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Mitochondrial ATP Synthase Tetramer Disassembly following Blood-Based or del Nido Cardioplegia during Neonatal Cardiac Surgery. THE JOURNAL OF EXTRA-CORPOREAL TECHNOLOGY 2022; 54:203-211. [PMID: 36742212 PMCID: PMC9891487 DOI: 10.1182/ject-203-211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/23/2022] [Indexed: 02/07/2023]
Abstract
Conservation of mitochondrial adenosine triphosphate (ATP) synthase proteins during ischemia is critical to preserve ATP supply and ventricular function. Following myocardial ischemia in adults, higher order ATP synthase tetramer proteins disassemble into simpler monomer units, reducing the efficiency of ATP production. However, it is unknown if myocardial ischemia following the use of cardioplegia results in tetramer disassembly in neonates, and whether it can be mitigated by cardioplegia if it does occur. We investigated myocardial ATP synthase tetramer disassembly in both a neonatal lamb cardiac surgery model and in neonatal children requiring cardiac surgery for the repair of congenital heart disease. Neonatal lambs (Ovis aries) were placed on cardiopulmonary bypass (CPB) and underwent cardioplegic arrest using a single dose of 30 mL/kg antegrade blood-based potassium cardioplegia (n = 4) or a single dose of 30 mL/kg antegrade del Nido cardioplegia (n = 6). Right ventricular biopsies were taken at baseline on CPB (n = 10) and after approximately 60 minutes of cardioplegic arrest before the cross clamp was released (n = 10). Human right ventricular biopsies (n = 3) were taken following 40.0 ± 23.1 minutes of ischemia after a single dose of antegrade blood-based cardioplegia. Protein complexes were separated on clear native gels and the tetramer to monomer ratio quantified. From the neonatal lamb model regardless of the cardioplegia strategy, the tetramer:monomer ratio decreased significantly during ischemia from baseline measurements (.6 ± .2 vs. .5 ± .1; p = .03). The del Nido solution better preserved the tetramer:monomer ratio when compared to the blood-based cardioplegia (Blood .4 ± .1 vs. del Nido .5 ± .1; p = .05). The tetramer:monomer ratio following the use of blood-based cardioplegia in humans aligned with the lamb data (tetramer:monomer .5 ± .2). These initial results suggest that despite cardioprotection, ischemia during neonatal cardiac surgery results in tetramer disassembly which may be limited when using the del Nido solution.
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A reversible mitochondrial complex I thiol switch mediates hypoxic avoidance behavior in C. elegans. Nat Commun 2022; 13:2403. [PMID: 35504873 PMCID: PMC9064984 DOI: 10.1038/s41467-022-30169-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 04/18/2022] [Indexed: 01/28/2023] Open
Abstract
C. elegans react to metabolic distress caused by mismatches in oxygen and energy status via distinct behavioral responses. At the molecular level, these responses are coordinated by under-characterized, redox-sensitive processes, thought to initiate in mitochondria. Complex I of the electron transport chain is a major site of reactive oxygen species (ROS) production and is canonically associated with oxidative damage following hypoxic exposure. Here, we use a combination of optogenetics and CRISPR/Cas9-mediated genome editing to exert spatiotemporal control over ROS production. We demonstrate a photo-locomotory remodeling of avoidance behavior by local ROS production due to the reversible oxidation of a single thiol on the complex I subunit NDUF-2.1. Reversible thiol oxidation at this site is necessary and sufficient for the behavioral response to hypoxia, does not respond to ROS produced at more distal sites, and protects against lethal hypoxic exposure. Molecular modeling suggests that oxidation at this thiol residue alters the ability for NDUF-2.1 to coordinate electron transfer to coenzyme Q by destabilizing the Q-binding pocket, causing decreased complex I activity. Overall, site-specific ROS production regulates behavioral responses and these findings provide a mechanistic target to suppress the detrimental effects of hypoxia.
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Beutner G, Porter GA. Native Gel Electrophoresis and Immunoblotting to Analyze Electron Transport Chain Complexes. Methods Mol Biol 2021; 2276:103-112. [PMID: 34060035 DOI: 10.1007/978-1-0716-1266-8_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Native electrophoresis is a powerful tool to analyze the mitochondrial electron transport chain complexes (Cx) I-V and their assembly into supercomplexes. Valuable information regarding the composition and bioenergetic regulation in physiological and pathological conditions can be obtained. This chapter compares different types of native electrophoresis to analyze mitochondrial supercomplexes.
