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Patel A, Simkulet M, Maity S, Venkatesan M, Matzavinos A, Madesh M, Alevriadou BR. The mitochondrial Ca 2+ uniporter channel synergizes with fluid shear stress to induce mitochondrial Ca 2+ oscillations. Sci Rep 2022; 12:21161. [PMID: 36476944 PMCID: PMC9729216 DOI: 10.1038/s41598-022-25583-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
The mitochondrial calcium (Ca2+) uniporter (MCU) channel is responsible for mitochondrial Ca2+ influx. Its expression was found to be upregulated in endothelial cells (ECs) under cardiovascular disease conditions. Since the role of MCU in regulating cytosolic Ca2+ homeostasis in ECs exposed to shear stress (SS) is unknown, we studied mitochondrial Ca2+ dynamics (that is known to decode cytosolic Ca2+ signaling) in sheared ECs. To understand cause-and-effect, we ectopically expressed MCU in ECs. A higher percentage of MCU-transduced ECs exhibited mitochondrial Ca2+ transients/oscillations, and at higher frequency, under SS compared to sheared control ECs. Transients/oscillations correlated with mitochondrial reactive oxygen species (mROS) flashes and mitochondrial membrane potential (ΔΨm) flickers, and depended on activation of the mechanosensitive Piezo1 channel and the endothelial nitric oxide synthase (eNOS). A positive feedback loop composed of mitochondrial Ca2+ uptake/mROS flashes/ΔΨm flickers and endoplasmic reticulum Ca2+ release, in association with Piezo1 and eNOS, provided insights into the mechanism by which SS, under conditions of high MCU activity, may shape vascular EC energetics and function.
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Affiliation(s)
- Akshar Patel
- grid.273335.30000 0004 1936 9887Vascular Mechanobiology Laboratory, Department of Biomedical Engineering, and Center for Cell, Gene, and Tissue Engineering, University at Buffalo – The State University of New York, Buffalo, NY 14260 USA
| | - Matthew Simkulet
- grid.273335.30000 0004 1936 9887Vascular Mechanobiology Laboratory, Department of Biomedical Engineering, and Center for Cell, Gene, and Tissue Engineering, University at Buffalo – The State University of New York, Buffalo, NY 14260 USA
| | - Soumya Maity
- grid.267309.90000 0001 0629 5880Center for Mitochondrial Medicine, Department of Medicine, University of Texas Health San Antonio, San Antonio, TX 78229 USA
| | - Manigandan Venkatesan
- grid.267309.90000 0001 0629 5880Center for Mitochondrial Medicine, Department of Medicine, University of Texas Health San Antonio, San Antonio, TX 78229 USA
| | - Anastasios Matzavinos
- grid.7870.80000 0001 2157 0406Institute for Mathematical and Computational Engineering, Pontifical Catholic University of Chile, Santiago, Chile
| | - Muniswamy Madesh
- grid.267309.90000 0001 0629 5880Center for Mitochondrial Medicine, Department of Medicine, University of Texas Health San Antonio, San Antonio, TX 78229 USA
| | - B. Rita Alevriadou
- grid.273335.30000 0004 1936 9887Vascular Mechanobiology Laboratory, Department of Biomedical Engineering, and Center for Cell, Gene, and Tissue Engineering, University at Buffalo – The State University of New York, Buffalo, NY 14260 USA
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VIP Stabilizes the Cytoskeleton of Schlemm's Canal Endothelia via Reducing Caspase-3 Mediated ZO-1 Endolysosomal Degradation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:9397960. [PMID: 34552687 PMCID: PMC8452417 DOI: 10.1155/2021/9397960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/05/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022]
Abstract
Objectives In glaucomatous eyes, the main aqueous humor (AH) outflow pathway is damaged by accumulated oxidative stress arising from the microenvironment, vascular dysregulation, and aging, which results in increased outflow resistance and ocular hypertension. Schlemm's canal (SC) serves as the final filtration barrier of the main AH outflow pathway. The present study is aimed at investigating the possible regulation of vasoactive intestinal peptide (VIP) on the cytoskeleton by stabilizing ZO-1 in SC. Methods Model of chronic ocular hypertension (COH) induced by episcleral venous cauterization was treated with topical VIP. The ultrastructure of junctions, ZO-1 levels, and permeability of the SC inner wall to FITC-dextran (70 kDa) were detected in the COH models. The F-actin distribution, F/G-actin ratio, and ZO-1 degradation pathway in human umbilical vein endothelial cells (HUVECs) and HEK 293 cells were investigated. Results ZO-1 in the outer wall of the SC was less than that in the inner wall. COH elicited junction disruption, ZO-1 reduction, and increased permeability of the SC inner wall to FITC-dextran in rats. ZO-1 plays an essential role in maintaining the F/G-actin ratio and F-actin distribution. VIP treatment attenuated the downregulation of ZO-1 associated with COH or H2O2-induced oxidative damage. In H2O2-stimulated HUVECs, the caspase-3 inhibitor prevents ZO-1 disruption. Caspase-3 activation promoted endolysosomal degradation of ZO-1. Furthermore, a decrease in caspase-3 activation and cytoskeleton redistribution was demonstrated in VIP + H2O2-treated cells. The knockdown of ZO-1 or the overexpression of caspase-3 blocked the effect of VIP on the cytoskeleton. Conclusion This study provides insights into the role of VIP in stabilizing the interaction between the actin cytoskeleton and cell junctions and may provide a promising targeted strategy for glaucoma treatment.
