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Yamamoto K, Shimogonya Y, Maeno R, Kawabe K, Ando J. Endothelial cells differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes. Am J Physiol Cell Physiol 2023; 325:C1532-C1544. [PMID: 37927239 PMCID: PMC10861177 DOI: 10.1152/ajpcell.00393.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/19/2023] [Accepted: 10/28/2023] [Indexed: 11/07/2023]
Abstract
Endothelial cells (ECs) experience two different blood flow patterns: laminar and disturbed flow. Their responses to laminar flow contribute to vascular homeostasis, whereas their responses to disturbed flow result in EC dysfunction and vascular diseases. However, it remains unclear how ECs differentially sense laminar and disturbed flow and trigger signaling that elicits different responses. Here, we showed that ECs differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes in opposite directions. This results in distinct changes in mitochondrial function, namely, increased adenosine triphosphate (ATP) production for laminar flow and increased hydrogen peroxide (H2O2) release for disturbed flow, leading to ATP- and H2O2-mediated signaling, respectively. When cultured human aortic ECs were subjected to laminar or disturbed flow in flow-loading devices, the lipid order of their plasma membranes immediately decreased in response to laminar flow and increased in response to disturbed flow. Laminar flow also decreased the lipid order of mitochondrial membranes and increased mitochondrial ATP production. In contrast, disturbed flow increased the lipid order of mitochondrial membranes and increased the release of H2O2 from the mitochondria. The addition of cholesterol to the cells increased the lipid order of both membranes and abrogated laminar flow-induced ATP production, while treatment of the cells with a cholesterol-depleting reagent, methyl-β cyclodextrin, decreased the lipid order of both membranes and abolished disturbed flow-induced H2O2 release, indicating that changes in the membrane lipid order and/or cholesterol content are closely linked to flow-induced changes in mitochondrial functions.NEW & NOTEWORTHY How vascular endothelial cells (ECs) differentially sense laminar and disturbed flows and trigger intracellular signaling remains unclear. Here, we show that EC plasma membranes act as mechanosensors to discriminate between laminar and disturbed flows by undergoing opposite changes in their lipid order. Similar lipid order changes occur simultaneously in the mitochondrial membranes, which are linked to changes in mitochondrial function, that is, increased ATP production for laminar flow and increased H2O2 release for disturbed flow.
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Affiliation(s)
- Kimiko Yamamoto
- Laboratory of System Physiology, Department of Biomedical Engineering, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuji Shimogonya
- Department of Mechanical Engineering, College of Engineering, Nihon University, Koriyama, Japan
| | - Ryohei Maeno
- Laboratory of System Physiology, Department of Biomedical Engineering, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Division of Vascular Surgery, Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenshiroh Kawabe
- Laboratory of System Physiology, Department of Biomedical Engineering, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Division of Vascular Surgery, Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Joji Ando
- Laboratory of Biomedical Engineering, School of Medicine, Dokkyo Medical University, Tochigi, Japan
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2
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Grayson C, Mailloux RJ. Coenzyme Q 10 and nicotinamide nucleotide transhydrogenase: Sentinels for mitochondrial hydrogen peroxide signaling. Free Radic Biol Med 2023; 208:260-271. [PMID: 37573896 DOI: 10.1016/j.freeradbiomed.2023.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/21/2023] [Accepted: 08/08/2023] [Indexed: 08/15/2023]
Abstract
Mitochondria use hydrogen peroxide (H2O2) as a mitokine for cell communication. H2O2 output for signaling depends on its rate of production and degradation, both of which are strongly affected by the redox state of the coenzyme Q10 (CoQ) pool and NADPH availability. Here, we propose the CoQ pool and nicotinamide nucleotide transhydrogenase (NNT) have evolved to be central modalities for mitochondrial H2O2 signaling. Both factors play opposing yet equally important roles in dictating H2O2 availability because they are connected to one another by two central parameters in bioenergetics: electron supply and Δp. The CoQ pool is the central point of convergence for electrons from various dehydrogenases and the electron transport chain (ETC). The increase in Δp creates a significant amount of protonic backpressure on mitochondria to promote H2O2 genesis through CoQ pool reduction. These same factors also drive the activity of NNT, which uses electrons and the Δp to eliminate H2O2. In this way, electron supply and the magnitude of the Δp manifests as a redox connection between the two sentinels, CoQ and NNT, which serve as opposing yet equally important forces required for budgeting H2O2. Taken together, CoQ and NNT are sentinels linked through mitochondrial bioenergetics to manage H2O2 availability for interorganelle and intercellular redox signaling.
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Affiliation(s)
- Cathryn Grayson
- The School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Ste.-Anne-de-Bellevue, Quebec, Canada
| | - Ryan J Mailloux
- The School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Ste.-Anne-de-Bellevue, Quebec, Canada.
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3
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Wang Y, Wu J, Wang J, He L, Lai H, Zhang T, Wang X, Li W. Mitochondrial oxidative stress in brain microvascular endothelial cells: Triggering blood-brain barrier disruption. Mitochondrion 2023; 69:71-82. [PMID: 36709855 DOI: 10.1016/j.mito.2023.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/02/2023] [Accepted: 01/22/2023] [Indexed: 01/27/2023]
Abstract
Blood-brain barrier disruption plays an important role in central nervous system diseases. This review provides information on the role of mitochondrial oxidative stress in brain microvascular endothelial cells in cellular dysfunction, the disruption of intercellular junctions, transporter dysfunction, abnormal angiogenesis, neurovascular decoupling, and the involvement and aggravation of vascular inflammation and illustrates related molecular mechanisms. In addition, recent drug and nondrug therapies targeting cerebral vascular endothelial cell mitochondria to repair the blood-brain barrier are discussed. This review shows that mitochondrial oxidative stress disorder in brain microvascular endothelial cells plays a key role in the occurrence and development of blood-brain barrier damage and may be critical in various pathological mechanisms of blood-brain barrier damage. These new findings suggest a potential new strategy for the treatment of central nervous system diseases through mitochondrial modulation of cerebral vascular endothelial cells.
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Affiliation(s)
- Yi Wang
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Jing Wu
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Jiexin Wang
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Linxi He
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Han Lai
- School of Foreign Languages, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Tian Zhang
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Xin Wang
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
| | - Weihong Li
- Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province 610000, PR China.
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4
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Grb2 interacts with necrosome components and is involved in rasfonin-induced necroptosis. Cell Death Dis 2022; 8:319. [PMID: 35831301 PMCID: PMC9279413 DOI: 10.1038/s41420-022-01106-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 11/22/2022]
Abstract
The underlying mechanism by which growth factor receptor-bound protein 2 (Grb2) regulates necroptosis remains unexplored. In the present study, we found that rasfonin, a fungal natural product and an activator of necroptosis, enhanced Grb2 binding to receptor-interacting serine/threonine kinase 1 (RIP1), which plays a critical role in regulating programmed necrosis. Moreover, we observed that SQSTM/p62 (p62), a protein that can form necrosomes with RIP1, increased its interaction with Grb2 upon rasfonin challenge. Although it has been used as an activator of autophagy in our previous study, here we found that a high dose of rasfonin was able to inhibit autophagic process. Inhibition of RIP1 either chemically or genetically reversed the inhibition of rasfonin on autophagy, whereas knockdown of Grb2 markedly reduced rasfonin-induced necrosis. Additionally, we found that the compound failed to upregulate the expression of RIP1 in Grb2-deprived cells. In summary, our data revealed that Grb2 actively participated in rasfonin-induced necroptosis by interacting with the components of necrosome and mediating their expression.
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5
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Valle MS, Russo C, Malaguarnera L. Protective role of vitamin D against oxidative stress in diabetic retinopathy. Diabetes Metab Res Rev 2021; 37:e3447. [PMID: 33760363 DOI: 10.1002/dmrr.3447] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 02/01/2021] [Accepted: 02/15/2021] [Indexed: 02/06/2023]
Abstract
Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus. There is much evidence showing that a high level of mitochondrial overproduction of reactive oxygen species in the diabetic retina contributes in modifying cellular signalling and leads to retinal cell damage and finally to the development of DR pathogenesis. In the last few decades, it has been reported that vitamin D is involved in DR pathogenesis. Vitamin D, traditionally known as an essential nutrient crucial in bone metabolism, has also been proven to be a very effective antioxidant. It has been demonstrated that it modulates the production of advanced glycosylated end products, as well as several pathways including protein kinase C, the polyol pathway leading to the reduction of free radical formation. It prevents the translocation of nuclear factor kappa B, preventing the inflammatory response, acting as an immunomodulator, and modulates autophagy and apoptosis. In this review, we explore the molecular mechanisms by which vitamin D protects the eye from oxidative stress, in order to evaluate whether vitamin D supplementation may be useful to mitigate the deleterious effects of free radicals in DR.
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Affiliation(s)
- Maria Stella Valle
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Cristina Russo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Lucia Malaguarnera
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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6
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Fu P, Epshtein Y, Ramchandran R, Mascarenhas JB, Cress AE, Jacobson J, Garcia JGN, Natarajan V. Essential role for paxillin tyrosine phosphorylation in LPS-induced mitochondrial fission, ROS generation and lung endothelial barrier loss. Sci Rep 2021; 11:17546. [PMID: 34475475 PMCID: PMC8413352 DOI: 10.1038/s41598-021-97006-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 08/12/2021] [Indexed: 11/09/2022] Open
Abstract
We have shown that both reactive oxygen species (ROS) and paxillin tyrosine phosphorylation regulate LPS-induced human lung endothelial permeability. Mitochondrial ROS (mtROS) is known to increase endothelial cell (EC) permeability which requires dynamic change in mitochondrial morphology, events that are likely to be regulated by paxillin. Here, we investigated the role of paxillin and its tyrosine phosphorylation in regulating LPS-induced mitochondrial dynamics, mtROS production and human lung microvascular EC (HLMVEC) dysfunction. LPS, in a time-dependent manner, induced higher levels of ROS generation in the mitochondria compared to cytoplasm or nucleus. Down-regulation of paxillin expression with siRNA or ecto-expression of paxillin Y31F or Y118F mutant plasmids attenuated LPS-induced mtROS in HLMVECs. Pre-treatment with MitoTEMPO, a scavenger of mtROS, attenuated LPS-induced mtROS, endothelial permeability and VE-cadherin phosphorylation. Further, LPS-induced mitochondrial fission in HLMVECs was attenuated by both a paxillin siRNA, and paxillin Y31F/Y118F mutant. LPS stimulated phosphorylation of dynamin-related protein (DRP1) at S616, which was also attenuated by paxillin siRNA, and paxillinY31/Y118 mutants. Inhibition of DRP1 phosphorylation by P110 attenuated LPS-induced mtROS and endothelial permeability. LPS challenge of HLMVECs enhanced interaction between paxillin, ERK, and DRP1, and inhibition of ERK1/2 activation with PD98059 blocked mitochondrial fission. Taken together, these results suggest a key role for paxillin tyrosine phosphorylation in LPS-induced mitochondrial fission, mtROS generation and EC barrier dysfunction.