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Affiliation(s)
- Gisela Beutner
- Department of Pediatrics-Division Cardiology, University of Rochester, Rochester, NY, USA
| | - George A Porter
- Departments of Pediatrics-Division Cardiology, Pharmacology and Physiology, and Medicine (Aab Cardiovascular Research Institute), University of Rochester, Rochester, NY, USA.
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Ma Y, Zhang Y, Xiao Y, Xiao F. Increased Mitochondrial Fragmentation Mediated by Dynamin-Related Protein 1 Contributes to Hexavalent Chromium-Induced Mitochondrial Respiratory Chain Complex I-Dependent Cytotoxicity. TOXICS 2020; 8:E50. [PMID: 32751088 PMCID: PMC7560259 DOI: 10.3390/toxics8030050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 05/17/2023]
Abstract
Hexavalent chromium (Cr(VI)) pollution is a severe public health problem in the world. Although it is believed that mitochondrial fragmentation is a common phenomenon in apoptosis, whether excessive fission is crucial for apoptosis remains controversial. We previously confirmed that Cr(VI) mainly targeted mitochondrial respiratory chain complex I (MRCC I) to induce reactive oxygen species (ROS)-mediated apoptosis, but the related mechanism was unclear. In this study, we found Cr(VI) targeted MRCC I to induce ROS accumulation and triggered mitochondria-related cytotoxicity. Cr(VI)-induced cytotoxicity was alleviated by pretreatment of Glutamate/malate (Glu/Mal; MRCC I substrates), and was aggravated by cotreatment of rotenone (ROT; MRCC I inhibitor). Cr(VI) induced excessive mitochondrial fragmentation and mitochondrial dynamin-related protein 1 (Drp1) translocation, the application of Drp1-siRNA alleviated Cr(VI)-induced apoptosis. The cytotoxicity in the Drp1-si plus Cr(VI) treatment group was alleviated by the application of Glu/Mal, and was aggravated by the application of ROT. Drp1 siRNA promoted the inhibition of Glu/Mal on Cr(VI)-induced cytotoxicity, and alleviated the aggravation of ROT on Cr(VI)-induced cytotoxicity. Taken together, Cr(VI)-induced Drp1 modulation was dependent on MRCC I inhibition-mediated ROS production, and Drp1-mediated mitochondrial fragmentation contributed to Cr(VI)-induced MRCC I-dependent cytotoxicity, which provided the experimental basis for further elucidating Cr(VI)-induced cytotoxicity.
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Affiliation(s)
| | | | | | - Fang Xiao
- Department of Health Toxicology, Xiangya School of Public Health, Central South University, Changsha 410078, China; (Y.M.); (Y.Z.); (Y.X.)
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Ait-Aissa K, Blaszak SC, Beutner G, Tsaih SW, Morgan G, Santos JH, Flister MJ, Joyce DL, Camara AKS, Gutterman DD, Donato AJ, Porter GA, Beyer AM. Mitochondrial Oxidative Phosphorylation defect in the Heart of Subjects with Coronary Artery Disease. Sci Rep 2019; 9:7623. [PMID: 31110224 PMCID: PMC6527853 DOI: 10.1038/s41598-019-43761-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/06/2018] [Indexed: 12/21/2022] Open
Abstract
Coronary artery disease (CAD) is a leading cause of death worldwide and frequently associated with mitochondrial dysfunction. Detailed understanding of abnormalities in mitochondrial function that occur in patients with CAD is lacking. We evaluated mitochondrial damage, energy production, and mitochondrial complex activity in human non-CAD and CAD hearts. Fresh and frozen human heart tissue was used. Cell lysate or mitochondria were isolated using standard techniques. Mitochondrial DNA (mtDNA), NAD + and ATP levels, and mitochondrial oxidative phosphorylation capacity were evaluated. Proteins critical to the regulation of mitochondrial metabolism and function were also evaluated in tissue lysates. PCR analysis revealed an increase in mtDNA lesions and the frequency of mitochondrial common deletion, both established markers for impaired mitochondrial integrity in CAD compared to non-CAD patient samples. NAD+ and ATP levels were significantly decreased in CAD subjects compared to Non-CAD (NAD+ fold change: non-CAD 1.00 ± 0.17 vs. CAD 0.32 ± 0.12* and ATP fold change: non-CAD 1.00 ± 0.294 vs. CAD 0.01 ± 0.001*; N = 15, P < 0.005). We observed decreased respiration control index in CAD tissue and decreased activity of complexes I, II, and III. Expression of ETC complex subunits and respirasome formation were increased; however, elevations in the de-active form of complex I were observed in CAD. We observed a corresponding increase in glycolytic flux, indicated by a rise in pyruvate kinase and lactate dehydrogenase activity, indicating a compensatory increase in glycolysis for cellular energetics. Together, these results indicate a shift in mitochondrial metabolism from oxidative phosphorylation to glycolysis in human hearts subjects with CAD.
