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Zhang J, Lv W, Zhang G, Zeng M, Cao W, Su J, Cao K, Liu J. Nuclear Factor Erythroid 2 Related Factor 2 and Mitochondria Form a Mutually Regulating Circuit in the Prevention and Treatment of Metabolic Syndrome. Antioxid Redox Signal 2024. [PMID: 38183629 DOI: 10.1089/ars.2023.0339] [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] [Indexed: 01/08/2024]
Abstract
Significance: Metabolic syndrome (MetS) has become a major global public health problem and there is an urgent need to elucidate its pathogenesis and find more effective targets and modalities for intervention. Recent Advances: Oxidative stress and inflammation are two of the major causes of MetS-related symptoms such as insulin resistance and obesity. Nuclear factor erythroid 2 related factor 2 (Nrf2) is one of the important systems responding to oxidative stress and inflammation. As cells undergo stress, cysteines within Kelch-like ECH-associated protein 1 (Keap1) are oxidized or electrophilically modified, allowing Nrf2 to escape ubiquitination and be translocated from the cytoplasm to the nucleus, facilitating the initiation of the antioxidant transcriptional program. Meanwhile, a growing body of evidence points out a specific modulation of mitochondrial homeostasis by Nrf2. After nuclear translocation, Nrf2 activates downstream genes involved in various aspects of mitochondrial homeostasis, including mitochondrial biogenesis and dynamics, mitophagy, aerobic respiration, and energy metabolism. In turn, mitochondria reciprocally activate Nrf2 by releasing reactive oxygen species and regulating antioxidant enzymes. Critical Issues: In this review, we first summarize the interactions between Nrf2 and mitochondria in the modulation of oxidative stress and inflammation to ameliorate MetS, then propose that Nrf2 and mitochondria form a mutually regulating circuit critical to maintaining homeostasis during MetS. Future Directions: Targeting the Nrf2-mitochondrial circuit may be a promising strategy to ameliorate MetS, such as obesity, diabetes, and cardiovascular diseases.
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Affiliation(s)
- Jiawei Zhang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Weiqiang Lv
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Guanfei Zhang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Mengqi Zeng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Wenli Cao
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiacan Su
- Department of Orthopedics Trauma, Shanghai Changhai Hospital, Naval Military Medical University, Shanghai, China
| | - Ke Cao
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, China
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Ueda N. A Rheostat of Ceramide and Sphingosine-1-Phosphate as a Determinant of Oxidative Stress-Mediated Kidney Injury. Int J Mol Sci 2022; 23:ijms23074010. [PMID: 35409370 PMCID: PMC9000186 DOI: 10.3390/ijms23074010] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/29/2022] [Accepted: 03/29/2022] [Indexed: 02/06/2023] Open
Abstract
Reactive oxygen species (ROS) modulate sphingolipid metabolism, including enzymes that generate ceramide and sphingosine-1-phosphate (S1P), and a ROS-antioxidant rheostat determines the metabolism of ceramide-S1P. ROS induce ceramide production by activating ceramide-producing enzymes, leading to apoptosis, while they inhibit S1P production, which promotes survival by suppressing sphingosine kinases (SphKs). A ceramide-S1P rheostat regulates ROS-induced mitochondrial dysfunction, apoptotic/anti-apoptotic Bcl-2 family proteins and signaling pathways, leading to apoptosis, survival, cell proliferation, inflammation and fibrosis in the kidney. Ceramide inhibits the mitochondrial respiration chain and induces ceramide channel formation and the closure of voltage-dependent anion channels, leading to mitochondrial dysfunction, altered Bcl-2 family protein expression, ROS generation and disturbed calcium homeostasis. This activates ceramide-induced signaling pathways, leading to apoptosis. These events are mitigated by S1P/S1P receptors (S1PRs) that restore mitochondrial function and activate signaling pathways. SphK1 promotes survival and cell proliferation and inhibits inflammation, while SphK2 has the opposite effect. However, both SphK1 and SphK2 promote fibrosis. Thus, a ceramide-SphKs/S1P rheostat modulates oxidant-induced kidney injury by affecting mitochondrial function, ROS production, Bcl-2 family proteins, calcium homeostasis and their downstream signaling pathways. This review will summarize the current evidence for a role of interaction between ROS-antioxidants and ceramide-SphKs/S1P and of a ceramide-SphKs/S1P rheostat in the regulation of oxidative stress-mediated kidney diseases.
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Affiliation(s)
- Norishi Ueda
- Department of Pediatrics, Public Central Hospital of Matto Ishikawa, 3-8 Kuramitsu, Hakusan 924-8588, Japan
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3
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Mitoquinone supplementation alleviates oxidative stress and pathologic outcomes following repetitive mild traumatic brain injury at a chronic time point. Exp Neurol 2022; 351:113987. [DOI: 10.1016/j.expneurol.2022.113987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 11/23/2021] [Accepted: 01/13/2022] [Indexed: 11/17/2022]
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Brain Insulin Resistance: Focus on Insulin Receptor-Mitochondria Interactions. Life (Basel) 2021; 11:life11030262. [PMID: 33810179 PMCID: PMC8005009 DOI: 10.3390/life11030262] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 02/07/2023] Open
Abstract
Current hypotheses implicate insulin resistance of the brain as a pathogenic factor in the development of Alzheimer’s disease and other dementias, Parkinson’s disease, type 2 diabetes, obesity, major depression, and traumatic brain injury. A variety of genetic, developmental, and metabolic abnormalities that lead to disturbances in the insulin receptor signal transduction may underlie insulin resistance. Insulin receptor substrate proteins are generally considered to be the node in the insulin signaling system that is critically involved in the development of insulin insensitivity during metabolic stress, hyperinsulinemia, and inflammation. Emerging evidence suggests that lower activation of the insulin receptor (IR) is another common, while less discussed, mechanism of insulin resistance in the brain. This review aims to discuss causes behind the diminished activation of IR in neurons, with a focus on the functional relationship between mitochondria and IR during early insulin signaling and the related roles of oxidative stress, mitochondrial hypometabolism, and glutamate excitotoxicity in the development of IR insensitivity to insulin.