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Affiliation(s)
- Panfeng Fu
- Department of Pharmacology, University of Illinois at Chicago, COMRB Room # 3137, 909, South Wolcott Avenue, Chicago, IL, 60612, USA. .,The Affiliated Hospital of Medical School, Medical School of Ningbo University, 247 Renmin Road, Ningbo, China.
| | - Yulia Epshtein
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ramaswamy Ramchandran
- Department of Pharmacology, University of Illinois at Chicago, COMRB Room # 3137, 909, South Wolcott Avenue, Chicago, IL, 60612, USA
| | - Joseph B Mascarenhas
- Department of Medicine, College of Medicine, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Anne E Cress
- Departments of Cellular and Molecular Medicine, University of Arizona Health Sciences, Tucson, AZ, USA.,Department of Medicine, College of Medicine, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Jeffrey Jacobson
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Joe G N Garcia
- Department of Medicine, College of Medicine, University of Arizona Health Sciences, Tucson, AZ, USA
| | - Viswanathan Natarajan
- Department of Pharmacology, University of Illinois at Chicago, COMRB Room # 3137, 909, South Wolcott Avenue, Chicago, IL, 60612, USA. .,Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
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7
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Zheleznova NN, Kumar V, Kurth T, Cowley AW. Hydrogen peroxide (H 2O 2) mediated activation of mTORC2 increases intracellular Na + concentration in the renal medullary thick ascending limb of Henle. Sci Rep 2021; 11:7300. [PMID: 33790341 PMCID: PMC8012714 DOI: 10.1038/s41598-021-86678-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 03/05/2021] [Indexed: 11/22/2022] Open
Abstract
Hydrogen peroxide (H2O2) production in the renal outer medulla is an important determinant of renal medullary blood flow and blood pressure (BP) salt-sensitivity in Dahl salt-sensitive (SS) rats. The mechanisms and pathways responsible for these actions are poorly understood. Recently, we have discovered that the mTOR complex 2 (mTORC2) plays a critical role in BP salt-sensitivity of SS rats by regulating Na+ homeostasis. PP242, an inhibitor of mTORC1/2 pathways exhibits potent natriuretic actions and completely prevented salt-induced hypertension in SS rats. In the present study, we have found that chronic infusion of H2O2 into the single remaining kidney of Sprague Dawley (SD) rats (3 days) stimulated the functional marker (pAKTSer473/AKT) of mTORC2 activity measured by Western Blot analysis. No changes in mTORC1 activity in OM were observed as determined by pS6Ser235/236/S6. Using fluorescent microscopy and the Na+ sensitive dye Sodium Green, we have shown that H2O2 (100 µM added in the bath) increased intracellular sodium concentration ([Na+]i) in renal medullary thick ascending limbs (mTALs) isolated from SD rats. These responses were almost completely abolished by pretreatment of mTAL with 10 µM PP242, indicating that mTORC1/2 pathways were involved in the H2O2 induced increase of [Na+]i. mTAL cell volume remained unchanged (± 1%) by H2O2 as determined by 3D reconstruction confocal laser scanning microscopy techniques. Consistent with the microscopy data, Western Blot analysis of proteins obtained from freshly isolated mTAL treated with 100 µM H2O2 exhibited increased activity/phosphorylation of AKT (pAKTSer473/AKT) that was inhibited by PP242. This was associated with increased protein activity of the apical membrane cotransporter Na+-K+-2Cl- (NKCC2) and the Na/H exchanger (NHE-3). Na+-K+-ATPase activity was increased as reflected an increase in the ratio of pNa+-K+-ATPaseSer16 to total Na+-K+-ATPase. Overall, the results indicate that H2O2 mediated activation of mTORC2 plays a key role in transducing the observed increases of cytosolic [Na+]i despite associated increases of basolateral pump activity.
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Affiliation(s)
- Nadezhda N Zheleznova
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
| | - Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
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8
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Cross-Talk between NADPH Oxidase and Mitochondria: Role in ROS Signaling and Angiogenesis. Cells 2020; 9:cells9081849. [PMID: 32781794 PMCID: PMC7466096 DOI: 10.3390/cells9081849] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/27/2020] [Accepted: 08/05/2020] [Indexed: 02/07/2023] Open
Abstract
Angiogenesis, a new vessel formation from the pre-existing ones, is essential for embryonic development, wound repair and treatment of ischemic heart and limb diseases. However, dysregulated angiogenesis contributes to various pathologies such as diabetic retinopathy, atherosclerosis and cancer. Reactive oxygen species (ROS) derived from NADPH oxidase (NOX) as well as mitochondria play an important role in promoting the angiogenic switch from quiescent endothelial cells (ECs). However, how highly diffusible ROS produced from different sources and location can communicate with each other to regulate angiogenesis remains unclear. To detect a localized ROS signal in distinct subcellular compartments in real time in situ, compartment-specific genetically encoded redox-sensitive fluorescence biosensors have been developed. Recently, the intercellular communication, “cross-talk”, between ROS derived from NOX and mitochondria, termed “ROS-induced ROS release”, has been proposed as a mechanism for ROS amplification at distinct subcellular compartments, which are essential for activation of redox signaling. This “ROS-induced ROS release” may represent a feed-forward mechanism of localized ROS production to maintain sustained signaling, which can be targeted under pathological conditions with oxidative stress or enhanced to promote therapeutic angiogenesis. In this review, we summarize the recent knowledge regarding the role of the cross-talk between NOX and mitochondria organizing the sustained ROS signaling involved in VEGF signaling, neovascularization and tissue repair.
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9
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Shen Y, Ye B, Chen P, Wang Q, Fan C, Shu Y, Xiang M. Cognitive Decline, Dementia, Alzheimer's Disease and Presbycusis: Examination of the Possible Molecular Mechanism. Front Neurosci 2018; 12:394. [PMID: 29937713 PMCID: PMC6002513 DOI: 10.3389/fnins.2018.00394] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
The incidences of presbycusis and dementia are high among geriatric diseases. Presbycusis is the general term applied to age-related hearing loss and can be caused by many risk factors, such as noise exposure, smoking, medication, hypertension, family history, and other factors. Mutation of mitochondrial DNA in hair cells, spiral ganglion cells, and stria vascularis cells of the cochlea is the basic mechanism of presbycusis. Dementia is a clinical syndrome that includes the decline of cognitive and conscious states and is caused by many neurodegenerative diseases, of which Alzheimer’s disease (AD) is the most common. The amyloid cascade hypothesis and tau hypothesis are the two major hypotheses that describe the AD pathogenic mechanism. Recent studies have shown that deposition of Aβ and hyperphosphorylation of the tau protein may cause mitochondrial dysfunction. An increasing number of papers have reported that, on one hand, the auditory system function in AD patients is damaged as their cognitive ability declines and that, on the other hand, hearing loss may be a risk factor for dementia and AD. However, the relationship between presbycusis and AD is still unknown. By reviewing the relevant literature, we found that the SIRT1-PGC1α pathway and LKB1 (or CaMKKβ)-AMPK pathway may play a role in the preservation of cerebral neuron function by taking part in the regulation of mitochondrial function. Then vascular endothelial growth factor signal pathway is activated to promote vascular angiogenesis and maintenance of the blood–brain barrier integrity. Recently, experiments have also shown that their expression levels are altered in both presbycusis and AD mouse models. Therefore, we propose that exploring the specific molecular link between presbycusis and AD may provide new ideas for their prevention and treatment.
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Affiliation(s)
- Yilin Shen
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Bin Ye
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Penghui Chen
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Department of Otolaryngology & Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Quan Wang
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Cui Fan
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yilai Shu
- Department of Otolaryngology & Head and Neck Surgery, EENT Hospital, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine, National Health and Family Planning Commission, Shanghai, China
| | - Mingliang Xiang
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
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10
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Suresh K, Shimoda LA. Endothelial Cell Reactive Oxygen Species and Ca 2+ Signaling in Pulmonary Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 967:299-314. [PMID: 29047094 DOI: 10.1007/978-3-319-63245-2_18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pulmonary hypertension (PH) refers to a disorder characterized by elevated pulmonary arterial pressure, leading to right ventricular overload and eventually right ventricular failure, which results in high morbidity and mortality. PH is associated with heterogeneous etiologies and distinct molecular mechanisms, including abnormal migration and proliferation of endothelial and smooth muscle cells. Although the exact details are not fully elucidated, reactive oxygen species (ROS) have been shown to play a key role in promoting abnormal function in pulmonary arterial smooth muscle and endothelial cells in PH. In endothelial cells, ROS can be generated from sources such as NADPH oxidase and mitochondria, which in turn can serve as signaling molecules in a wide variety of processes including posttranslational modification of proteins involved in Ca2+ homeostasis. In this chapter, we discuss the role of ROS in promoting abnormal vasoreactivity and endothelial migration and proliferation in various models of PH. Furthermore, we draw particular attention to the role of ROS-induced increases in intracellular Ca2+ concentration in the pathobiology of PH.
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Affiliation(s)
- Karthik Suresh
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA. .,Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA.