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Affiliation(s)
- Karima Ait-Aissa
- Cardiovascular Center, Department of Medicine, Med College of Wisconsin, Milwaukee, WI, USA.
| | - Scott C Blaszak
- Cardiovascular Center, Department of Medicine, Med College of Wisconsin, Milwaukee, WI, USA
| | - Gisela Beutner
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Shirng-Wern Tsaih
- Department of Physiology, Med College of Wisconsin, Milwaukee, WI, USA
| | - Garrett Morgan
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - Janine H Santos
- Genome Integrity and Structural Biology Laboratory, NIHEHS, Raleigh-Durham, NC, USA
| | - Michael J Flister
- Department of Physiology, Med College of Wisconsin, Milwaukee, WI, USA
| | - David L Joyce
- Department of Surgery, Med College of Wisconsin, Milwaukee, WI, USA
| | - Amadou K S Camara
- Department of Physiology, Med College of Wisconsin, Milwaukee, WI, USA.,Department of Anesthesiology, Med College of Wisconsin, Milwaukee, WI, USA
| | - David D Gutterman
- Cardiovascular Center, Department of Medicine, Med College of Wisconsin, Milwaukee, WI, USA
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,VA Medical Center-Salt Lake City, GRECC, Salt Lake City, Utah, USA
| | - George A Porter
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA.,Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA.,Department of Medicine (Aab Cardiovascular Research Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Andreas M Beyer
- Cardiovascular Center, Department of Medicine, Med College of Wisconsin, Milwaukee, WI, USA. .,Department of Physiology, Med College of Wisconsin, Milwaukee, WI, USA.
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Beutner G, Alanzalon RE, Porter GA. Cyclophilin D regulates the dynamic assembly of mitochondrial ATP synthase into synthasomes. Sci Rep 2017; 7:14488. [PMID: 29101324 PMCID: PMC5670235 DOI: 10.1038/s41598-017-14795-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/16/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial electron transport is essential for oxidative phosphorylation (OXPHOS). Electron transport chain (ETC) activity generates an electrochemical gradient that is used by the ATP synthase to make ATP. ATP synthase is organized into supramolecular units called synthasomes that increase the efficiency of ATP production, while within ATP synthase is the cyclophilin D (CypD) regulated mitochondrial permeability transition pore (PTP). We investigated whether synthasomes are dynamic structures that respond to metabolic demands and whether CypD regulates this dynamic. Isolated heart mitochondria from wild-type (WT) and CypD knockout (KO) mice were treated to either stimulate OXPHOS or open the PTP. The presence and dynamics of mitochondrial synthasomes were investigated by native electrophoresis, immunoprecipitation, and sucrose density centrifugation. We show that stimulation of OXPHOS, inhibition of the PTP, or deletion of CypD increased high order synthasome assembly. In contrast, OXPHOS inhibition or PTP opening increased synthasome disassembly in WT, but not in CypD KO heart mitochondria. CypD activity also correlated with synthasome assembly in other tissues, such as liver and brain. We conclude that CypD not only regulates the PTP, but also regulates the dynamics of synthasome assembly depending on the bioenergetic state of the mitochondria.
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Affiliation(s)
- Gisela Beutner
- Department of Pediatrics (Cardiology), University of Rochester, Rochester, New York, 14642, United States
| | - Ryan E Alanzalon
- Department of Pediatrics (Cardiology), University of Rochester, Rochester, New York, 14642, United States
| | - George A Porter
- Department of Pediatrics (Cardiology), University of Rochester, Rochester, New York, 14642, United States.
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York, 14642, United States.
- Department of Medicine (Aab Cardiovascular Research Institute), University of Rochester, Rochester, New York, 14642, United States.
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