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Ježek P, Jabůrek M, Holendová B, Engstová H, Dlasková A. Mitochondrial Cristae Morphology Reflecting Metabolism, Superoxide Formation, Redox Homeostasis, and Pathology. Antioxid Redox Signal 2023; 39:635-683. [PMID: 36793196 PMCID: PMC10615093 DOI: 10.1089/ars.2022.0173] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023]
Abstract
Significance: Mitochondrial (mt) reticulum network in the cell possesses amazing ultramorphology of parallel lamellar cristae, formed by the invaginated inner mitochondrial membrane. Its non-invaginated part, the inner boundary membrane (IBM) forms a cylindrical sandwich with the outer mitochondrial membrane (OMM). Crista membranes (CMs) meet IBM at crista junctions (CJs) of mt cristae organizing system (MICOS) complexes connected to OMM sorting and assembly machinery (SAM). Cristae dimensions, shape, and CJs have characteristic patterns for different metabolic regimes, physiological and pathological situations. Recent Advances: Cristae-shaping proteins were characterized, namely rows of ATP-synthase dimers forming the crista lamella edges, MICOS subunits, optic atrophy 1 (OPA1) isoforms and mitochondrial genome maintenance 1 (MGM1) filaments, prohibitins, and others. Detailed cristae ultramorphology changes were imaged by focused-ion beam/scanning electron microscopy. Dynamics of crista lamellae and mobile CJs were demonstrated by nanoscopy in living cells. With tBID-induced apoptosis a single entirely fused cristae reticulum was observed in a mitochondrial spheroid. Critical Issues: The mobility and composition of MICOS, OPA1, and ATP-synthase dimeric rows regulated by post-translational modifications might be exclusively responsible for cristae morphology changes, but ion fluxes across CM and resulting osmotic forces might be also involved. Inevitably, cristae ultramorphology should reflect also mitochondrial redox homeostasis, but details are unknown. Disordered cristae typically reflect higher superoxide formation. Future Directions: To link redox homeostasis to cristae ultramorphology and define markers, recent progress will help in uncovering mechanisms involved in proton-coupled electron transfer via the respiratory chain and in regulation of cristae architecture, leading to structural determination of superoxide formation sites and cristae ultramorphology changes in diseases. Antioxid. Redox Signal. 39, 635-683.
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Affiliation(s)
- Petr Ježek
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Martin Jabůrek
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Blanka Holendová
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Hana Engstová
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Andrea Dlasková
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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2
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Watson MA, Brar H, Gibbs ET, Wong HS, Dighe PA, McKibben B, Riedmaier S, Siu A, Polakowski JS, Segreti JA, Liu X, Chung S, Pliushchev YM, Gesmundo N, Wang Z, Vortherms TA, Brand MD. Suppression of superoxide/hydrogen peroxide production at mitochondrial site I Q decreases fat accumulation, improves glucose tolerance and normalizes fasting insulin concentration in mice fed a high-fat diet. Free Radic Biol Med 2023; 204:276-286. [PMID: 37217089 DOI: 10.1016/j.freeradbiomed.2023.05.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/04/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
We developed S1QEL1.719, a novel bioavailable S1QEL (suppressor of site IQ electron leak). S1QEL1.719 prevented superoxide/hydrogen peroxide production at site IQ of mitochondrial complex I in vitro. The free concentration giving half-maximal suppression (IC50) was 52 nM. Even at 50-fold higher concentrations S1QEL1.719 did not inhibit superoxide/hydrogen peroxide production from other sites. The IC50 for inhibition of complex I electron flow was 500-fold higher than the IC50 for suppression of superoxide/hydrogen peroxide production from site IQ. S1QEL1.719 was used to test the metabolic effects of suppressing superoxide/hydrogen peroxide production from site IQin vivo. C57BL/6J male mice fed a high-fat chow for one, two or eight weeks had increased body fat, decreased glucose tolerance, and increased fasting insulin concentrations, classic symptoms of metabolic syndrome. Daily prophylactic or therapeutic oral treatment of high-fat-fed animals with S1QEL1.719 decreased fat accumulation, strongly protected against decreased glucose tolerance and prevented or reversed the increase in fasting insulin level. Free exposures in plasma and liver at Cmax were 1-4 fold the IC50 for suppression of superoxide/hydrogen peroxide production at site IQ and substantially below levels that inhibit electron flow through complex I. These results show that the production of superoxide/hydrogen peroxide from mitochondrial site IQin vivo is necessary for the induction and maintenance of glucose intolerance caused by a high-fat diet in mice. They raise the possibility that oral administration of S1QELs may be beneficial in metabolic syndrome.