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Role of Nrf2 and mitochondria in cancer stem cells; in carcinogenesis, tumor progression, and chemoresistance. Biochimie 2020; 179:32-45. [PMID: 32946993 DOI: 10.1016/j.biochi.2020.09.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/05/2020] [Accepted: 09/04/2020] [Indexed: 02/06/2023]
Abstract
Cancer stem cells (CSCs) are rare sub-population in tumor mass with self-renewal and differentiation abilities; CSCs are considered as the main cells which are responsible for tumor metastasis, cancer recurrence, and chemo/radio-resistance. CSCs are believed to contain low mitochondria in quantity, high concentration of nuclear factor erythroid 2-related factor 2 (Nrf2), and low reactive oxygen species (ROS) levels. Mitochondria regulate certain cellular functions, including controlling of cellular energetics, calcium signaling, cell growth and cell differentiation, cell cycle regulation, and cell death. Also, mitochondria are the main sources of intrinsic ROS production. Dysfunction of CSCs mitochondria due to oxidative phosphorylation is reported in several pathological conditions, including metabolic disorders, age-related diseases, and various types of cancers. ROS levels play a significant role in cellular signal transduction and CSCs' identity and differentiation capability. Nrf2 is a master transcription factor that plays critical functions in maintaining cellular redox hemostasis by regulating several antioxidant and detoxification pathways. Recently, the critical function of Nrf2 in CSCs has been revealed by several studies. Nrf2 is an essential molecule in the maintenance of CSCs' stemness and self-renewal in response to different oxidative stresses such as chemotherapy-induced elevation of ROS. Nrf2 enables these cells to recover from chemotherapy damages, and promotes establishment of invasion and dissemination. In this study, we have summarized the role of Nrf2 and mitochondria function CSCs, which promote cancer development. The significant role of Nrf2 in the regulation of mitochondrial function and ROS levels suggests this molecule as a potential target to eradicate CSCs.
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Gao T, Shi Y, Xue Y, Yan F, Huang D, Wu Y, Weng Z. Polyphenol extract from superheated steam processed tea waste attenuates the oxidative damage in vivo and in vitro. J Food Biochem 2019; 44:e13096. [PMID: 31693210 DOI: 10.1111/jfbc.13096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/04/2019] [Accepted: 10/16/2019] [Indexed: 11/28/2022]
Abstract
In this study, tea polyphenols (TPs) was first extracted from tea waste by superheated steam (SS) pretreated ultrasonic-assisted hydrothermal extraction (UAH). The optimized strategy presented extracts with the extraction yield up to 21.19% with a significantly higher antioxidant ability, compared with the one without SS pretreatment. Further investigation proved that the SS suppressed the polyphenol oxidase activity of the TPs extract. The ability to scavenge the free radicals were compared in mouse liver mitochondria. Mitochondrial swelling, mitochondrial membrane potential (MMP), cardiolipin peroxidation, and respiratory chain complex (RCC) I-V activities were also evaluated as the index of the mitochondrial oxidative damage. The study supports evidence that the TPs extract exhibited significant protection against oxidative damage on mitochondrial. Furthermore, the effect of TPs on antioxidant ability in zebrafish embryo was evaluated. After TPs pretreatment for 1 day, zebrafish embryos showed a significantly higher survival rate as well as heart rate when facing the oxidative stress. PRACTICAL APPLICATIONS: Polyphenols from tea leaves have been viewed as an antioxidant additive in food, mainly due to the ability of scavenging free radicals and reactive oxygen species. The results of this study suggest that the SS pretreatment could be used as an efficient method to extract TPs from the tea waste for the prevention of oxidative damage in the mouse liver mitochondria and zebrafish embryos.
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Affiliation(s)
- Tingfang Gao
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Yuhong Shi
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Ying Xue
- Department of Ophthalmology, Fujian Provincial Hospital, Fuzhou, China
| | - Fen Yan
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Da Huang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Yuanzi Wu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China.,Research Institute of Photocatalysis, College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Zuquan Weng
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
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Respiration of permeabilized cardiomyocytes from mice: no sex differences, but substrate-dependent changes in the apparent ADP-affinity. Sci Rep 2019; 9:12592. [PMID: 31467353 PMCID: PMC6715638 DOI: 10.1038/s41598-019-48964-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 08/12/2019] [Indexed: 11/17/2022] Open
Abstract
Sex differences in cardiac physiology are getting increased attention. This study assessed whether isolated, permeabilized cardiomyocytes from male and female C57BL/6 mice differ in terms of their respiration with multiple substrates and overall intracellular diffusion restriction estimated by the apparent ADP-affinity of respiration. Using respirometry, we recorded 1) the activities of respiratory complexes I, II and IV, 2) the respiration rate with substrates fuelling either complex I, II, or I + II, and 3) the apparent ADP-affinity with substrates fuelling complex I and I + II. The respiration rates were normalized to protein content and citrate synthase (CS) activity. We found no sex differences in CS activity (a marker of mitochondrial content) normalized to protein content or in any of the respiration measurements. This suggests that cardiomyocytes from male and female mice do not differ in terms of mitochondrial respiratory capacity and apparent ADP-affinity. Pyruvate modestly lowered the respiration rate, when added to succinate, glutamate and malate. This may be explained by intramitochondrial compartmentalization caused by the formation of supercomplexes and their association with specific dehydrogenases. To our knowledge, we show for the first time that the apparent ADP-affinity was substrate-dependent. This suggests that substrates may change or regulate intracellular barriers in cardiomyocytes.