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21224, USA
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11
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Kim YM, Kim SJ, Tatsunami R, Yamamura H, Fukai T, Ushio-Fukai M. ROS-induced ROS release orchestrated by Nox4, Nox2, and mitochondria in VEGF signaling and angiogenesis. Am J Physiol Cell Physiol 2017; 312:C749-C764. [PMID: 28424170 DOI: 10.1152/ajpcell.00346.2016] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 04/10/2017] [Accepted: 04/10/2017] [Indexed: 01/07/2023]
Abstract
Reactive oxygen species (ROS) derived from NADPH oxidase (NOX) and mitochondria play a critical role in growth factor-induced switch from a quiescent to an angiogenic phenotype in endothelial cells (ECs). However, how highly diffusible ROS produced from different sources can coordinate to stimulate VEGF signaling and drive the angiogenic process remains unknown. Using the cytosol- and mitochondria-targeted redox-sensitive RoGFP biosensors with real-time imaging, here we show that VEGF stimulation in human ECs rapidly increases cytosolic RoGFP oxidation within 1 min, followed by mitochondrial RoGFP oxidation within 5 min, which continues at least for 60 min. Silencing of Nox4 or Nox2 or overexpression of mitochondria-targeted catalase significantly inhibits VEGF-induced tyrosine phosphorylation of VEGF receptor type 2 (VEGFR2-pY), EC migration and proliferation at the similar extent. Exogenous hydrogen peroxide (H2O2) or overexpression of Nox4, which produces H2O2, increases mitochondrial ROS (mtROS), which is prevented by Nox2 siRNA, suggesting that Nox2 senses Nox4-derived H2O2 to promote mtROS production. Mechanistically, H2O2 increases S36 phosphorylation of p66Shc, a key mtROS regulator, which is inhibited by siNox2, but not by siNox4. Moreover, Nox2 or Nox4 knockdown or overexpression of S36 phosphorylation-defective mutant p66Shc(S36A) inhibits VEGF-induced mtROS, VEGFR2-pY, EC migration, and proliferation. In summary, Nox4-derived H2O2 in part activates Nox2 to increase mtROS via pSer36-p66Shc, thereby enhancing VEGFR2 signaling and angiogenesis in ECs. This may represent a novel feed-forward mechanism of ROS-induced ROS release orchestrated by the Nox4/Nox2/pSer36-p66Shc/mtROS axis, which drives sustained activation of angiogenesis signaling program.
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Affiliation(s)
- Young-Mee Kim
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Departments of Medicine (Cardiology) and Pharmacology, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois
| | - Seok-Jo Kim
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Pharmacology, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois
| | - Ryosuke Tatsunami
- School of Pharmacy, Hokkaido Pharmaceutical University, Hokkaido, Japan; and.,Department of Pharmacology, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Tohru Fukai
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia.,Departments of Medicine (Cardiology) and Pharmacology, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois
| | - Masuko Ushio-Fukai
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, Georgia; .,Department of Pharmacology, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois
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12
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Diaz M, Degens H, Vanhees L, Austin C, Azzawi M. The effects of resveratrol on aging vessels. Exp Gerontol 2016; 85:41-47. [PMID: 27666185 DOI: 10.1016/j.exger.2016.09.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 09/14/2016] [Accepted: 09/19/2016] [Indexed: 12/22/2022]
Abstract
Aging is a major risk factor for the development of cardiovascular disease. Despite a significant reduction in the mortality and morbidity rates over the last decade, the socio-economic burden of cardiovascular disease is still substantial. Consequently, there is a considerable need for alternative strategies, such as nutraceutical supplementation, that delay the functional vascular decline present in the elderly. Compromised autophagy and oxidative stress (OS) are considered major causes of the age-related endothelial dysfunction. OS reduces the bioavailability of nitric oxide (NO), which has been associated with hypertension, arteriosclerosis, and a reduced vasodilatory response. High levels of free radicals and the low bioavailability of NO lead to a positive feedback loop of further OS, organelle damage, poor repair, and endothelial dysfunction. Here we draw attention to the relationship between OS and autophagy in the aged vasculature. We have reviewed the published literature and provided arguments that support that treatment with resveratrol stimulates autophagy and thereby has the potential to restore oxidative balance in the endothelium, which indicates that treatment with resveratrol might have therapeutic potential to restore endothelial function in the elderly.
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Affiliation(s)
- Miguel Diaz
- School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK; Department of Rehabilitation Sciences, University of Leuven, Belgium
| | - Hans Degens
- School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK; Sports Science and Innovation Institute, Lithuanian Sports University, Kaunas, Lithuania
| | - Luc Vanhees
- Department of Rehabilitation Sciences, University of Leuven, Belgium
| | - Clare Austin
- Faculty of Health and Social Care, Edge Hill University, Lancashire, UK
| | - May Azzawi
- School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.
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13
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Forrester SJ, Kawai T, O'Brien S, Thomas W, Harris RC, Eguchi S. Epidermal Growth Factor Receptor Transactivation: Mechanisms, Pathophysiology, and Potential Therapies in the Cardiovascular System. Annu Rev Pharmacol Toxicol 2015; 56:627-53. [PMID: 26566153 DOI: 10.1146/annurev-pharmtox-070115-095427] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epidermal growth factor receptor (EGFR) activation impacts the physiology and pathophysiology of the cardiovascular system, and inhibition of EGFR activity is emerging as a potential therapeutic strategy to treat diseases including hypertension, cardiac hypertrophy, renal fibrosis, and abdominal aortic aneurysm. The capacity of G protein-coupled receptor (GPCR) agonists, such as angiotensin II (AngII), to promote EGFR signaling is called transactivation and is well described, yet delineating the molecular processes and functional relevance of this crosstalk has been challenging. Moreover, these critical findings are dispersed among many different fields. The aim of our review is to highlight recent advancements in defining the signaling cascades and downstream consequences of EGFR transactivation in the cardiovascular renal system. We also focus on studies that link EGFR transactivation to animal models of the disease, and we discuss potential therapeutic applications.
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Affiliation(s)
- Steven J Forrester
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140;
| | - Tatsuo Kawai
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140;
| | - Shannon O'Brien
- The School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Walter Thomas
- The School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Raymond C Harris
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Satoru Eguchi
- Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140;
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A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling. Proc Natl Acad Sci U S A 2015; 112:E5679-88. [PMID: 26438848 DOI: 10.1073/pnas.1517932112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) govern cellular homeostasis by inducing signaling. H2O2 modulates the activity of phosphatases and many other signaling molecules through oxidation of critical cysteine residues, which led to the notion that initiation of ROS signaling is broad and nonspecific, and thus fundamentally distinct from other signaling pathways. Here, we report that H2O2 signaling bears hallmarks of a regular signal transduction cascade. It is controlled by hierarchical signaling events resulting in a focused response as the results place the mitochondrial respiratory chain upstream of tyrosine-protein kinase Lyn, Lyn upstream of tyrosine-protein kinase SYK (Syk), and Syk upstream of numerous targets involved in signaling, transcription, translation, metabolism, and cell cycle regulation. The active mediators of H2O2 signaling colocalize as H2O2 induces mitochondria-associated Lyn and Syk phosphorylation, and a pool of Lyn and Syk reside in the mitochondrial intermembrane space. Finally, the same intermediaries control the signaling response in tissues and species responsive to H2O2 as the respiratory chain, Lyn, and Syk were similarly required for H2O2 signaling in mouse B cells, fibroblasts, and chicken DT40 B cells. Consistent with a broad role, the Syk pathway is coexpressed across tissues, is of early metazoan origin, and displays evidence of evolutionary constraint in the human. These results suggest that H2O2 signaling is under control of a signal transduction pathway that links the respiratory chain to the mitochondrial intermembrane space-localized, ubiquitous, and ancient Syk pathway in hematopoietic and nonhematopoietic cells.
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15
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Biological Activities of Reactive Oxygen and Nitrogen Species: Oxidative Stress versus Signal Transduction. Biomolecules 2015; 5:472-84. [PMID: 25884116 PMCID: PMC4496681 DOI: 10.3390/biom5020472] [Citation(s) in RCA: 377] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/30/2015] [Accepted: 04/02/2015] [Indexed: 12/12/2022] Open
Abstract
In the past, reactive oxygen and nitrogen species (RONS) were shown to cause oxidative damage to biomolecules, contributing to the development of a variety of diseases. However, recent evidence has suggested that intracellular RONS are an important component of intracellular signaling cascades. The aim of this review was to consolidate old and new ideas on the chemical, physiological and pathological role of RONS for a better understanding of their properties and specific activities. Critical consideration of the literature reveals that deleterious effects do not appear if only one primary species (superoxide radical, nitric oxide) is present in a biological system, even at high concentrations. The prerequisite of deleterious effects is the formation of highly reactive secondary species (hydroxyl radical, peroxynitrite), emerging exclusively upon reaction with another primary species or a transition metal. The secondary species are toxic, not well controlled, causing irreversible damage to all classes of biomolecules. In contrast, primary RONS are well controlled (superoxide dismutase, catalase), and their reactions with biomolecules are reversible, making them ideal for physiological/pathophysiological intracellular signaling. We assume that whether RONS have a signal transducing or damaging effect is primarily defined by their quality, being primary or secondary RONS, and only secondly by their quantity.
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16
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Gul MZ, Kalam S, Singh R, Ankati S. Free Radicals: Implications in Etiology of Chronic Diseases and Their Amelioration through Nutraceuticals. ACTA ACUST UNITED AC 2015. [DOI: 10.5567/pharmacologia.2015.11.20] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Squamosamide derivative FLZ protects retinal pigment epithelium cells from oxidative stress through activation of epidermal growth factor receptor (EGFR)-AKT signaling. Int J Mol Sci 2014; 15:18762-75. [PMID: 25329617 PMCID: PMC4227245 DOI: 10.3390/ijms151018762] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/02/2014] [Accepted: 09/11/2014] [Indexed: 12/19/2022] Open
Abstract
Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is attributed to age-related macular degeneration (AMD) pathogenesis. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, Annona glabra, has displayed significant cyto-protective activity. In the current study, we explored the pro-survival effect of FLZ in oxidative stressed-RPE cells and studied the underlying signaling mechanisms. Our results showed that FLZ attenuated hydrogen peroxide (H2O2)-induced viability decrease and apoptosis in the RPE cell line (ARPE-19 cells) and in primary mouse RPE cells. Western blotting results showed that FLZ activated AKT signaling in RPE cells. The AKT-specific inhibitor, MK-2206, the phosphoinositide 3-kinase (PI3K)/AKT pan inhibitor, wortmannin, and AKT1-shRNA (short hairpin RNA) depletion almost abolished FLZ-mediated pro-survival/anti-apoptosis activity. We discovered that epidermal growth factor receptor (EGFR) trans-activation mediated FLZ-induced AKT activation and the pro-survival effect in RPE cells, and the anti-apoptosis effect of FLZ against H2O2 was inhibited by the EGFR inhibitor, PD153035, or by EGFR shRNA-knockdown. In conclusion, FLZ protects RPE cells from oxidative stress through activation of EGFR-AKT signaling, and our results suggest that FLZ might have therapeutic values for AMD.
