protective paracrine factors, the inability of CPCeA to undergo lineage commitment hinders their capacity to provide functional or structural benefits to infarcted hearts. Despite enhanced recruitment of endogenous CPCs, lack of functional improvement in CPCeA-treated hearts demonstrates CPC lineage commitment is essential to the regenerative response. Effective stem cell therapies must promote cellular survival and proliferation without inhibiting lineage commitment. Because CPCeA exhibit remarkable proliferative potential, an inducible system mediating nuclear Akt expression could be useful to augment cell therapy approaches.
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14
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STAT3α interacts with nuclear GSK3beta and cytoplasmic RISK pathway and stabilizes rhythm in the anoxic-reoxygenated embryonic heart. Basic Res Cardiol 2011; 106:355-69. [DOI: 10.1007/s00395-011-0152-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 12/23/2010] [Accepted: 01/13/2011] [Indexed: 01/18/2023]
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Cheng Z, Völkers M, Din S, Avitabile D, Khan M, Gude N, Mohsin S, Bo T, Truffa S, Alvarez R, Mason M, Fischer KM, Konstandin MH, Zhang XK, Heller Brown J, Sussman MA. Mitochondrial translocation of Nur77 mediates cardiomyocyte apoptosis. Eur Heart J 2011; 32:2179-88. [PMID: 21228009 DOI: 10.1093/eurheartj/ehq496] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
AIMS The cascade of events leading to compromised mitochondrial integrity in response to stress is mediated by various combinatorial interactions of pro- and anti-apoptotic molecules. Nur77, an immediate early gene that encodes a nuclear orphan receptor, translocates from the nucleus to mitochondria to induce cytochrome c release and apoptosis in cancer cells in response to various pro-apoptotic treatments. However, the role of Nur77 in the cardiac setting is still unclear. The objective of this study is to determine the physiological relevance and pathophysiological importance of Nur77 in cardiomyocytes. METHODS AND RESULTS Myocardial Nur77 is upregulated following cardiomyopathic injury and, while expressed in the postnatal myocardium, declines in level within weeks after birth. Nur77 is localized predominantly in cardiomyocyte nuclei under normal conditions where it is not apoptotic, but translocates to mitochondria in response to oxidative stress both in vitro and in vivo. Mitochondrial localization of Nur77 induces cytochrome c release and typical morphological features of apoptosis, including chromatin condensation and DNA fragmentation. Knockdown of Nur77 rescued hydrogen peroxide-induced cardiomyocyte apoptosis. CONCLUSION Translocation of Nur77 from the nucleus to the mitochondria in cardiomyocytes results in the loss of mitochondrial integrity and subsequent apoptosis in response to ischaemia/reperfusion injury. Our findings identify Nur77 as a novel mediator of cardiomyocyte apoptosis and warrants further investigation of mitochondrial Nur77 translocation as a mechanism to control cell death in the treatment of ischaemic heart diseases.
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Affiliation(s)
- Zhaokang Cheng
- San Diego State Heart Institute, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
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16
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Abstract
Biological actions resulting from phosphoinositide synthesis trigger multiple downstream signalling cascades by recruiting proteins with pleckstrin homology domains, including phosphoinositide-dependent kinase-1 and protein kinase B (also known as Akt). Retrospectively, more attention has been focused on the plasma membrane-associated interactions of these molecules and resulting cytoplasmic target activation. The complex biological activities exerted by Akt activation suggest, however, that more subtle and complex subcellular control mechanisms are involved. This review examines the regulation of Akt activity from the perspective of subcellular compartmentalization and focuses specifically upon the actions of Akt activation downstream from phosphoinositide synthesis that influence cell biology by altering nuclear signalling leading to Pim-1 kinase induction as well as hexokinase phosphorylation that, together with Akt, serves to preserve mitochondrial integrity.
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Affiliation(s)
- Shigeki Miyamoto
- Department of Pharmacology, University of California, La Jolla, San Diego, CA 92093-0636, USA
| | - Marta Rubio
- Department of Biology, SDSU Heart Institute, San Diego State University, NLS 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Mark A. Sussman
- Department of Biology, SDSU Heart Institute, San Diego State University, NLS 426, 5500 Campanile Drive, San Diego, CA 92182, USA
- Corresponding author. Tel: +1 619 594 2983; +1 619 594 2610. E-mail address:
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