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Structural basis for the bi-functionality of human oxaloacetate decarboxylase FAHD1. Biochem J 2018; 475:3561-3576. [PMID: 30348641 DOI: 10.1042/bcj20180750] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/15/2018] [Accepted: 10/22/2018] [Indexed: 11/17/2022]
Abstract
Whereas enzymes in the fumarylacetoacetate hydrolase (FAH) superfamily catalyze several distinct chemical reactions, the structural basis for their multi-functionality remains elusive. As a well-studied example, human FAH domain-containing protein 1 (FAHD1) is a mitochondrial protein displaying both acylpyruvate hydrolase (ApH) and oxaloacetate decarboxylase (ODx) activity. As mitochondrial ODx, FAHD1 acts antagonistically to pyruvate carboxylase, a key metabolic enzyme. Despite its importance for mitochondrial function, very little is known about the catalytic mechanisms underlying FAHD1 enzymatic activities, and the architecture of its ligated active site is currently ill defined. We present crystallographic data of human FAHD1 that provide new insights into the structure of the catalytic center at high resolution, featuring a flexible 'lid'-like helical region which folds into a helical structure upon binding of the ODx inhibitor oxalate. The oxalate-driven structural transition results in the generation of a potential catalytic triad consisting of E33, H30 and an associated water molecule. In silico docking studies indicate that the substrate is further stabilized by a complex hydrogen-bond network, involving amino acids Q109 and K123, identified herein as potential key residues for FAHD1 catalytic activity. Mutation of amino acids H30, E33 and K123 each had discernible influence on the ApH and/or ODx activity of FAHD1, suggesting distinct catalytic mechanisms for both activities. The structural analysis presented here provides a defined structural map of the active site of FAHD1 and contributes to a better understanding of the FAH superfamily of enzymes.
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9
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Calvo-Ochoa E, Sánchez-Alegría K, Gómez-Inclán C, Ferrera P, Arias C. Palmitic acid stimulates energy metabolism and inhibits insulin/PI3K/AKT signaling in differentiated human neuroblastoma cells: The role of mTOR activation and mitochondrial ROS production. Neurochem Int 2017; 110:75-83. [DOI: 10.1016/j.neuint.2017.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/23/2017] [Accepted: 09/13/2017] [Indexed: 12/26/2022]
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10
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Han D, Johnson HS, Rao MP, Martin G, Sancheti H, Silkwood KH, Decker CW, Nguyen KT, Casian JG, Cadenas E, Kaplowitz N. Mitochondrial remodeling in the liver following chronic alcohol feeding to rats. Free Radic Biol Med 2017; 102:100-110. [PMID: 27867097 PMCID: PMC5209270 DOI: 10.1016/j.freeradbiomed.2016.11.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 09/13/2016] [Accepted: 11/10/2016] [Indexed: 02/07/2023]
Abstract
The feeding of alcohol orally (Lieber-DeCarli diet) to rats has been shown to cause declines in mitochondrial respiration (state III), decreased expression of respiratory complexes, and decreased respiratory control ratios (RCR) in liver mitochondria. These declines and other mitochondrial alterations have led to the hypothesis that alcohol feeding causes "mitochondrial dysfunction" in the liver. If oral alcohol feeding leads to mitochondrial dysfunction, one would predict that increasing alcohol delivery by intragastric (IG) alcohol feeding to rats would cause greater declines in mitochondrial bioenergetics in the liver. In this study, we examined the mitochondrial alterations that occur in rats fed alcohol both orally and intragastrically. Oral alcohol feeding decreased glutamate/malate-, acetaldehyde- and succinate-driven state III respiration, RCR, and expression of respiratory complexes (I, III, IV, V) in liver mitochondria, in agreement with previous results. IG alcohol feeding, on the other hand, caused a slight increase in glutamate/malate-driven respiration, and significantly increased acetaldehyde-driven respiration in liver mitochondria. IG feeding also caused liver mitochondria to experience a decline in succinate-driven respiration, but these decreases were smaller than those observed with oral alcohol feeding. Surprisingly, oral and IG alcohol feeding to rats increased mitochondrial respiration using other substrates, including glycerol-3-phosphate (which delivers electrons from cytoplasmic NADH to mitochondria) and octanoate (a substrate for beta-oxidation). The enhancement of glycerol-3-phosphate- and octanoate-driven respiration suggests that liver mitochondria remodeled in response to alcohol feeding. In support of this notion, we observed that IG alcohol feeding also increased expression of mitochondrial glycerol phosphate dehydrogenase-2 (GPD2), transcription factor A (TFAM), and increased mitochondrial NAD+-NADH and NADP+-NADPH levels in the liver. Our findings suggest that mitochondrial dysfunction represents an incomplete picture of mitochondrial dynamics that occur in the liver following alcohol feeding. While alcohol feeding causes some mitochondrial dysfunction (i.e. succinate-driven respiration), our work suggests that the major consequence of alcohol feeding is mitochondrial remodeling in the liver as an adaptation. This mitochondrial remodeling may play an important role in the enhanced alcohol metabolism and other adaptations in the liver that develop with alcohol intake.