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Affiliation(s)
- Mark A Watson
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | - Harmanmeet Brar
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | - Edwin T Gibbs
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | - Hoi-Shan Wong
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | - Pratiksha A Dighe
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | - Bryan McKibben
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | | | - Amy Siu
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | | | - Jason A Segreti
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | - Xiaoqin Liu
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | - SeungWon Chung
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | | | - Nathan Gesmundo
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | - Zhi Wang
- AbbVie Inc, 1 North Waukegan Road, North Chicago, IL, 60064, USA.
| | | | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
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3
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Castejon-Vega B, Cordero MD, Sanz A. How the Disruption of Mitochondrial Redox Signalling Contributes to Ageing. Antioxidants (Basel) 2023; 12:antiox12040831. [PMID: 37107206 PMCID: PMC10135186 DOI: 10.3390/antiox12040831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/16/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
In the past, mitochondrial reactive oxygen species (mtROS) were considered a byproduct of cellular metabolism. Due to the capacity of mtROS to cause oxidative damage, they were proposed as the main drivers of ageing and age-related diseases. Today, we know that mtROS are cellular messengers instrumental in maintaining cellular homeostasis. As cellular messengers, they are produced in specific places at specific times, and the intensity and duration of the ROS signal determine the downstream effects of mitochondrial redox signalling. We do not know yet all the processes for which mtROS are important, but we have learnt that they are essential in decisions that affect cellular differentiation, proliferation and survival. On top of causing damage due to their capacity to oxidize cellular components, mtROS contribute to the onset of degenerative diseases when redox signalling becomes dysregulated. Here, we review the best-characterized signalling pathways in which mtROS participate and those pathological processes in which they are involved. We focus on how mtROS signalling is altered during ageing and discuss whether the accumulation of damaged mitochondria without signalling capacity is a cause or a consequence of ageing.
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Gibbs ET, Lerner CA, Watson MA, Wong HS, Gerencser AA, Brand MD. Site IQ in mitochondrial complex I generates S1QEL-sensitive superoxide/hydrogen peroxide in both the reverse and forward reactions. Biochem J 2023; 480:363-384. [PMID: 36862427 DOI: 10.1042/bcj20220611] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/03/2023]
Abstract
Superoxide/hydrogen peroxide production by site IQ in complex I of the electron transport chain is conventionally assayed during reverse electron transport (RET) from ubiquinol to NAD. However, S1QELs (specific suppressors of superoxide/hydrogen peroxide production by site IQ) have potent effects in cells and in vivo during presumed forward electron transport (FET). Therefore, we tested whether site IQ generates S1QEL-sensitive superoxide/hydrogen peroxide during FET (site IQf), or alternatively, whether RET and associated S1QEL-sensitive superoxide/hydrogen peroxide production (site IQr) occurs in cells under normal conditions. We introduce an assay to determine if electron flow through complex I is thermodynamically forward or reverse: on blocking electron flow through complex I, the endogenous matrix NAD pool will become more reduced if flow before the challenge was forward, but more oxidised if flow was reverse. Using this assay we show in the model system of isolated rat skeletal muscle mitochondria that superoxide/hydrogen peroxide production by site IQ can be equally great whether RET or FET is running. We show that sites IQr and IQf are equally sensitive to S1QELs, and to rotenone and piericidin A, inhibitors that block the Q-site of complex I. We exclude the possibility that some sub-fraction of the mitochondrial population running site IQr during FET is responsible for S1QEL-sensitive superoxide/hydrogen peroxide production by site IQ. Finally, we show that superoxide/hydrogen peroxide production by site IQ in cells occurs during FET, and is S1QEL-sensitive.