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18
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Bretón-Romero R, Lamas S. Hydrogen peroxide signaling in vascular endothelial cells. Redox Biol 2014; 2:529-34. [PMID: 24634835 PMCID: PMC3953958 DOI: 10.1016/j.redox.2014.02.005] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/20/2014] [Indexed: 12/27/2022] Open
Abstract
Redox signaling is implicated in different physiological and pathological events in the vasculature. Among the different reactive oxygen species, hydrogen peroxide (H2O2) is a very good candidate to perform functions as an intracellular messenger in the regulation of several biological events. In this review, we summarize the main physiological sources of H2O2 in the endothelium and the molecular mechanisms by which it is able to act as a signaling mediator in the vasculature.
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Affiliation(s)
- Rosa Bretón-Romero
- Centro de Biología Molecular 'Severo Ochoa' CSIC-UAM, Campus Universidad Autónoma, Nicolás Cabrera 1, Madrid E-28049, Spain
| | - Santiago Lamas
- Centro de Biología Molecular 'Severo Ochoa' CSIC-UAM, Campus Universidad Autónoma, Nicolás Cabrera 1, Madrid E-28049, Spain
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19
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Reactive oxygen species are required for 5-HT-induced transactivation of neuronal platelet-derived growth factor and TrkB receptors, but not for ERK1/2 activation. PLoS One 2013; 8:e77027. [PMID: 24086766 PMCID: PMC3785432 DOI: 10.1371/journal.pone.0077027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 09/05/2013] [Indexed: 02/05/2023] Open
Abstract
High concentrations of reactive oxygen species (ROS) induce cellular damage, however at lower concentrations ROS act as intracellular second messengers. In this study, we demonstrate that serotonin (5-HT) transactivates the platelet-derived growth factor (PDGF) type β receptor as well as the TrkB receptor in neuronal cultures and SH-SY5Y cells, and that the transactivation of both receptors is ROS-dependent. Exogenous application of H2O2 induced the phosphorylation of these receptors in a dose-dependent fashion, similar to that observed with 5-HT. However the same concentrations of H2O2 failed to increase ERK1/2 phosphorylation. Yet, the NADPH oxidase inhibitors diphenyleneiodonium chloride and apocynin blocked both 5-HT-induced PDGFβ receptor phosphorylation and ERK1/2 phosphorylation. The increases in PDGFβ receptor and ERK1/2 phosphorylation were also dependent on protein kinase C activity, likely acting upstream of NADPH oxidase. Additionally, although the ROS scavenger N-acetyl-l-cysteine abrogated 5-HT-induced PDGFβ and TrkB receptor transactivation, it was unable to prevent 5-HT-induced ERK1/2 phosphorylation. Thus, the divergence point for 5-HT-induced receptor tyrosine kinase (RTK) transactivation and ERK1/2 phosphorylation occurs at the level of NADPH oxidase in this system. The ability of 5-HT to induce the production of ROS resulting in transactivation of both PDGFβ and TrkB receptors may suggest that instead of a single GPCR to single RTK pathway, a less selective, more global RTK response to GPCR activation is occurring.
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20
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Abstract
Based on mosaic theory, hypertension is a multifactorial disorder that develops because of genetic, environmental, anatomical, adaptive neural, endocrine, humoral, and hemodynamic factors. It has been recently proposed that oxidative stress may contribute to all of these factors and production of reactive oxygen species (ROS) play an important role in the development of hypertension. Previous studies focusing on the role of vascular NADPH oxidases provided strong support of this concept. Although mitochondria represent one of the most significant sources of cellular ROS generation, the regulation of mitochondrial ROS generation in the cardiovascular system and its pathophysiological role in hypertension are much less understood. In this review, the role of mitochondrial oxidative stress in the pathophysiology of hypertension and cross talk between angiotensin II signaling, pathways involved in mechanotransduction, NADPH oxidases, and mitochondria-derived ROS are considered. The possible benefits of therapeutic strategies that have the potential to attenuate mitochondrial oxidative stress for the prevention/treatment of hypertension are also discussed.
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Affiliation(s)
- Sergey I Dikalov
- Division of Clinical Pharmacology, Free Radicals in Medicine Core, Vanderbilt University Medical Center, Nashville, Tennessee; and
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21
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Beyond retrograde and anterograde signalling: mitochondrial-nuclear interactions as a means for evolutionary adaptation and contemporary disease susceptibility. Biochem Soc Trans 2013; 41:111-7. [PMID: 23356268 DOI: 10.1042/bst20120227] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although there is general agreement that most forms of common disease develop as a consequence of a combination of factors, including genetic, environmental and behavioural contributors, the actual mechanistic basis of how these factors initiate or promote diabetes, cancer, neurodegenerative and cardiovascular diseases in some individuals but not in others with seemingly identical risk factor profiles, is not clearly understood. In this respect, consideration of the potential role for mitochondrial genetics, damage and function in influencing common disease susceptibility seems merited, given that the prehistoric challenges were the original factors that moulded cellular function, and these were based upon the mitochondrial-nuclear relationships that were established during evolutionary history. These interactions were probably refined during prehistoric environmental selection events that, at present, are largely absent. Contemporary risk factors such as diet, sedentary lifestyle and increased longevity, which influence our susceptibility to a variety of chronic diseases were not part of the dynamics that defined the processes of mitochondrial-nuclear interaction, and thus cell function. Consequently, the prehistoric challenges that contributed to cell functionality and evolution should be considered when interpreting and designing experimental data and strategies. Although several molecular epidemiological studies have generally supported this notion, studies that probe beyond these associations are required. Such investigation will mark the initial steps for mechanistically addressing the provocative concept that contemporary human disease susceptibility is the result of prehistoric selection events for mitochondrial-nuclear function, which increased the probability for survival and reproductive success during evolution.
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22
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Shimasaki Y, Pan N, Messina LM, Li C, Chen K, Liu L, Cooper MP, Vita JA, Keaney JF. Uncoupling protein 2 impacts endothelial phenotype via p53-mediated control of mitochondrial dynamics. Circ Res 2013; 113:891-901. [PMID: 23819990 DOI: 10.1161/circresaha.113.301319] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Mitochondria, although required for cellular ATP production, are also known to have other important functions that may include modulating cellular responses to environmental stimuli. However, the mechanisms whereby mitochondria impact cellular phenotype are not yet clear. OBJECTIVE To determine how mitochondria impact endothelial cell function. METHODS AND RESULTS We report here that stimuli for endothelial cell proliferation evoke strong upregulation of mitochondrial uncoupling protein 2 (UCP2). Analysis in silico indicated increased UCP2 expression is common in highly proliferative cell types, including cancer cells. Upregulation of UCP2 was critical for controlling mitochondrial membrane potential (Δψ) and superoxide production. In the absence of UCP2, endothelial growth stimulation provoked mitochondrial network fragmentation and premature senescence via a mechanism involving superoxide-mediated p53 activation. Mitochondrial network fragmentation was both necessary and sufficient for the impact of UCP2 on endothelial cell phenotype. CONCLUSIONS These data identify a novel mechanism whereby mitochondria preserve normal network integrity and impact cell phenotype via dynamic regulation of UCP2.
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Affiliation(s)
- Yukio Shimasaki
- From the Division of Cardiovascular Medicine, Department of Medicine
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23
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Abstract
Protein kinases represent one of the largest families of genes found in eukaryotes. Kinases mediate distinct cellular processes ranging from proliferation, differentiation, survival, and apoptosis. Ligand-mediated activation of receptor kinases can lead to the production of endogenous hydrogen peroxide (H₂O₂) by membrane-bound NADPH oxidases. In turn, H₂O₂ can be utilized as a secondary messenger in signal transduction pathways. This review presents an overview of the molecular mechanisms involved in redox regulation of protein kinases and its effects on signaling cascades. In the first half, we will focus primarily on receptor tyrosine kinases (RTKs), whereas the latter will concentrate on downstream non-receptor kinases involved in relaying stimulant response. Select examples from the literature are used to highlight the functional role of H₂O₂ regarding kinase activity, as well as the components involved in H₂O₂ production and regulation during cellular signaling. In addition, studies demonstrating direct modulation of protein kinases by H₂O₂ through cysteine oxidation will be emphasized. Identification of these redox-sensitive residues may help uncover signaling mechanisms conserved within kinase subfamilies. In some cases, these residues can even be exploited as targets for the development of new therapeutics. Continued efforts in this field will further basic understanding of kinase redox regulation, and delineate the mechanisms involved in physiological and pathological H₂O₂ responses.
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Affiliation(s)
- Thu H Truong
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
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24
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Granados-Cifuentes C, Bellantuono AJ, Ridgway T, Hoegh-Guldberg O, Rodriguez-Lanetty M. High natural gene expression variation in the reef-building coral Acropora millepora: potential for acclimative and adaptive plasticity. BMC Genomics 2013; 14:228. [PMID: 23565725 PMCID: PMC3630057 DOI: 10.1186/1471-2164-14-228] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 02/27/2013] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Ecosystems worldwide are suffering the consequences of anthropogenic impact. The diverse ecosystem of coral reefs, for example, are globally threatened by increases in sea surface temperatures due to global warming. Studies to date have focused on determining genetic diversity, the sequence variability of genes in a species, as a proxy to estimate and predict the potential adaptive response of coral populations to environmental changes linked to climate changes. However, the examination of natural gene expression variation has received less attention. This variation has been implicated as an important factor in evolutionary processes, upon which natural selection can act. RESULTS We acclimatized coral nubbins from six colonies of the reef-building coral Acropora millepora to a common garden in Heron Island (Great Barrier Reef, GBR) for a period of four weeks to remove any site-specific environmental effects on the physiology of the coral nubbins. By using a cDNA microarray platform, we detected a high level of gene expression variation, with 17% (488) of the unigenes differentially expressed across coral nubbins of the six colonies (jsFDR-corrected, p < 0.01). Among the main categories of biological processes found differentially expressed were transport, translation, response to stimulus, oxidation-reduction processes, and apoptosis. We found that the transcriptional profiles did not correspond to the genotype of the colony characterized using either an intron of the carbonic anhydrase gene or microsatellite loci markers. CONCLUSION Our results provide evidence of the high inter-colony variation in A. millepora at the transcriptomic level grown under a common garden and without a correspondence with genotypic identity. This finding brings to our attention the importance of taking into account natural variation between reef corals when assessing experimental gene expression differences. The high transcriptional variation detected in this study is interpreted and discussed within the context of adaptive potential and phenotypic plasticity of reef corals. Whether this variation will allow coral reefs to survive to current challenges remains unknown.