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Affiliation(s)
- Derick Han
- Department of Biopharmaceutical Sciences, School of Pharmacy, Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, USA.
| | - Heather S Johnson
- University of Southern California Research Center for Liver Diseases and Southern California Research Center for ALPD, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9121, USA
| | - Madhuri P Rao
- W.M. Keck Science Department, Scripps College, Claremont, CA 91711, USA
| | - Gary Martin
- Department of Biology, Occidental College, Los Angeles, CA 90041, USA
| | - Harsh Sancheti
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
| | - Kai H Silkwood
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0303, USA
| | - Carl W Decker
- Department of Biopharmaceutical Sciences, School of Pharmacy, Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, USA
| | - Kim Tho Nguyen
- Department of Biopharmaceutical Sciences, School of Pharmacy, Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, USA
| | - Joseph G Casian
- Department of Biopharmaceutical Sciences, School of Pharmacy, Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, USA
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
| | - Neil Kaplowitz
- University of Southern California Research Center for Liver Diseases and Southern California Research Center for ALPD, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9121, USA
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Differential susceptibility of mitochondrial complex II to inhibition by oxaloacetate in brain and heart. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1561-1568. [PMID: 27287543 PMCID: PMC4990131 DOI: 10.1016/j.bbabio.2016.06.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/16/2016] [Accepted: 06/04/2016] [Indexed: 02/06/2023]
Abstract
Mitochondrial Complex II is a key mitochondrial enzyme connecting the tricarboxylic acid (TCA) cycle and the electron transport chain. Studies of complex II are clinically important since new roles for this enzyme have recently emerged in cell signalling, cancer biology, immune response and neurodegeneration. Oxaloacetate (OAA) is an intermediate of the TCA cycle and at the same time is an inhibitor of complex II with high affinity (Kd ~ 10− 8 M). Whether or not OAA inhibition of complex II is a physiologically relevant process is a significant, but still controversial topic. We found that complex II from mouse heart and brain tissue has similar affinity to OAA and that only a fraction of the enzyme in isolated mitochondrial membranes (30.2 ± 6.0% and 56.4 ± 5.6% in the heart and brain, respectively) is in the free, active form. Since OAA could bind to complex II during isolation, we established a novel approach to deplete OAA in the homogenates at the early stages of isolation. In heart, this treatment significantly increased the fraction of free enzyme, indicating that OAA binds to complex II during isolation. In brain the OAA-depleting system did not significantly change the amount of free enzyme, indicating that a large fraction of complex II is already in the OAA-bound inactive form. Furthermore, short-term ischemia resulted in a dramatic decline of OAA in tissues, but it did not change the amount of free complex II. Our data show that in brain OAA is an endogenous effector of complex II, potentially capable of modulating the activity of the enzyme. Complex II in mitochondrial membranes is inhibited by tightly-bound oxaloacetate. Oxaloacetate binds to the heart enzyme during isolation. In brain a large fraction of Complex II is present in oxaloacetate-bound form. Short-time tissue ischemia does not affect the content of the free Complex II in brain.
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12
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Chang HC, Wu R, Shang M, Sato T, Chen C, Shapiro JS, Liu T, Thakur A, Sawicki KT, Prasad SVN, Ardehali H. Reduction in mitochondrial iron alleviates cardiac damage during injury. EMBO Mol Med 2016; 8:247-67. [PMID: 26896449 PMCID: PMC4772952 DOI: 10.15252/emmm.201505748] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 01/19/2023] Open
Abstract
Excess cellular iron increases reactive oxygen species (ROS) production and causes cellular damage. Mitochondria are the major site of iron metabolism and ROS production; however, few studies have investigated the role of mitochondrial iron in the development of cardiac disorders, such as ischemic heart disease or cardiomyopathy (CM). We observe increased mitochondrial iron in mice after ischemia/reperfusion (I/R) and in human hearts with ischemic CM, and hypothesize that decreasing mitochondrial iron protects against I/R damage and the development of CM. Reducing mitochondrial iron genetically through cardiac-specific overexpression of a mitochondrial iron export protein or pharmacologically using a mitochondria-permeable iron chelator protects mice against I/R injury. Furthermore, decreasing mitochondrial iron protects the murine hearts in a model of spontaneous CM with mitochondrial iron accumulation. Reduced mitochondrial ROS that is independent of alterations in the electron transport chain's ROS producing capacity contributes to the protective effects. Overall, our findings suggest that mitochondrial iron contributes to cardiac ischemic damage, and may be a novel therapeutic target against ischemic heart disease.