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Affiliation(s)
- Edwin T Gibbs
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
| | - Chad A Lerner
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
| | - Mark A Watson
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
| | - Hoi-Shan Wong
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
| | - Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, U.S.A
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Wang K, Hirschenson J, Moore A, Mailloux RJ. Conditions Conducive to the Glutathionylation of Complex I Subunit NDUFS1 Augment ROS Production following the Oxidation of Ubiquinone Linked Substrates, Glycerol-3-Phosphate and Proline. Antioxidants (Basel) 2022; 11:2043. [PMID: 36290766 PMCID: PMC9598259 DOI: 10.3390/antiox11102043] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 08/15/2023] Open
Abstract
Mitochondrial complex I can produce large quantities of reactive oxygen species (ROS) by reverse electron transfer (RET) from the ubiquinone (UQ) pool. Glutathionylation of complex I does induce increased mitochondrial superoxide/hydrogen peroxide (O2●-/H2O2) production, but the source of this ROS has not been identified. Here, we interrogated the glutathionylation of complex I subunit NDUFS1 and examined if its modification can result in increased ROS production during RET from the UQ pool. We also assessed glycerol-3-phosphate dehydrogenase (GPD) and proline dehydrogenase (PRODH) glutathionylation since both flavoproteins have measurable rates for ROS production as well. Induction of glutathionylation with disulfiram induced a significant increase in O2●-/H2O2 production during glycerol-3-phosphate (G3P) and proline (Pro) oxidation. Treatment of mitochondria with inhibitors for complex I (rotenone and S1QEL), complex III (myxothiazol and S3QEL), glycerol-3-phosphate dehydrogenase (iGP), and proline dehydrogenase (TFA) confirmed that the sites for this increase were complexes I and III, respectively. Treatment of liver mitochondria with disulfiram (50-1000 nM) did not induce GPD or PRODH glutathionylation, nor did it affect their activities, even though disulfiram dose-dependently increased the total number of protein glutathione mixed disulfides (PSSG). Immunocapture of complex I showed disulfiram incubations resulted in the modification of NDUFS1 subunit in complex I. Glutathionylation could be reversed by reducing agents, restoring the deglutathionylated state of NDUFS1 and the activity of the complex. Reduction of glutathionyl moieties in complex I also significantly decreased ROS production by RET from GPD and PRODH. Overall, these findings demonstrate that the modification of NDUFS1 can result in increased ROS production during RET from the UQ pool, which has implications for understanding the relationship between mitochondrial glutathionylation reactions and induction of oxidative distress in several pathologies.
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Affiliation(s)
| | | | | | - Ryan J. Mailloux
- The School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Montreal, QC H9X 3V9, Canada
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Fang J, Zhang Y, Gerencser AA, Brand MD. Effects of sugars, fatty acids and amino acids on cytosolic and mitochondrial hydrogen peroxide release from liver cells. Free Radic Biol Med 2022; 188:92-102. [PMID: 35716827 PMCID: PMC9363135 DOI: 10.1016/j.freeradbiomed.2022.06.225] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/31/2022] [Accepted: 06/12/2022] [Indexed: 11/24/2022]
Abstract
The rates of formation of superoxide and hydrogen peroxide at different electron-donating sites in isolated mitochondria are critically dependent on the substrates that are added, through their effects on the reduction level of each site and the components of the protonmotive force. However, in intact cells the acute effects of added substrates on different sites of cytosolic and mitochondrial hydrogen peroxide production are unclear. Here we tested the effects of substrate addition on cytosolic and mitochondrial hydrogen peroxide release from intact AML12 liver cells. In 30-min starved cells replete with endogenous substrates, addition of glucose, fructose, palmitate, alanine, leucine or glutamine had no effect on the rate or origin of cellular hydrogen peroxide release. However, following 150-min starvation of the cells to deplete endogenous glycogen (and other substrates), cellular hydrogen peroxide production, particularly from NADPH oxidases (NOXs), was decreased, GSH/GSSH ratio increased, and antioxidant gene expression was unchanged. Addition of glucose or glutamine (but not the other substrates) increased hydrogen peroxide release. There were similar relative increases from each of the three major sites of production: mitochondrial sites IQ and IIIQo, and cytosolic NOXs. Glucose supplementation also restored ATP production and mitochondrial NAD reduction level, suggesting that the increased rates of hydrogen peroxide release from the mitochondrial sites were driven by increases in the protonmotive force and the degree of reduction of the electron transport chain. Long-term (24 h) glucose or glutamine deprivation also diminished hydrogen peroxide release rate, ATP production rate and (for glucose deprivation) NAD reduction level. We conclude that the rates of superoxide and hydrogen peroxide production from mitochondrial sites in liver cells are insensitive to extra added substrates when endogenous substrates are not depleted, but these rates are decreased when endogenous substrates are lowered by 150 min of starvation, and can be enhanced by restoring glucose or glutamine supply through improvements in mitochondrial energetic state.