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Affiliation(s)
- Camila Granados-Cifuentes
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Anthony J Bellantuono
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Tyrone Ridgway
- Oceanica Consulting Pty Ltd, PO Box 462, Wembley, WA, 6913, Australia
- The Oceans Institute, University of Western Australia, Crawley, WA, 6009, Australia
| | - Ove Hoegh-Guldberg
- ARC Centre of Excellence for Coral Reef Studies and Coral Genomics Group, School of Pharmacy and Molecular Sciences, James Cook University, Townsville, QLD, Australia
- Global Change Institute, The University of Queensland, St Lucia, QLD, Australia
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25
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Wolf-Goldberg T, Barbul A, Ben-Dov N, Korenstein R. Low electric fields induce ligand-independent activation of EGF receptor and ERK via electrochemical elevation of H(+) and ROS concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1396-408. [PMID: 23481041 DOI: 10.1016/j.bbamcr.2013.02.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 02/11/2013] [Accepted: 02/13/2013] [Indexed: 11/17/2022]
Abstract
Physiological electric fields are involved in many biological processes and known to elicit their effects during long exposures ranging from a few hours to days. Following exposure to electric fields of physiological amplitude, epidermal growth factor receptor (EGFR) was demonstrated to be redistributed and upregulated with further intracellular signaling such as the MAPK signaling cascade. In our study we demonstrated EGFR activation and signaling induced by short train of pulsed low electric field (LEF) (10V/cm, pulse-width 180μs, 500Hz, 2min) in serum-free medium, following 24-hour starvation, and in the absence of exogenous EGF ligand, suggesting a ligand-independent pathway for EGFR activation. This ligandless activation was further confirmed by using neutralizing antibodies (LA1) that block the EGFR ligand-binding site. EGFR activation was found to be EGFR kinase dependent, yet with no dimerization following exposure to LEF. ERK activation was found to be mainly a result of EGFR downstream signaling though it partially occurred via EGFR-independent way. We demonstrate that reactive oxygen species and especially decrease in pH generated during exposure to LEF are involved in EGFR ligandless activation. We propose a possible mechanism for the LEF-induced EGFR ligand-independent activation and show activation of other receptor tyrosine kinases following exposure to LEF.
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Affiliation(s)
- Tami Wolf-Goldberg
- Department of Physiology and Pharmacology, Tel-Aviv University, Tel-Aviv, Israel
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26
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Aragão AZB, Nogueira MLC, Granato DC, Simabuco FM, Honorato RV, Hoffman Z, Yokoo S, Laurindo FRM, Squina FM, Zeri ACM, Oliveira PSL, Sherman NE, Paes Leme AF. Identification of novel interaction between ADAM17 (a disintegrin and metalloprotease 17) and thioredoxin-1. J Biol Chem 2012; 287:43071-82. [PMID: 23105116 PMCID: PMC3522302 DOI: 10.1074/jbc.m112.364513] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 10/24/2012] [Indexed: 12/31/2022] Open
Abstract
ADAM17, which is also known as TNFα-converting enzyme, is the major sheddase for the EGF receptor ligands and is considered to be one of the main proteases responsible for the ectodomain shedding of surface proteins. How a membrane-anchored proteinase with an extracellular catalytic domain can be activated by inside-out regulation is not completely understood. We characterized thioredoxin-1 (Trx-1) as a partner of the ADAM17 cytoplasmic domain that could be involved in the regulation of ADAM17 activity. We induced the overexpression of the ADAM17 cytoplasmic domain in HEK293 cells, and ligands able to bind this domain were identified by MS after protein immunoprecipitation. Trx-1 was also validated as a ligand of the ADAM17 cytoplasmic domain and full-length ADAM17 recombinant proteins by immunoblotting, immunolocalization, and solid phase binding assay. In addition, using nuclear magnetic resonance, it was shown in vitro that the titration of the ADAM17 cytoplasmic domain promotes changes in the conformation of Trx-1. The MS analysis of the cross-linked complexes showed cross-linking between the two proteins by lysine residues. To further evaluate the functional role of Trx-1, we used a heparin-binding EGF shedding cell model and observed that the overexpression of Trx-1 in HEK293 cells could decrease the activity of ADAM17, activated by either phorbol 12-myristate 13-acetate or EGF. This study identifies Trx-1 as a novel interaction partner of the ADAM17 cytoplasmic domain and suggests that Trx-1 is a potential candidate that could be involved in ADAM17 activity regulation.
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Affiliation(s)
- Annelize Z. B. Aragão
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Maria Luiza C. Nogueira
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Daniela C. Granato
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Fernando M. Simabuco
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Rodrigo V. Honorato
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Zaira Hoffman
- the Laboratório Nacional de Ciência e Tecnologia do Bioetanol, CTBE, CNPEM, Campinas, Brasil
| | - Sami Yokoo
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | | | - Fabio M. Squina
- the Laboratório Nacional de Ciência e Tecnologia do Bioetanol, CTBE, CNPEM, Campinas, Brasil
| | - Ana Carolina M. Zeri
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Paulo S. L. Oliveira
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
| | - Nicholas E. Sherman
- the W. M. Keck Biomedical Mass Spectrometry Lab, University of Virginia, Charlottesville, Virginia 22908
| | - Adriana F. Paes Leme
- From the Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, LNBio, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, Brasil
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27
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Higdon AN, Landar A, Barnes S, Darley-Usmar VM. The electrophile responsive proteome: integrating proteomics and lipidomics with cellular function. Antioxid Redox Signal 2012; 17:1580-9. [PMID: 22352679 PMCID: PMC3448939 DOI: 10.1089/ars.2012.4523] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
SIGNIFICANCE The process of lipid peroxidation is emerging as an important mechanism that mediates the post-translational modification of proteins. Through advanced analytical techniques, lipidomics is now emerging as a critical factor in our understanding of the pathology of a broad range of diseases. RECENT ADVANCES During enzymatic or nonenzymatic lipid peroxidation, the simple structure of an unsaturated fatty acid is converted to an oxylipidome, many members of which are electrophilic and form the reactive lipid species (RLS). This aspect of lipid biology is particularly important, as it directly connects lipidomics with proteomics through the post-translational modification of a sub-proteome in the cell. This arises, because the electrophilic members of the oxylipidome react with proteins at nucleophilic amino-acid residues and so change their structure and function to form electrophile-responsive proteomes (ERP). CRITICAL ISSUES Biological systems have relatively few but well-defined and mechanistically distinct pro-oxidant pathways generating RLS. Defining the ERPs and the mechanisms underlying their formation and action has been a major focus for the field of lipidomics and redox signaling. FUTURE DIRECTIONS We propose that a unique oxylipidome can be defined for specific oxidants and will predict the biological responses through the reaction with proteins to form a specific ERP. In this review, we will describe the ERPs that modulate antioxidant and anti-inflammatory protective pathways, including the activation of Keap1/Nrf2 and the promotion of cell death through interactions with mitochondria.
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Affiliation(s)
- Ashlee N Higdon
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Handy DE, Loscalzo J. Redox regulation of mitochondrial function. Antioxid Redox Signal 2012; 16:1323-67. [PMID: 22146081 PMCID: PMC3324814 DOI: 10.1089/ars.2011.4123] [Citation(s) in RCA: 372] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 12/06/2011] [Accepted: 12/06/2011] [Indexed: 02/06/2023]
Abstract
Redox-dependent processes influence most cellular functions, such as differentiation, proliferation, and apoptosis. Mitochondria are at the center of these processes, as mitochondria both generate reactive oxygen species (ROS) that drive redox-sensitive events and respond to ROS-mediated changes in the cellular redox state. In this review, we examine the regulation of cellular ROS, their modes of production and removal, and the redox-sensitive targets that are modified by their flux. In particular, we focus on the actions of redox-sensitive targets that alter mitochondrial function and the role of these redox modifications on metabolism, mitochondrial biogenesis, receptor-mediated signaling, and apoptotic pathways. We also consider the role of mitochondria in modulating these pathways, and discuss how redox-dependent events may contribute to pathobiology by altering mitochondrial function.
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Affiliation(s)
- Diane E Handy
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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29
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Hamilton RT, Walsh ME, Van Remmen H. Mouse Models of Oxidative Stress Indicate a Role for Modulating Healthy Aging. ACTA ACUST UNITED AC 2012; Suppl 4. [PMID: 25300955 DOI: 10.4172/2161-0681.s4-005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Aging is a complex process that affects every major system at the molecular, cellular and organ levels. Although the exact cause of aging is unknown, there is significant evidence that oxidative stress plays a major role in the aging process. The basis of the oxidative stress hypothesis is that aging occurs as a result of an imbalance between oxidants and antioxidants, which leads to the accrual of damaged proteins, lipids and DNA macromolecules with age. Age-dependent increases in protein oxidation and aggregates, lipofuscin, and DNA mutations contribute to age-related pathologies. Many transgenic/knockout mouse models over expressing or deficient in key antioxidant enzymes have been generated to examine the effect of oxidative stress on aging and age-related diseases. Based on currently reported lifespan studies using mice with altered antioxidant defense, there is little evidence that oxidative stress plays a role in determining lifespan. However, mice deficient in antioxidant enzymes are often more susceptible to age-related disease while mice overexpressing antioxidant enzymes often have an increase in the amount of time spent without disease, i.e., healthspan. Thus, by understanding the mechanisms that affect healthy aging, we may discover potential therapeutic targets to extend human healthspan.
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Affiliation(s)
- Ryan T Hamilton
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA ; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA
| | - Michael E Walsh
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA
| | - Holly Van Remmen
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA ; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA ; GRECC, South Texas Veterans Health Care System, San Antonio, TX, USA
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30
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Sheng Y, Stich TA, Barnese K, Gralla EB, Cascio D, Britt RD, Cabelli DE, Valentine JS. Comparison of two yeast MnSODs: mitochondrial Saccharomyces cerevisiae versus cytosolic Candida albicans. J Am Chem Soc 2011; 133:20878-89. [PMID: 22077216 PMCID: PMC3268005 DOI: 10.1021/ja2077476] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human MnSOD is significantly more product-inhibited than bacterial MnSODs at high concentrations of superoxide (O(2)(-)). This behavior limits the amount of H(2)O(2) produced at high [O(2)(-)]; its desirability can be explained by the multiple roles of H(2)O(2) in mammalian cells, particularly its role in signaling. To investigate the mechanism of product inhibition in MnSOD, two yeast MnSODs, one from Saccharomyces cerevisiae mitochondria (ScMnSOD) and the other from Candida albicans cytosol (CaMnSODc), were isolated and characterized. ScMnSOD and CaMnSODc are similar in catalytic kinetics, spectroscopy, and redox chemistry, and they both rest predominantly in the reduced state (unlike most other MnSODs). At high [O(2)(-)], the dismutation efficiencies of the yeast MnSODs surpass those of human and bacterial MnSODs, due to very low level of product inhibition. Optical and parallel-mode electron paramagnetic resonance (EPR) spectra suggest the presence of two Mn(3+) species in yeast Mn(3+)SODs, including the well-characterized 5-coordinate Mn(3+) species and a 6-coordinate L-Mn(3+) species with hydroxide as the putative sixth ligand (L). The first and second coordination spheres of ScMnSOD are more similar to bacterial than to human MnSOD. Gln154, an H-bond donor to the Mn-coordinated solvent molecule, is slightly further away from Mn in yeast MnSODs, which may result in their unusual resting state. Mechanistically, the high efficiency of yeast MnSODs could be ascribed to putative translocation of an outer-sphere solvent molecule, which could destabilize the inhibited complex and enhance proton transfer from protein to peroxide. Our studies on yeast MnSODs indicate the unique nature of human MnSOD in that it predominantly undergoes the inhibited pathway at high [O(2)(-)].