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Affiliation(s)
- Hsiang-Chun Chang
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Rongxue Wu
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Meng Shang
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Tatsuya Sato
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Chunlei Chen
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jason S Shapiro
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ting Liu
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Anita Thakur
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Konrad T Sawicki
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Sathyamangla V N Prasad
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Hossein Ardehali
- Feinberg Cardiovascular Research Institute (FCVRI), Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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13
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Dinkova-Kostova AT, Abramov AY. The emerging role of Nrf2 in mitochondrial function. Free Radic Biol Med 2015; 88:179-188. [PMID: 25975984 PMCID: PMC4726722 DOI: 10.1016/j.freeradbiomed.2015.04.036] [Citation(s) in RCA: 653] [Impact Index Per Article: 72.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 12/30/2022]
Abstract
The transcription factor NF-E2 p45-related factor 2 (Nrf2; gene name NFE2L2) allows adaptation and survival under conditions of stress by regulating the gene expression of diverse networks of cytoprotective proteins, including antioxidant, anti-inflammatory, and detoxification enzymes as well as proteins that assist in the repair or removal of damaged macromolecules. Nrf2 has a crucial role in the maintenance of cellular redox homeostasis by regulating the biosynthesis, utilization, and regeneration of glutathione, thioredoxin, and NADPH and by controlling the production of reactive oxygen species by mitochondria and NADPH oxidase. Under homeostatic conditions, Nrf2 affects the mitochondrial membrane potential, fatty acid oxidation, availability of substrates (NADH and FADH2/succinate) for respiration, and ATP synthesis. Under conditions of stress or growth factor stimulation, activation of Nrf2 counteracts the increased reactive oxygen species production in mitochondria via transcriptional upregulation of uncoupling protein 3 and influences mitochondrial biogenesis by maintaining the levels of nuclear respiratory factor 1 and peroxisome proliferator-activated receptor γ coactivator 1α, as well as by promoting purine nucleotide biosynthesis. Pharmacological Nrf2 activators, such as the naturally occurring isothiocyanate sulforaphane, inhibit oxidant-mediated opening of the mitochondrial permeability transition pore and mitochondrial swelling. Curiously, a synthetic 1,4-diphenyl-1,2,3-triazole compound, originally designed as an Nrf2 activator, was found to promote mitophagy, thereby contributing to the overall mitochondrial homeostasis. Thus, Nrf2 is a prominent player in supporting the structural and functional integrity of the mitochondria, and this role is particularly crucial under conditions of stress.
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Affiliation(s)
- Albena T Dinkova-Kostova
- Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee DD1 9SY, Scotland, UK; Departments of Medicine and Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Andrey Y Abramov
- Department of Molecular Neuroscience, University College London Institute of Neurology, London WC1N 3BG, UK.
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Larsen S, Scheede-Bergdahl C, Whitesell T, Boushel R, Bergdahl A. Increased intrinsic mitochondrial respiratory capacity in skeletal muscle from rats with streptozotocin-induced hyperglycemia. Physiol Rep 2015. [PMID: 26197936 PMCID: PMC4552542 DOI: 10.14814/phy2.12467] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Type I diabetes mellitus (T1DM) is a chronic disorder, characterized by an almost or complete insulin deficiency. Widespread tissue dysfunction and deleterious diabetes-complications are associated with long-term elevations of blood glucose. The aim of this study was to investigate the effects of type I diabetes, as induced by streptozotocin, on the mitochondria in skeletal muscles that predominantly consist of either slow or fast twitch fibers. Soleus (primarily slow twitch fiber type) and the plantaris muscle (mainly fast twitch fiber type) were removed in order to measure mitochondrial protein expression and integrated mitochondrial respiratory function. Mitochondrial capacity for oxidative phosphorylation (OXPHOS) was found to be higher in the slow (more oxidative) soleus muscle from STZ rats when evaluating lipid and complex I linked OXPHOS capacity, whereas no difference was detected between the groups when evaluating the more physiological complex I and II linked OXPHOS capacity. These findings indicate that chronic hyperglycemia results in an elevated intrinsic mitochondrial respiratory capacity in both soleus and, at varying degree, plantaris muscle, findings that are consistent with human T1DM patients.
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Affiliation(s)
- Steen Larsen
- Centre for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Whitesell
- Department of Exercise Science, Concordia University, Montreal, Quebec, Canada
| | - Robert Boushel
- Department of Exercise Science, Concordia University, Montreal, Quebec, Canada The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Andreas Bergdahl
- Department of Exercise Science, Concordia University, Montreal, Quebec, Canada
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15
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Tretter L, Horvath G, Hölgyesi A, Essek F, Adam-Vizi V. Enhanced hydrogen peroxide generation accompanies the beneficial bioenergetic effects of methylene blue in isolated brain mitochondria. Free Radic Biol Med 2014; 77:317-30. [PMID: 25277417 DOI: 10.1016/j.freeradbiomed.2014.09.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 09/02/2014] [Accepted: 09/18/2014] [Indexed: 12/21/2022]
Abstract
The redox dye methylene blue (MB) is proven to have beneficial effects in various models of neurodegenerative diseases. Here we investigated the effects of MB (100 nM, 300 nM, and 1 μM) on key bioenergetic parameters and on H2O2 production/elimination in isolated guinea pig brain mitochondria under normal as well as respiration-impaired conditions. As measured by high-resolution Oxygraph the rate of resting oxygen consumption was increased, but the ADP-stimulated respiration was unaffected by MB with any of the substrates (glutamate malate, succinate, or α-glycerophosphate) used for supporting mitochondrial respiration. In mitochondria treated with inhibitors of complex I or complex III MB moderately but significantly increased the rate of ATP production, restored ΔΨm, and increased the rate of Ca(2+) uptake. The effects of MB are consistent with transferring electrons from upstream components of the electron transport chain to cytochrome c, which is energetically favorable when the flow of electrons in the respiratory chain is compromised. On the other hand, MB significantly increased the production of H2O2 measured by Amplex UltraRed fluorimetry under all conditions, in resting, ATP-synthesizing, and respiration-impaired mitochondria, with each substrate combination supporting respiration. Furthermore, it also decreased the elimination of H2O2. Generation of H2O2 without superoxide formation, observed in the presence of MB, is interpreted as a result of reduction of molecular oxygen to H2O2 by the reduced MB. The elevated generation and impaired elimination of H2O2 should be considered for the overall oxidative state of mitochondria treated with MB.