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Affiliation(s)
- Jingqi Fang
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA, 94945, USA.
| | - Yini Zhang
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA, 94945, USA.
| | - Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA, 94945, USA.
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA, 94945, USA.
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Curtabbi A, Enríquez JA. The ins and outs of the flavin mononucleotide cofactor of respiratory complex I. IUBMB Life 2022; 74:629-644. [PMID: 35166025 DOI: 10.1002/iub.2600] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/12/2022]
Abstract
The flavin mononucleotide (FMN) cofactor of respiratory complex I occupies a key position in the electron transport chain. Here, the electrons coming from NADH start the sequence of oxidoreduction reactions, which drives the generation of the proton-motive force necessary for ATP synthesis. The overall architecture and the general catalytic proprieties of the FMN site are mostly well established. However, several aspects regarding the complex I flavin cofactor are still unknown. For example, the flavin binding to the N-module, the NADH-oxidizing portion of complex I, lacks a molecular description. The dissociation of FMN from the enzyme is beginning to emerge as an important regulatory mechanism of complex I activity and ROS production. Finally, how mitochondria import and metabolize FMN is still uncertain. This review summarizes the current knowledge on complex I flavin cofactor and discusses the open questions for future research.
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Affiliation(s)
- Andrea Curtabbi
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain.,Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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Ragab EM, El Gamal DM, Mohamed TM, Khamis AA. Study of the inhibitory effects of chrysin and its nanoparticles on mitochondrial complex II subunit activities in normal mouse liver and human fibroblasts. J Genet Eng Biotechnol 2022; 20:15. [PMID: 35089446 PMCID: PMC8795958 DOI: 10.1186/s43141-021-00286-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Mitochondrial complex ΙΙ has a unique biological role owing to its participation in both the citric acid cycle and the electron transport chain. Our goal was to evaluate the succinate dehydrogenase and ubiquinone oxidoreductase activity of mitochondrial complex II in the presence of chrysin and chrysin-chitosan nanoparticles. Chrysin chitosan nanoparticles were synthesized and characterized using ultraviolet spectroscopy, Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, drug release, and zeta potential. The binding affinity of chrysin to complex II subunits was assessed by molecular docking. The IC50 values were measured in a suspension of mouse mitochondria, and the inhibitory effect of chrysin and chrysin chitosan nanoparticles on mitochondrial complex ΙΙ was determined. RESULTS The free energy of binding between chrysin and complex ΙΙ subunits A, B, C, and D was -4.9, -5, -8.2, and -8.4 kcal/mol, respectively. The characteristic peak of chrysin was confirmed at 348 nm. The chrysin chitosan nanoparticles contained characteristic bands of both chrysin and chitosan. The crystalline nature of chrysin chitosan nanoparticles was confirmed by X-ray powder diffraction measurements showing the characteristic Bragg peaks of (11.2°), (32.2°), (19.6°), (27.6°), and (31.96°). Transmission and scanning electron microscopy revealed their spherical shape and an average particle size of 49.7 ± 3.02 nm. Chrysin chitosan nanoparticles showed a burst release within the initial 2 h followed by a steady release at 8 h. Their zeta potential was positive, between +35.5 and +80 mV. The IC50 of chrysin, chitosan nanoparticles, chrysin chitosan nanoparticles, and 5-fluorouracil was 34.66, 184.1, 12.2, and 0.05 μg/mL, respectively, in adult mice liver and 129, 311, 156, and 8.07 μg/mL, respectively, in normal human fibroblasts. When comparing the inhibitory effects on complex ΙΙ activity, application of the IC50 of chrysin, chitosan nanoparticles, chrysin chitosan nanoparticles, and 5-fluorouracil resulted in 40.14%, 90.9%, 86.7%, and 89% decreases in SDH activity and 70.09%, 86.74%, 60.8%, and 80.23% decreases in ubiquinone oxidoreductase activity in normal adult mice, but 80.9%, 89.06%, and 90% significant decreases in SDH activity, and 90%, 85%, and 95% decreases in ubiquinone reductase after treatment with chrysin, chrysin chitosan nanoparticles, and 5-fluorouracil, in normal human fibroblasts, respectively. CONCLUSIONS Chrysin and CCNPs exhibit potent inhibitory effects on SDH activity ubiquinone oxidoreductase activity.