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Affiliation(s)
- Yuewei Sheng
- Department of Chemistry and Biochemistry, University of California Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - Troy A. Stich
- Department of Chemistry, University of California Davis, One Shields Avenue, Davis, California 95616, USA
| | - Kevin Barnese
- Department of Chemistry and Biochemistry, University of California Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - Edith B. Gralla
- Department of Chemistry and Biochemistry, University of California Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - Duilio Cascio
- Department of Energy-Institute for Genomics and Proteomics, University of California Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - R. David Britt
- Department of Chemistry, University of California Davis, One Shields Avenue, Davis, California 95616, USA
| | - Diane E. Cabelli
- Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Joan Selverstone Valentine
- Department of Chemistry and Biochemistry, University of California Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
- Department of Bioinspired Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
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31
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Dikalov S. Cross talk between mitochondria and NADPH oxidases. Free Radic Biol Med 2011; 51:1289-301. [PMID: 21777669 PMCID: PMC3163726 DOI: 10.1016/j.freeradbiomed.2011.06.033] [Citation(s) in RCA: 607] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/27/2011] [Accepted: 06/29/2011] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) play an important role in physiological and pathological processes. In recent years, a feed-forward regulation of the ROS sources has been reported. The interactions between the main cellular sources of ROS, such as mitochondria and NADPH oxidases, however, remain obscure. This work summarizes the latest findings on the role of cross talk between mitochondria and NADPH oxidases in pathophysiological processes. Mitochondria have the highest levels of antioxidants in the cell and play an important role in the maintenance of cellular redox status, thereby acting as an ROS and redox sink and limiting NADPH oxidase activity. Mitochondria, however, are not only a target for ROS produced by NADPH oxidase but also a significant source of ROS, which under certain conditions may stimulate NADPH oxidases. This cross talk between mitochondria and NADPH oxidases, therefore, may represent a feed-forward vicious cycle of ROS production, which can be pharmacologically targeted under conditions of oxidative stress. It has been demonstrated that mitochondria-targeted antioxidants break this vicious cycle, inhibiting ROS production by mitochondria and reducing NADPH oxidase activity. This may provide a novel strategy for treatment of many pathological conditions including aging, atherosclerosis, diabetes, hypertension, and degenerative neurological disorders in which mitochondrial oxidative stress seems to play a role. It is conceivable that the use of mitochondria-targeted treatments would be effective in these conditions.
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Affiliation(s)
- Sergey Dikalov
- Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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32
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Mitofusins are required for angiogenic function and modulate different signaling pathways in cultured endothelial cells. J Mol Cell Cardiol 2011; 51:885-93. [PMID: 21839087 DOI: 10.1016/j.yjmcc.2011.07.023] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/25/2011] [Accepted: 07/26/2011] [Indexed: 12/21/2022]
Abstract
The mitofusin proteins MFN1 and MFN2 function to maintain mitochondrial networks by binding one another and initiating outer mitochondrial membrane fusion. While it has recently been recognized that vascular endothelial cells rely upon mitochondria as signaling rather than energy-producing moieties, the role of mitochondrial dynamics in endothelial cell function has not been addressed. To begin to understand what role mitochondrial dynamics play in this context, we examined the regulation of MFN1 and MFN2 and the consequences of siRNA-mediated knockdown of these proteins in cultured endothelial cells. Treatment with VEGF-A led to the upregulation of MFN2 and, to a lesser extent, MFN1. Knockdown of either MFN led to disrupted mitochondrial networks and diminished mitochondrial membrane potential. Knockdown of either MFN decreased VEGF-mediated migration and differentiation into network structures. MFN ablation also diminished endothelial cell viability and increased apoptosis under low mitogen conditions. Knockdown of MFN2 uniquely resulted in a decrease in the generation of reactive oxygen species as well as the blunting of the gene expression of components of the respiratory chain and transcription factors associated with oxidative metabolism. In contrast, ablation of MFN1 led to the selective reduction of VEGF-stimulated Akt-eNOS signaling. Taken together, our data indicate that mitochondrial dynamics, particularly those mediated by the mitofusins, play a role in endothelial cell function and viability.
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33
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Krzywanski DM, Moellering DR, Fetterman JL, Dunham-Snary KJ, Sammy MJ, Ballinger SW. The mitochondrial paradigm for cardiovascular disease susceptibility and cellular function: a complementary concept to Mendelian genetics. J Transl Med 2011; 91:1122-35. [PMID: 21647091 PMCID: PMC3654682 DOI: 10.1038/labinvest.2011.95] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
While there is general agreement that cardiovascular disease (CVD) development is influenced by a combination of genetic, environmental, and behavioral contributors, the actual mechanistic basis of how these factors initiate or promote CVD development in some individuals while others with identical risk profiles do not, is not clearly understood. This review considers the potential role for mitochondrial genetics and function in determining CVD susceptibility from the standpoint that the original features that molded cellular function were based upon mitochondrial-nuclear relationships established millions of years ago and were likely refined during prehistoric environmental selection events that today, are largely absent. Consequently, contemporary risk factors that influence our susceptibility to a variety of age-related diseases, including CVD were probably not part of the dynamics that defined the processes of mitochondrial-nuclear interaction, and thus, cell function. In this regard, the selective conditions that contributed to cellular functionality and evolution should be given more consideration when interpreting and designing experimental data and strategies. Finally, future studies that probe beyond epidemiologic associations are required. These studies will serve as the initial steps for addressing the provocative concept that contemporary human disease susceptibility is the result of selection events for mitochondrial function that increased chances for prehistoric human survival and reproductive success.
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Affiliation(s)
- David M Krzywanski
- Division of Molecular and Cellular Pathology, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL, USA
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34
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Wang Y, Zang QS, Liu Z, Wu Q, Maass D, Dulan G, Shaul PW, Melito L, Frantz DE, Kilgore JA, Williams NS, Terada LS, Nwariaku FE. Regulation of VEGF-induced endothelial cell migration by mitochondrial reactive oxygen species. Am J Physiol Cell Physiol 2011; 301:C695-704. [PMID: 21653897 DOI: 10.1152/ajpcell.00322.2010] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial migration is a crucial aspect of a variety of physiologic and pathologic conditions including atherosclerosis and vascular repair. Reactive oxygen species (ROS) function as second messengers during endothelial migration. Multiple intracellular sources of ROS are regulated by cellular context, external stimulus, and the microenvironment. However, the predominant source of ROS during endothelial cell (EC) migration and the mechanisms by which ROS regulate cell migration are incompletely understood. In this study, we tested the hypothesis that mitochondria-derived ROS (mtROS) regulate EC migration. In cultured human umbilical vein endothelial cells, VEGF increased mitochondrial metabolism, promoted mtROS production, and induced cell migration. Either the targeted mitochondrial delivery of the antioxidant, vitamin E (Mito-Vit-E), or the depletion of mitochondrial DNA abrogated VEGF-mediated mtROS production. Overexpression of mitochondrial catalase also inhibited VEGF-induced mitochondrial metabolism, Rac activation, and cell migration. Furthermore, these interventions suppressed VEGF-stimulated EC migration and blocked Rac1 activation in endothelial cells. Constitutively active Rac1 reversed Mito-Vit-E-induced inhibition of EC migration. Mito-Vit-E also attenuated carotid artery reendothelialization in vivo. These results provide strong evidence that mtROS regulate EC migration through Rac-1.
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Affiliation(s)
- Youxue Wang
- Dept. of Surgery, The Univ. of Texas Southwestern Medical Cente at Dallas, 75390-9156, USA
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35
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World C, Spindel ON, Berk BC. Thioredoxin-interacting protein mediates TRX1 translocation to the plasma membrane in response to tumor necrosis factor-α: a key mechanism for vascular endothelial growth factor receptor-2 transactivation by reactive oxygen species. Arterioscler Thromb Vasc Biol 2011; 31:1890-7. [PMID: 21636804 DOI: 10.1161/atvbaha.111.226340] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Thioredoxin-interacting protein (TXNIP) promotes inflammation in endothelial cells (EC) by binding to thioredoxin-1 (TRX1) in a redox-dependent manner. Formation of the TXNIP-TRX1 complex relieves inhibition of the apoptosis signal-regulating kinase 1-c-Jun N-terminal kinase-vascular cell adhesion molecule-1 pathway. Because TXNIP is an α-arrestin with numerous protein-protein interacting domains, we hypothesized that TXNIP-TRX1 trafficking should alter function of EC exposed to reactive oxygen species (ROS). METHODS AND RESULTS In response to physiological levels of ROS (10 ng/mL tumor necrosis factor-α and 30 μmol/L H(2)O(2)), TXNIP-TRX1 translocated to the plasma membrane in human umbilical vein EC, with a peak at 30 minutes, as measured by immunofluorescence colocalization with vascular endothelial-cadherin, cell fractionation, and membrane sheet assay. TXNIP-mediated translocation of TRX1 to the membrane required TXNIP and TRX1 binding, as evidenced by inability of the ROS-insensitive TXNIP-Cys247Ser mutant to promote membrane localization. Vascular endothelial growth factor signaling required TXNIP, as shown by significant decreases in plasma membrane tyrosine phosphorylation and EC migration after TRX1 knockdown. Furthermore, TXNIP knockdown increased human umbilical vein EC apoptosis induced by tumor necrosis factor. Rescue with TXNIP-wild-type but not TXNIP-Cys247Ser prevented cell death. CONCLUSIONS These findings suggest a novel role for the TXNIP-TRX1 complex to enable inflammation by promoting EC survival and vascular endothelial growth factor signaling under conditions of physiological oxidative stress.