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Affiliation(s)
- L Tretter
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest H-1094, Hungary
| | - G Horvath
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest H-1094, Hungary
| | - A Hölgyesi
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest H-1094, Hungary
| | - F Essek
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest H-1094, Hungary
| | - V Adam-Vizi
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest H-1094, Hungary.
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16
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Salminen A, Kauppinen A, Hiltunen M, Kaarniranta K. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process. Ageing Res Rev 2014; 16:45-65. [PMID: 24910305 DOI: 10.1016/j.arr.2014.05.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/20/2014] [Accepted: 05/29/2014] [Indexed: 02/01/2023]
Abstract
Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
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17
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Kim C, Patel P, Gouvin LM, Brown ML, Khalil A, Henchey EM, Heuck AP, Yadava N. Comparative Analysis of the Mitochondrial Physiology of Pancreatic β Cells. ACTA ACUST UNITED AC 2014; 3:110. [PMID: 25309834 DOI: 10.4172/2167-7662.1000110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mitochondrial metabolism of β cells is thought to be highly specialized. Its direct comparison with other cells using isolated mitochondria is limited by the availability of islets/β cells in sufficient quantity. In this study, we have compared mitochondrial metabolism of INS1E/β cells with other cells in intact and permeabilized states. To selectively permeabilize the plasma membrane, we have evaluated the use of perfringolysin-O (PFO) in conjunction with microplate-based respirometry. PFO is a protein that binds membranes based on a threshold level of active cholesterol. Therefore, unless active cholesterol reaches a threshold level in mitochondria, they are expected to remain untouched by PFO. Cytochrome c sensitivity tests showed that in PFO-permeabilized cells, the mitochondrial integrity was completely preserved. Our data show that a time-dependent decline of the oligomycin-insensitive respiration observed in INS1E cells was due to a limitation in substrate supply to the respiratory chain. We predict that it is linked with the β cell-specific metabolism involving metabolites shuttling between the cytoplasm and mitochondria. In permeabilized β cells, the Complex l-dependent respiration was either transient or absent because of the inefficient TCA cycle. The TCA cycle insufficiency was confirmed by analysis of the CO2 evolution. This may be linked with lower levels of NAD+, which is required as a co-factor for CO2 producing reactions of the TCA cycle. β cells showed comparable OxPhos and respiratory capacities that were not affected by the inorganic phosphate (Pi) levels in the respiration medium. They showed lower ADP-stimulation of the respiration on different substrates. We believe that this study will significantly enhance our understanding of the β cell mitochondrial metabolism.
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Affiliation(s)
- Chul Kim
- Pioneer Valley Life Sciences Institute, Springfield, MA, USA
| | - Pinal Patel
- Pioneer Valley Life Sciences Institute, Springfield, MA, USA
| | - Lindsey M Gouvin
- Departments of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Melissa L Brown
- Pioneer Valley Life Sciences Institute, Springfield, MA, USA
| | - Ahmed Khalil
- Department of Biology, University of Massachusetts, Amherst, MA, USA
| | | | - Alejandro P Heuck
- Departments of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Nagendra Yadava
- Pioneer Valley Life Sciences Institute, Springfield, MA, USA ; Department of Biology, University of Massachusetts, Amherst, MA, USA ; Division of Endocrinology, Diabetes & Metabolism at Baystate Medical Center of Tufts University School of Medicine, Springfield, MA, USA
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18
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Persiyantseva NA, Storozhevykh TP, Senilova YE, Gorbacheva LR, Pinelis VG, Pomytkin IA. Mitochondrial H2O2 as an enable signal for triggering autophosphorylation of insulin receptor in neurons. J Mol Signal 2013; 8:11. [PMID: 24094269 PMCID: PMC3817577 DOI: 10.1186/1750-2187-8-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 10/03/2013] [Indexed: 11/22/2022] Open
Abstract
Background Insulin receptors are widely distributed in the brain, where they play roles in synaptic function, memory formation, and neuroprotection. Autophosphorylation of the receptor in response to insulin stimulation is a critical step in receptor activation. In neurons, insulin stimulation leads to a rise in mitochondrial H2O2 production, which plays a role in receptor autophosphorylation. However, the kinetic characteristics of the H2O2 signal and its functional relationships with the insulin receptor during the autophosphorylation process in neurons remain unexplored to date. Results Experiments were carried out in culture of rat cerebellar granule neurons. Kinetic study showed that the insulin-induced H2O2 signal precedes receptor autophosphorylation and represents a single spike with a peak at 5–10 s and duration of less than 30 s. Mitochondrial complexes II and, to a lesser extent, I are involved in generation of the H2O2 signal. The mechanism by which insulin triggers the H2O2 signal involves modulation of succinate dehydrogenase activity. Insulin dose–response for receptor autophosphorylation is well described by hyperbolic function (Hill coefficient, nH, of 1.1±0.1; R2=0.99). N-acetylcysteine (NAC), a scavenger of H2O2, dose-dependently inhibited receptor autophosphorylation. The observed dose response is highly sigmoidal (Hill coefficient, nH, of 8.0±2.3; R2=0.97), signifying that insulin receptor autophosphorylation is highly ultrasensitive to the H2O2 signal. These results suggest that autophosphorylation occurred as a gradual response to increasing insulin concentrations, only if the H2O2 signal exceeded a certain threshold. Both insulin-stimulated receptor autophosphorylation and H2O2 generation were inhibited by pertussis toxin, suggesting that a pertussis toxin-sensitive G protein may link the insulin receptor to the H2O2-generating system in neurons during the autophosphorylation process. Conclusions In this study, we demonstrated for the first time that the receptor autophosphorylation occurs only if mitochondrial H2O2 signal exceeds a certain threshold. This finding provides novel insights into the mechanisms underlying neuronal response to insulin. The neuronal insulin receptor is activated if two conditions are met: 1) insulin binds to the receptor, and 2) the H2O2 signal surpasses a certain threshold, thus, enabling receptor autophosphorylation in all-or-nothing manner. Although the physiological rationale for this control remains to be determined, we propose that malfunction of mitochondrial H2O2 signaling may lead to the development of cerebral insulin resistance.