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Affiliation(s)
- Eman M Ragab
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Doaa M El Gamal
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Tarek M Mohamed
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Abeer A Khamis
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
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Mookerjee SA, Gerencser AA, Watson MA, Brand MD. Controlled power: how biology manages succinate-driven energy release. Biochem Soc Trans 2021; 49:2929-2939. [PMID: 34882231 PMCID: PMC8786295 DOI: 10.1042/bst20211032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022]
Abstract
Oxidation of succinate by mitochondria can generate a higher protonmotive force (pmf) than can oxidation of NADH-linked substrates. Fundamentally, this is because of differences in redox potentials and gearing. Biology adds kinetic constraints that tune the oxidation of NADH and succinate to ensure that the resulting mitochondrial pmf is suitable for meeting cellular needs without triggering pathology. Tuning within an optimal range is used, for example, to shift ATP consumption between different consumers. Conditions that overcome these constraints and allow succinate oxidation to drive pmf too high can cause pathological generation of reactive oxygen species. We discuss the thermodynamic properties that allow succinate oxidation to drive pmf higher than NADH oxidation, and discuss the evidence for kinetic tuning of ATP production and for pathologies resulting from substantial succinate oxidation in vivo.
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Affiliation(s)
- Shona A. Mookerjee
- Department of Biological and Pharmaceutical Sciences, Touro University California College of Pharmacy, Vallejo, CA, U.S.A
- Buck Institute for Research on Aging, Novato, CA, U.S.A
| | | | | | - Martin D. Brand
- Department of Biological and Pharmaceutical Sciences, Touro University California College of Pharmacy, Vallejo, CA, U.S.A
- Buck Institute for Research on Aging, Novato, CA, U.S.A
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10
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Therapeutic targeting of the hypoxic tumour microenvironment. Nat Rev Clin Oncol 2021; 18:751-772. [PMID: 34326502 DOI: 10.1038/s41571-021-00539-4] [Citation(s) in RCA: 179] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2021] [Indexed: 02/07/2023]
Abstract
Hypoxia is prevalent in human tumours and contributes to microenvironments that shape cancer evolution and adversely affect therapeutic outcomes. Historically, two different tumour microenvironment (TME) research communities have been discernible. One has focused on physicochemical gradients of oxygen, pH and nutrients in the tumour interstitium, motivated in part by the barrier that hypoxia poses to effective radiotherapy. The other has focused on cellular interactions involving tumour and non-tumour cells within the TME. Over the past decade, strong links have been established between these two themes, providing new insights into fundamental aspects of tumour biology and presenting new strategies for addressing the effects of hypoxia and other microenvironmental features that arise from the inefficient microvascular system in solid tumours. This Review provides a perspective on advances at the interface between these two aspects of the TME, with a focus on translational therapeutic opportunities relating to the elimination and/or exploitation of tumour hypoxia.
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11
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Priming, Triggering, Adaptation and Senescence (PTAS): A Hypothesis for a Common Damage Mechanism of Steatohepatitis. Int J Mol Sci 2021; 22:ijms222212545. [PMID: 34830427 PMCID: PMC8624051 DOI: 10.3390/ijms222212545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/17/2022] Open
Abstract
Understanding the pathomechanism of steatohepatitis (SH) is hampered by the difficulty of distinguishing between causes and consequences, by the broad spectrum of aetiologies that can produce the phenotype, and by the long time-span during which SH develops, often without clinical symptoms. We propose that SH develops in four phases with transitions: (i) priming lowers stress defence; (ii) triggering leads to acute damage; (iii) adaptation, possibly associated with cellular senescence, mitigates tissue damage, leads to the phenotype, and preserves liver function at a lower level; (iv) finally, senescence prevents neoplastic transformation but favours fibrosis (cirrhosis) and inflammation and further reduction in liver function. Escape from senescence eventually leads to hepatocellular carcinoma. This hypothesis for a pathomechanism of SH is supported by clinical and experimental observations. It allows organizing the various findings to uncover remaining gaps in our knowledge and, finally, to provide possible diagnostic and intervention strategies for each stage of SH development.