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Affiliation(s)
- Cameron World
- Department of Medicine, University of Rochester School of Medicine and Dentistry, NY 14642, USA
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36
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van Horssen J, Witte ME, Schreibelt G, de Vries HE. Radical changes in multiple sclerosis pathogenesis. Biochim Biophys Acta Mol Basis Dis 2011; 1812:141-50. [DOI: 10.1016/j.bbadis.2010.06.011] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 06/08/2010] [Accepted: 06/16/2010] [Indexed: 12/20/2022]
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Verschoor ML, Wilson LA, Singh G. Mechanisms associated with mitochondrial-generated reactive oxygen species in cancer. Can J Physiol Pharmacol 2011; 88:204-19. [PMID: 20393586 DOI: 10.1139/y09-135] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mitochondria are unique cellular organelles that contain their own genome and, in conjunction with the nucleus, are able to transcribe and translate genes encoding components of the electron transport chain (ETC). To do so, the mitochondria must communicate with the nucleus via the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), which are produced as a byproduct of aerobic respiration within the mitochondria. Mitochondrial signaling is proposed to be altered in cancer cells, where the mitochondria are frequently found to harbor mutations within their genome and display altered functional characteristics leading to increased glycolysis. As signaling molecules, ROS oxidize and inhibit MAPK phosphatases resulting in enhanced proliferation and survival, an effect particularly advantageous to cancer cells. In terms of transcriptional regulation, ROS affect the phosphorylation, activation, oxidation, and DNA binding of transcription factors such as AP-1, NF-kappaB, p53, and HIF-1alpha, leading to changes in target gene expression. Increased ROS production by defective cancer cell mitochondria also results in the upregulation of the transcription factor Ets-1, a factor that has been increasingly associated with aggressive cancers.
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Affiliation(s)
- Meghan L Verschoor
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada
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38
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Myers TJ, Brennaman LH, Stevenson M, Higashiyama S, Russell WE, Lee DC, Sunnarborg SW. Mitochondrial reactive oxygen species mediate GPCR-induced TACE/ADAM17-dependent transforming growth factor-alpha shedding. Mol Biol Cell 2010; 20:5236-49. [PMID: 19846666 DOI: 10.1091/mbc.e08-12-1256] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) activation by GPCRs regulates many important biological processes. ADAM metalloprotease activity has been implicated as a key step in transactivation, yet the regulatory mechanisms are not fully understood. Here, we investigate the regulation of transforming growth factor-alpha (TGF-alpha) shedding by reactive oxygen species (ROS) through the ATP-dependent activation of the P2Y family of GPCRs. We report that ATP stimulates TGF-alpha proteolysis with concomitant EGFR activation and that this process requires TACE/ADAM17 activity in both murine fibroblasts and CHO cells. ATP-induced TGF-alpha shedding required calcium and was independent of Src family kinases and PKC and MAPK signaling. Moreover, ATP-induced TGF-alpha shedding was completely inhibited by scavengers of ROS, whereas calcium-stimulated shedding was partially inhibited by ROS scavenging. Hydrogen peroxide restored TGF-alpha shedding after calcium chelation. Importantly, we also found that ATP-induced shedding was independent of the cytoplasmic NADPH oxidase complex. Instead, mitochondrial ROS production increased in response to ATP and mitochondrial oxidative complex activity was required to activate TACE-dependent shedding. These results reveal an essential role for mitochondrial ROS in regulating GPCR-induced growth factor shedding.
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Affiliation(s)
- Timothy J Myers
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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39
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Tabit CE, Chung WB, Hamburg NM, Vita JA. Endothelial dysfunction in diabetes mellitus: molecular mechanisms and clinical implications. Rev Endocr Metab Disord 2010; 11:61-74. [PMID: 20186491 PMCID: PMC2882637 DOI: 10.1007/s11154-010-9134-4] [Citation(s) in RCA: 384] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiovascular disease is a major complication of diabetes mellitus, and improved strategies for prevention and treatment are needed. Endothelial dysfunction contributes to the pathogenesis and clinical expression of atherosclerosis in diabetes mellitus. This article reviews the evidence linking endothelial dysfunction to human diabetes mellitus and experimental studies that investigated the responsible mechanisms. We then discuss the implications of these studies for current management and for new approaches for the prevention and treatment of cardiovascular disease in patients with diabetes mellitus.
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Affiliation(s)
- Corey E. Tabit
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - William B. Chung
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Naomi M. Hamburg
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Joseph A. Vita
- Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
- Section of Cardiology, Boston Medical Center, 88 East Newton Street, Boston, MA 02118, USA,
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40
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Galganska H, Karachitos A, Wojtkowska M, Stobienia O, Budzinska M, Kmita H. Communication between mitochondria and nucleus: putative role for VDAC in reduction/oxidation mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1276-80. [PMID: 20144586 DOI: 10.1016/j.bbabio.2010.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/01/2010] [Accepted: 02/01/2010] [Indexed: 02/04/2023]
Abstract
Voltage dependent anion channel (VDAC) was identified in 1976 and since that time has been extensively studied. It is well known that VDAC transports metabolites across the outer mitochondrial membrane. The simple transport function is indispensable for proper mitochondria functions and, consequently for cell activity, and makes VDAC crucial for a range of cellular processes including ATP rationing, Ca2+ homeostasis and apoptosis execution. Here, we review recent data obtained for Saccharomyces cerevisiae cells used as a model system concerning the putative role of VDAC in communication between mitochondria and the nucleus. The S. cerevisiae VDAC isoform known as VDAC1 (termed here YVDAC) mediates the cytosol reduction/oxidation (redox) state that contributes to regulation of expression and activity of cellular proteins including proteins that participate in protein import into mitochondria and antioxidant enzymes. Simultaneously, copper-and-zinc-containing superoxide dismutase (CuZnSOD) plays an important role in controlling YVDAC activity and expression levels. Thus, it is proposed that VDAC constitutes an important component of a regulatory mechanism based on the cytosol redox state.
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Affiliation(s)
- Hanna Galganska
- Laboratory of Bioenergetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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41
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Mitochondrial peroxiredoxin involvement in antioxidant defence and redox signalling. Biochem J 2009; 425:313-25. [PMID: 20025614 DOI: 10.1042/bj20091541] [Citation(s) in RCA: 375] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Prxs (peroxiredoxins) are a family of proteins that are extremely effective at scavenging peroxides. The Prxs exhibit a number of intriguing properties that distinguish them from conventional antioxidants, including a susceptibility to inactivation by hyperoxidation in the presence of excess peroxide and the ability to form complex oligomeric structures. These properties, combined with a high cellular abundance and reactivity with hydrogen peroxide, have led to speculation that the Prxs function as redox sensors that transmit signals as part of the cellular response to oxidative stress. Multicellular organisms express several different Prxs that can be categorized by their subcellular distribution. In mammals, Prx 3 and Prx 5 are targeted to the mitochondrial matrix. Mitochondria are a major source of hydrogen peroxide, and this oxidant is implicated in the damage associated with aging and a number of pathologies. Hydrogen peroxide can also act as a second messenger, and is linked with signalling events in mitochondria, including the induction of apoptosis. A simple kinetic competition analysis estimates that Prx 3 will be the target for up to 90% of hydrogen peroxide generated in the matrix. Therefore, mitochondrial Prxs have the potential to play a major role in mitochondrial redox signalling, but the extent of this role and the mechanisms involved are currently unclear.
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42
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Zemlyak I, Sapolsky R, Gozes I. NAP protects against cyanide-related microtubule destruction. J Neural Transm (Vienna) 2009; 116:1411-6. [DOI: 10.1007/s00702-009-0252-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Accepted: 05/29/2009] [Indexed: 11/28/2022]
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Wosniak J, Santos CXC, Kowaltowski AJ, Laurindo FRM. Cross-talk between mitochondria and NADPH oxidase: effects of mild mitochondrial dysfunction on angiotensin II-mediated increase in Nox isoform expression and activity in vascular smooth muscle cells. Antioxid Redox Signal 2009; 11:1265-78. [PMID: 19281299 DOI: 10.1089/ars.2009.2392] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondria and NADPH oxidase activation are concomitantly involved in pathogenesis of many vascular diseases. However, possible cross-talk between those ROS-generating systems is unclear. We induced mild mitochondrial dysfunction due to mitochondrial DNA damage after 24 h incubation of rabbit aortic smooth muscle (VSMC) with 250 ng/mL ethidium bromide (EtBr). VSMC remained viable and had 29% less oxygen consumption, 16% greater baseline hydrogen peroxide, and unchanged glutathione levels. Serum-stimulated proliferation was unaltered at 24 h. Although PCR amplification of several mtDNA sequences was preserved, D-Loop mtDNA region showed distinct amplification of shorter products after EtBr. Such evidence for DNA damage was further enhanced after angiotensin-II (AngII) incubation. Remarkably, the normally observed increase in VSMC membrane fraction NADPH oxidase activity after AngII was completely abrogated after EtBr, together with failure to upregulate Nox1 mRNA expression. Conversely, basal Nox4 mRNA expression increased 1.6-fold, while being unresponsive to AngII. Similar loss in AngII redox response occurred after 24 h antimycin-A incubation. Enhanced Nox4 expression was unassociated with endoplasmic reticulum stress markers. Protein disulfide isomerase, an NADPH oxidase regulator, exhibited increased expression and inverted pattern of migration to membrane fraction after EtBr. These results unravel functionally relevant cross-talk between mitochondria and NADPH oxidase, which markedly affects redox responses to AngII.
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Affiliation(s)
- João Wosniak
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo School of Medicine, São Paulo, Brazil
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44
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Fearon IM, Faux SP. Oxidative stress and cardiovascular disease: novel tools give (free) radical insight. J Mol Cell Cardiol 2009; 47:372-81. [PMID: 19481547 DOI: 10.1016/j.yjmcc.2009.05.013] [Citation(s) in RCA: 228] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 05/12/2009] [Accepted: 05/20/2009] [Indexed: 02/07/2023]
Abstract
Cardiovascular disease is the most common cause of mortality in the Western world and accounts for up to a third of all deaths worldwide. Cardiovascular disease is multifactorial and involves complex interplay between lifestyle (diet, smoking, exercise, ethanol consumption) and fixed (genotype, age, menopausal status, gender) causative factors. The initiating step in cardiovascular disease is endothelial damage, which exposes these cells and the underlying cell layers to a deleterious inflammatory process which ultimately leads to the formation of atherosclerotic lesions. Intrinsic to lesion formation is cellular oxidative stress, due to the production of damaging free radicals (reactive oxygen and nitrogen species) by many cell types including endothelial cells, vascular smooth muscle cells and monocytes/macrophages. Exogenous factors such as smoking and the existence of other disease states such as diabetes also contribute to oxidative stress and are strong risk factors for cardiovascular disease. In this review we describe this role of free radicals in atherosclerosis and discuss the mechanisms and cellular systems by which these radicals are produced. We also highlight recent technological advances which have added to the vascular biologist's armoury and which promise to provide new insight into the role of reactive oxygen species in cardiovascular disease.