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Pomytkin IA. H2O2 Signalling Pathway: A Possible Bridge between Insulin Receptor and Mitochondria. Curr Neuropharmacol 2013; 10:311-20. [PMID: 23730255 PMCID: PMC3520041 DOI: 10.2174/157015912804143559] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/07/2012] [Accepted: 06/24/2012] [Indexed: 01/20/2023] Open
Abstract
This review is focused on the mechanistic aspects of the insulin-induced H2O2 signalling pathway in neurons and the molecules affecting it, which act as risk factors for developing central insulin resistance. Insulin-induced H2O2 promotes insulin receptor activation and the mitochondria act as the insulin-sensitive H2O2 source, providing a direct molecular link between mitochondrial dysfunction and irregular insulin receptor activation. In this view, the accumulation of dysfunctional mitochondria during chronological ageing and Alzheimer's disease (AD) is a risk factor that may contribute to the development of dysfunctional cerebral insulin receptor signalling and insulin resistance. Due to the high significance of insulin-induced H2O2 for insulin receptor activation, oxidative stress-induced upregulation of antioxidant enzymes, e.g., in AD brains, may represent another risk factor contributing to the development of insulin resistance. As insulin-induced H2O2 signalling requires fully functional mitochondria, pharmacological strategies based on activating mitochondria biogenesis in the brain are central to the treatment of diseases associated with dysfunctional insulin receptor signalling in this organ.
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20
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Metabolic inflexibility and protein lysine acetylation in heart mitochondria of a chronic model of type 1 diabetes. Biochem J 2013; 449:253-61. [PMID: 23030792 DOI: 10.1042/bj20121038] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Diabetic cardiomyopathy refers to the changes in contractility that occur to the diabetic heart that can arise in the absence of vascular disease. Mitochondrial bioenergetic deficits and increased free radical production are pathological hallmarks of diabetic cardiomyopathy, but the mechanisms and causal relationships between mitochondrial deficits and the progression of disease are not understood. We evaluated cardiac mitochondrial function in a rodent model of chronic Type 1 diabetes (OVE26 mice) before the onset of contractility deficits. We found that the most pronounced change in OVE26 heart mitochondria is severe metabolic inflexibility. This inflexibility is characterized by large deficits in mitochondrial respiration measured in the presence of non-fatty acid substrates. Metabolic inflexibility occurred concomitantly with decreased activities of PDH (pyruvate dehydrogenase) and complex II. Hyper-acetylation of protein lysine was also observed. Treatment of control heart mitochondria with acetic anhydride (Ac2O), an acetylating agent, preferentially inhibited respiration by non-fatty acid substrates and increased superoxide production. We have concluded that metabolic inflexibility, induced by discrete enzymatic and molecular changes, including hyper-acetylation of protein lysine residues, precedes mitochondrial defects in a chronic rodent model of Type 1 diabetes.
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21
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Aging- and Experimental Mitochondrial Dysfunction-Related Modifications of Energy Metabolism in Brainstem Neurons. NEUROPHYSIOLOGY+ 2012. [DOI: 10.1007/s11062-012-9261-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Inhibitors of succinate: quinone reductase/Complex II regulate production of mitochondrial reactive oxygen species and protect normal cells from ischemic damage but induce specific cancer cell death. Pharm Res 2011; 28:2695-730. [PMID: 21863476 DOI: 10.1007/s11095-011-0566-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 08/10/2011] [Indexed: 12/23/2022]
Abstract
Succinate:quinone reductase (SQR) of Complex II occupies a unique central point in the mitochondrial respiratory system as a major source of electrons driving reactive oxygen species (ROS) production. It is an ideal pharmaceutical target for modulating ROS levels in normal cells to prevent oxidative stress-induced damage or alternatively,increase ROS in cancer cells, inducing cell death.The value of drugs like diazoxide to prevent ROS production,protecting normal cells, whereas vitamin E analogues promote ROS in cancer cells to kill them is highlighted. As pharmaceuticals these agents may prevent degenerative disease and their modes of action are presently being fully explored. The evidence that SDH/Complex II is tightly coupled to the NADH/NAD+ ratio in all cells,impacted by the available supplies of Krebs cycle intermediates as essential NAD-linked substrates, and the NAD+-dependent regulation of SDH/Complex II are reviewed, as are links to the NAD+-dependent dehydrogenases, Complex I and the E3 dihiydrolipoamide dehydrogenase to produce ROS. This review collates and discusses diverse sources of information relating to ROS production in different biological systems, focussing on evidence for SQR as the main source of ROS production in mitochondria, particularly its relevance to protection from oxidative stress and to the mitochondrial-targeted anti cancer drugs (mitocans) as novel cancer therapies [corrected].