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Herb M, Gluschko A, Schramm M. Reactive Oxygen Species: Not Omnipresent but Important in Many Locations. Front Cell Dev Biol 2021; 9:716406. [PMID: 34557488 PMCID: PMC8452931 DOI: 10.3389/fcell.2021.716406] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/19/2021] [Indexed: 01/08/2023] Open
Abstract
Reactive oxygen species (ROS), such as the superoxide anion or hydrogen peroxide, have been established over decades of research as, on the one hand, important and versatile molecules involved in a plethora of homeostatic processes and, on the other hand, as inducers of damage, pathologies and diseases. Which effects ROS induce, strongly depends on the cell type and the source, amount, duration and location of ROS production. Similar to cellular pH and calcium levels, which are both strictly regulated and only altered by the cell when necessary, the redox balance of the cell is also tightly regulated, not only on the level of the whole cell but in every cellular compartment. However, a still widespread view present in the scientific community is that the location of ROS production is of no major importance and that ROS randomly diffuse from their cellular source of production throughout the whole cell and hit their redox-sensitive targets when passing by. Yet, evidence is growing that cells regulate ROS production and therefore their redox balance by strictly controlling ROS source activation as well as localization, amount and duration of ROS production. Hopefully, future studies in the field of redox biology will consider these factors and analyze cellular ROS more specifically in order to revise the view of ROS as freely flowing through the cell.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Alexander Gluschko
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
| | - Michael Schramm
- Institute for Medical Microbiology, Immunology and Hygiene, Cologne, Germany
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Yan LJ. NADH/NAD + Redox Imbalance and Diabetic Kidney Disease. Biomolecules 2021; 11:biom11050730. [PMID: 34068842 PMCID: PMC8153586 DOI: 10.3390/biom11050730] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/11/2022] Open
Abstract
Diabetic kidney disease (DKD) is a common and severe complication of diabetes mellitus. If left untreated, DKD can advance to end stage renal disease that requires either dialysis or kidney replacement. While numerous mechanisms underlie the pathogenesis of DKD, oxidative stress driven by NADH/NAD+ redox imbalance and mitochondrial dysfunction have been thought to be the major pathophysiological mechanism of DKD. In this review, the pathways that increase NADH generation and those that decrease NAD+ levels are overviewed. This is followed by discussion of the consequences of NADH/NAD+ redox imbalance including disruption of mitochondrial homeostasis and function. Approaches that can be applied to counteract DKD are then discussed, which include mitochondria-targeted antioxidants and mimetics of superoxide dismutase, caloric restriction, plant/herbal extracts or their isolated compounds. Finally, the review ends by pointing out that future studies are needed to dissect the role of each pathway involved in NADH-NAD+ metabolism so that novel strategies to restore NADH/NAD+ redox balance in the diabetic kidney could be designed to combat DKD.
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Affiliation(s)
- Liang-Jun Yan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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Brand MD. Riding the tiger - physiological and pathological effects of superoxide and hydrogen peroxide generated in the mitochondrial matrix. Crit Rev Biochem Mol Biol 2020; 55:592-661. [PMID: 33148057 DOI: 10.1080/10409238.2020.1828258] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Elevated mitochondrial matrix superoxide and/or hydrogen peroxide concentrations drive a wide range of physiological responses and pathologies. Concentrations of superoxide and hydrogen peroxide in the mitochondrial matrix are set mainly by rates of production, the activities of superoxide dismutase-2 (SOD2) and peroxiredoxin-3 (PRDX3), and by diffusion of hydrogen peroxide to the cytosol. These considerations can be used to generate criteria for assessing whether changes in matrix superoxide or hydrogen peroxide are both necessary and sufficient to drive redox signaling and pathology: is a phenotype affected by suppressing superoxide and hydrogen peroxide production; by manipulating the levels of SOD2, PRDX3 or mitochondria-targeted catalase; and by adding mitochondria-targeted SOD/catalase mimetics or mitochondria-targeted antioxidants? Is the pathology associated with variants in SOD2 and PRDX3 genes? Filtering the large literature on mitochondrial redox signaling using these criteria highlights considerable evidence that mitochondrial superoxide and hydrogen peroxide drive physiological responses involved in cellular stress management, including apoptosis, autophagy, propagation of endoplasmic reticulum stress, cellular senescence, HIF1α signaling, and immune responses. They also affect cell proliferation, migration, differentiation, and the cell cycle. Filtering the huge literature on pathologies highlights strong experimental evidence that 30-40 pathologies may be driven by mitochondrial matrix superoxide or hydrogen peroxide. These can be grouped into overlapping and interacting categories: metabolic, cardiovascular, inflammatory, and neurological diseases; cancer; ischemia/reperfusion injury; aging and its diseases; external insults, and genetic diseases. Understanding the involvement of mitochondrial matrix superoxide and hydrogen peroxide concentrations in these diseases can facilitate the rational development of appropriate therapies.
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