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Affiliation(s)
- Ian M Fearon
- British American Tobacco, Group R & D, Southampton, SO15 8TL, UK.
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Bashan N, Kovsan J, Kachko I, Ovadia H, Rudich A. Positive and negative regulation of insulin signaling by reactive oxygen and nitrogen species. Physiol Rev 2009; 89:27-71. [PMID: 19126754 DOI: 10.1152/physrev.00014.2008] [Citation(s) in RCA: 351] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Regulated production of reactive oxygen species (ROS)/reactive nitrogen species (RNS) adequately balanced by antioxidant systems is a prerequisite for the participation of these active substances in physiological processes, including insulin action. Yet, increasing evidence implicates ROS and RNS as negative regulators of insulin signaling, rendering them putative mediators in the development of insulin resistance, a common endocrine abnormality that accompanies obesity and is a risk factor of type 2 diabetes. This review deals with this dual, seemingly contradictory, function of ROS and RNS in regulating insulin action: the major processes for ROS and RNS generation and detoxification are presented, and a critical review of the evidence that they participate in the positive and negative regulation of insulin action is provided. The cellular and molecular mechanisms by which ROS and RNS are thought to participate in normal insulin action and in the induction of insulin resistance are then described. Finally, we explore the potential usefulness and the challenges in modulating the oxidant-antioxidant balance as a potentially promising, but currently disappointing, means of improving insulin action in insulin resistance-associated conditions, leading causes of human morbidity and mortality of our era.
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Affiliation(s)
- Nava Bashan
- Department of Clinical Biochemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Zmijewski JW, Lorne E, Banerjee S, Abraham E. Participation of mitochondrial respiratory complex III in neutrophil activation and lung injury. Am J Physiol Lung Cell Mol Physiol 2009; 296:L624-34. [PMID: 19168575 DOI: 10.1152/ajplung.90522.2008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Reactive oxygen species (ROS) produced during mitochondrial activity participate in the regulation of intracellular signaling pathways. However, there is only limited information concerning the role that ROS derived from the mitochondrial respiratory chain play in modulating neutrophil activity and participation in acute inflammatory processes. Because mitochondrial complex III is a major site of ROS formation, we examined whether selective complex III inhibition, through exposure of neutrophils to myxothiazol or antimycin A, would affect LPS-induced activation. Culture of neutrophils with antimycin A or myxothiazol resulted in increased intracellular levels of ROS, including superoxide and hydrogen peroxide (H(2)O(2)). Inhibition of complex III activity reduced LPS-induced degradation of IkappaB-alpha, nuclear accumulation of NF-kappaB, and proinflammatory cytokine production. The effects of antimycin A or myxothiazol appeared to be dependent on generation of H(2)O(2) since addition of pegylated catalase to neutrophils restored LPS-mediated IkappaB-alpha degradation and production of proinflammatory cytokines. Administration of myxothiazol to mice resulted in diminished mitochondrial complex III activity in the lungs and decreased severity of LPS-induced lung injury. These results indicate that inhibition of mitochondrial complex III diminishes Toll-like receptor 4-induced neutrophil activation through a mechanism dependent on H(2)O(2) generation and also reduces the severity of lung injury due to LPS exposure, a pathophysiologic process in which neutrophils play a major role.
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Affiliation(s)
- Jaroslaw W Zmijewski
- Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294-0012, USA
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EGb761 protects hydrogen peroxide-induced death of spinal cord neurons through inhibition of intracellular ROS production and modulation of apoptotic regulating genes. J Mol Neurosci 2009; 38:103-13. [PMID: 19148782 DOI: 10.1007/s12031-008-9140-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 07/29/2008] [Indexed: 10/21/2022]
Abstract
The present study was conducted to investigate whether Ginkgo biloba extract (EGb) 761 could protect spinal cord neurons from H(2)O(2)-induced toxicity. In primary spinal cord neurons isolated from embryonic day 14 rats, H(2)O(2) administration resulted in a significant decrease in the survival of spinal cord neurons. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and Hoechst 33342 nuclear staining showed that these cells die by apoptosis. Such neuronal death, however, was significantly reversed by EGb761 in a dose-dependent manner. Moreover, a marked increase in intracellular free radical generation was found after the H(2)O(2) administration which could be reversed almost completely by EGb761, indicating that inhibition of free radical generation is an important mechanism of the anti-apoptosis action of EGb761. Finally, treatment of cells with H(2)O(2) for 12 h reduced the expression of Bcl-2, an anti-apoptotic gene, by 70% but showed no effect on the level of Bax, a pro-apoptotic gene. EGb76 treatment, however, significantly reversed H(2)O(2)-induced reduction of Bcl-2 expression and inhibited Bax expression by 2.3-fold. Thus, our study provided evidence showing that the protective effect of EGb761 on spinal cord neuronal apoptosis after oxidative stress is mediated, at least in part, by its anti-oxidative action and regulation of apoptosis-related genes Bcl-2 and Bax.
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Schulz E, Dopheide J, Schuhmacher S, Thomas SR, Chen K, Daiber A, Wenzel P, Münzel T, Keaney JF. Suppression of the JNK pathway by induction of a metabolic stress response prevents vascular injury and dysfunction. Circulation 2008; 118:1347-57. [PMID: 18809807 DOI: 10.1161/circulationaha.108.784298] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Oxidative injury and dysfunction of the vascular endothelium are early and causal features of many vascular diseases. Single antioxidant strategies to prevent vascular injury have met with mixed results. METHODS AND RESULTS Here, we report that induction of a metabolic stress response with adenosine monophosphate kinase (AMPK) prevents oxidative endothelial cell injury. This response is characterized by stabilization of the mitochondrion and increased mitochondrial biogenesis, resulting in attenuation of oxidative c-Jun N-terminal kinase (JNK) activation. We report that peroxisome proliferator coactivator 1alpha is a key downstream target of AMPK that is both necessary and sufficient for the metabolic stress response and JNK attenuation. Moreover, induction of the metabolic stress response in vivo attenuates reactive oxygen species-mediated JNK activation and endothelial dysfunction in response to angiotensin II in wild-type mice but not in animals lacking either the endothelial isoform of AMPK or peroxisome proliferator coactivator 1alpha. CONCLUSIONS These data highlight AMPK and peroxisome proliferator coactivator 1alpha as potential therapeutic targets for the amelioration of endothelial dysfunction and, as a consequence, vascular disease.
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Affiliation(s)
- Eberhard Schulz
- Department of Cardiology, 2nd Medical Clinic of the University Hospital Mainz, Johannes Gutenberg University, Mainz, Germany.
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Thomas SR, Witting PK, Drummond GR. Redox control of endothelial function and dysfunction: molecular mechanisms and therapeutic opportunities. Antioxid Redox Signal 2008; 10:1713-65. [PMID: 18707220 DOI: 10.1089/ars.2008.2027] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The endothelium is essential for the maintenance of vascular homeostasis. Central to this role is the production of endothelium-derived nitric oxide (EDNO), synthesized by the endothelial isoform of nitric oxide synthase (eNOS). Endothelial dysfunction, manifested as impaired EDNO bioactivity, is an important early event in the development of various vascular diseases, including hypertension, diabetes, and atherosclerosis. The degree of impairment of EDNO bioactivity is a determinant of future vascular complications. Accordingly, growing interest exists in defining the pathologic mechanisms involved. Considerable evidence supports a causal role for the enhanced production of reactive oxygen species (ROS) by vascular cells. ROS directly inactivate EDNO, act as cell-signaling molecules, and promote protein dysfunction, events that contribute to the initiation and progression of endothelial dysfunction. Increasing data indicate that strategies designed to limit vascular ROS production can restore endothelial function in humans with vascular complications. The purpose of this review is to outline the various ways in which ROS can influence endothelial function and dysfunction, describe the redox mechanisms involved, and discuss approaches for preventing endothelial dysfunction that may highlight future therapeutic opportunities in the treatment of cardiovascular disease.
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Affiliation(s)
- Shane R Thomas
- Centre for Vascular Research, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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Piantadosi CA. Carbon monoxide, reactive oxygen signaling, and oxidative stress. Free Radic Biol Med 2008; 45:562-9. [PMID: 18549826 PMCID: PMC2570053 DOI: 10.1016/j.freeradbiomed.2008.05.013] [Citation(s) in RCA: 200] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2007] [Revised: 05/14/2008] [Accepted: 05/15/2008] [Indexed: 11/22/2022]
Abstract
The ubiquitous gas, carbon monoxide (CO), is of substantial biological importance, but apart from its affinity for reduced transition metals, particularly heme-iron, it is surprisingly nonreactive-as is the ferrous-carbonyl-in living systems. CO does form strong complexes with heme proteins for which molecular O2 is the preferred ligand and to which are attributed diverse physiological, adaptive, and toxic effects. Lately, it has become apparent that both exogenous and endogenous CO produced by heme oxygenase engender a prooxidant milieu in aerobic mammalian cells which initiates signaling related to reactive oxygen species (ROS) generation. ROS signaling contingent on CO can be segregated by CO concentration-time effects on cellular function, by the location of heme proteins, e.g., mitochondrial or nonmitochondrial sites, or by specific oxidation-reduction (redox) reactions. The fundamental responses to CO involve overt physiological regulatory events, such as activation of redox-sensitive transcription factors or stress-activated kinases, which institute compensatory expression of antioxidant enzymes and other adaptations to oxidative stress. In contrast, responses originating from highly elevated or protracted CO exposures tend to be nonspecific, produce untoward biological oxidations, and interfere with homeostasis. This brief overview provides a conceptual framework for understanding CO biology in terms of this physiological-pathological hierarchy.
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Affiliation(s)
- Claude A Piantadosi
- Department of Medicine, Duke University Medical Center, Box 3315 CR II Building White Zone, Trent Drive, Durham, NC 27710, USA.
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