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23
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Baily CN, Cason RW, Vadvalkar SS, Matsuzaki S, Humphries KM. Inhibition of mitochondrial respiration by phosphoenolpyruvate. Arch Biochem Biophys 2011; 514:68-74. [PMID: 21867675 DOI: 10.1016/j.abb.2011.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/02/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
Abstract
The cytosolic factors that influence mitochondrial oxidative phosphorylation rates are relatively unknown. In this report, we examine the effects of phosphoenolpyruvate (PEP), a glycolytic intermediate, on mitochondrial function. It is reported here that in rat heart mitochondria, PEP delays the onset of state 3 respiration in mitochondria supplied with either NADH-linked substrates or succinate. However, the maximal rate of state 3 respiration is only inhibited when oxidative phosphorylation is supported by NADH-linked substrates. The capacity of PEP to delay and/or inhibit state 3 respiration is dependent upon the presence or absence of ATP. Inhibition of state 3 is exacerbated in uncoupled mitochondria, with a 40% decrease in respiration seen with 0.1mM PEP. In contrast, ATP added exogenously or produced by oxidative phosphorylation completely prevents PEP-mediated inhibition. Mechanistically, the results support the conclusion that the main effects of PEP are to impede ADP uptake and inhibit NADH oxidation. By altering the NADH/NAD(+) status of mitochondria, it is demonstrated that PEP enhances succinate dehydrogenase activity and increase free radical production. The results of this study indicate PEP may be an important modulator of mitochondrial function under conditions of decreased ATP.
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Affiliation(s)
- C Nathan Baily
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City, USA
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Glutathione peroxidase 1 protects mitochondria against hypoxia/reoxygenation damage in mouse hearts. Pflugers Arch 2010; 460:55-68. [PMID: 20306076 DOI: 10.1007/s00424-010-0811-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 02/16/2010] [Accepted: 02/18/2010] [Indexed: 10/19/2022]
Abstract
Glutathione peroxidase 1 (GPx1) plays an important role in preventing cardiac dysfunction following ischemia-reperfusion injury. However, its role in protecting cardiac mitochondria against reoxygenation-induced reactive oxygen species (ROS) generation in vivo is unclear. We examined the role of GPx1 in protecting cardiac mitochondria against hypoxia-reoxygenation (HR) damage by testing for alterations in cardiac mitochondrial function. We used a two-dimensional gel electrophoresis proteomics analysis to examine the effects of reoxygenation on cardiac protein in wild-type (GPx1(+/+)) and GPx1 knockout (GPx1(-/-)) mouse hearts. We identified 42 protein spots showing differential expression in the two groups. Sixteen of the proteins identified were located in mitochondria and were involved in a number of key metabolic pathways. To verify our proteomics findings functionally, we performed NADH autofluorescence measurements and ATP production assays. The reduced expression of oxidative phosphorylation proteins in GPx1(-/-) mice following HR treatment resulted in loss of the mitochondrial membrane potential and decreased mitochondrial respiration. Mitochondrial ROS production and oxidative mtDNA damage were increased markedly during reoxygenation in GPx1(-/-) hearts. We also found morphological abnormalities in cardiac mitochondria and myocytes in HR-treated GPx1(-/-). This is the first report of the role of GPx1 in protecting cardiac mitochondria against reoxygenation damage in vivo. These findings will help clarify the mechanisms of HR injury and will aid in the development of antioxidant therapies to prevent cardiac mitochondrial dysfunction associated with reoxygenation.
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Zoer B, Cogolludo AL, Perez-Vizcaino F, De Mey JGR, Blanco CE, Villamor E. Hypoxia sensing in the fetal chicken femoral artery is mediated by the mitochondrial electron transport chain. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1026-34. [PMID: 20089711 DOI: 10.1152/ajpregu.00500.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular hypoxia sensing is transduced into vasoconstriction in the pulmonary circulation, whereas systemic arteries dilate. Mitochondrial electron transport chain (mETC), reactive O(2) species (ROS), and K(+) channels have been implicated in the sensing/signaling mechanisms of hypoxic relaxation in mammalian systemic arteries. We aimed to investigate their putative roles in hypoxia-induced relaxation in fetal chicken (19 days of incubation) femoral arteries mounted in a wire myograph. Acute hypoxia (Po(2) approximately 2.5 kPa) relaxed the contraction induced by norepinephrine (1 microM). Hypoxia-induced relaxation was abolished or significantly reduced by the mETC inhibitors rotenone (complex I), myxothiazol and antimycin A (complex III), and NaN(3) (complex IV). The complex II inhibitor 3-nitroproprionic acid enhanced the hypoxic relaxation. In contrast, the relaxations mediated by acetylcholine, sodium nitroprusside, or forskolin were not affected by the mETC blockers. Hypoxia induced a slight increase in ROS production (as measured by 2,7-dichlorofluorescein-fluorescence), but hypoxia-induced relaxation was not affected by scavenging of superoxide (polyethylene glycol-superoxide dismutase) or H(2)O(2) (polyethylene glycol-catalase) or by NADPH-oxidase inhibition (apocynin). Also, the K(+) channel inhibitors tetraethylammonium (nonselective), diphenyl phosphine oxide-1 (voltage-gated K(+) channel 1.5), glibenclamide (ATP-sensitive K(+) channel), iberiotoxin (large-conductance Ca(2+)-activated K(+) channel), and BaCl(2) (inward-rectifying K(+) channel), as well as ouabain (Na(+)-K(+)-ATPase inhibitor) did not affect hypoxia-induced relaxation. The relaxation was enhanced in the presence of the voltage-gated K(+) channel blocker 4-aminopyridine. In conclusion, our experiments suggest that the mETC plays a critical role in O(2) sensing in fetal chicken femoral arteries. In contrast, hypoxia-induced relaxation appears not to be mediated by ROS or K(+) channels.
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Affiliation(s)
- Bea Zoer
- University Hospital Maastricht, P. Debyelaan 25, AZ Maastricht, The Netherlands
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