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Vernazza S, Tirendi S, Bassi AM, Traverso CE, Saccà SC. Neuroinflammation in Primary Open-Angle Glaucoma. J Clin Med 2020; 9:E3172. [PMID: 33007927 PMCID: PMC7601106 DOI: 10.3390/jcm9103172] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.
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Affiliation(s)
| | - Sara Tirendi
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Italy
| | - Anna Maria Bassi
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Italy
| | - Carlo Enrico Traverso
- Clinica Oculistica, DiNOGMI, University of Genoa, 16132 Genoa, Italy;
- Ophthalmology Unit, IRCCS-Polyclinic San Martino Hospital, 16132 Genoa, Italy;
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Wettschureck N, Strilic B, Offermanns S. Passing the Vascular Barrier: Endothelial Signaling Processes Controlling Extravasation. Physiol Rev 2019; 99:1467-1525. [PMID: 31140373 DOI: 10.1152/physrev.00037.2018] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A central function of the vascular endothelium is to serve as a barrier between the blood and the surrounding tissue of the body. At the same time, solutes and cells have to pass the endothelium to leave or to enter the bloodstream to maintain homeostasis. Under pathological conditions, for example, inflammation, permeability for fluid and cells is largely increased in the affected area, thereby facilitating host defense. To appropriately function as a regulated permeability filter, the endothelium uses various mechanisms to allow solutes and cells to pass the endothelial layer. These include transcellular and paracellular pathways of which the latter requires remodeling of intercellular junctions for its regulation. This review provides an overview on endothelial barrier regulation and focuses on the endothelial signaling mechanisms controlling the opening and closing of paracellular pathways for solutes and cells such as leukocytes and metastasizing tumor cells.
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Affiliation(s)
- Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research , Bad Nauheim , Germany ; and Centre for Molecular Medicine, Medical Faculty, J.W. Goethe University Frankfurt , Frankfurt , Germany
| | - Boris Strilic
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research , Bad Nauheim , Germany ; and Centre for Molecular Medicine, Medical Faculty, J.W. Goethe University Frankfurt , Frankfurt , Germany
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research , Bad Nauheim , Germany ; and Centre for Molecular Medicine, Medical Faculty, J.W. Goethe University Frankfurt , Frankfurt , Germany
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Stiff Substrates Enhance Endothelial Oxidative Stress in Response to Protein Kinase C Activation. Appl Bionics Biomech 2019; 2019:6578492. [PMID: 31110559 PMCID: PMC6487160 DOI: 10.1155/2019/6578492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/28/2019] [Accepted: 02/19/2019] [Indexed: 02/07/2023] Open
Abstract
Arterial stiffness, which increases with aging and hypertension, is an independent cardiovascular risk factor. While stiffer substrates are known to affect single endothelial cell morphology and migration, the effect of substrate stiffness on endothelial monolayer function is less understood. The objective of this study was to determine if substrate stiffness increased endothelial monolayer reactive oxygen species (ROS) in response to protein kinase C (PKC) activation and if this oxidative stress then impacted adherens junction integrity. Porcine aortic endothelial cells were cultured on varied stiffness polyacrylamide gels and treated with phorbol 12-myristate 13-acetate (PMA), which stimulates PKC and ROS without increasing actinomyosin contractility. PMA-treated endothelial cells on stiffer substrates increased ROS and adherens junction loss without increased contractility. ROS scavengers abrogated PMA effects on cell-cell junctions, with a more profound effect in cells on stiffer substrates. Finally, endothelial cells in aortae from elastin haploinsufficient mice (Eln+/-), which were stiffer than aortae from wild-type mice, showed decreased VE-cadherin colocalization with peripheral actin following PMA treatment. These data suggest that oxidative stress may be enhanced in endothelial cells in stiffer vessels, which could contribute to the association between arterial stiffness and cardiovascular disease.
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Alevriadou BR, Shanmughapriya S, Patel A, Stathopulos PB, Madesh M. Mitochondrial Ca 2+ transport in the endothelium: regulation by ions, redox signalling and mechanical forces. J R Soc Interface 2017; 14:rsif.2017.0672. [PMID: 29237825 DOI: 10.1098/rsif.2017.0672] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/16/2017] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca2+) transport by mitochondria is an important component of the cell Ca2+ homeostasis machinery in metazoans. Ca2+ uptake by mitochondria is a major determinant of bioenergetics and cell fate. Mitochondrial Ca2+ uptake occurs via the mitochondrial Ca2+ uniporter (MCU) complex, an inner mitochondrial membrane protein assembly consisting of the MCU Ca2+ channel, as its core component, and the MCU complex regulatory/auxiliary proteins. In this review, we summarize the current knowledge on the molecular nature of the MCU complex and its regulation by intra- and extramitochondrial levels of divalent ions and reactive oxygen species (ROS). Intracellular Ca2+ concentration ([Ca2+]i), mitochondrial Ca2+ concentration ([Ca2+]m) and mitochondrial ROS (mROS) are intricately coupled in regulating MCU activity. Here, we highlight the contribution of MCU activity to vascular endothelial cell (EC) function. Besides the ionic and oxidant regulation, ECs are continuously exposed to haemodynamic forces (either pulsatile or oscillatory fluid mechanical shear stresses, depending on the precise EC location within the arteries). Thus, we also propose an EC mechanotransduction-mediated regulation of MCU activity in the context of vascular physiology and atherosclerotic vascular disease.
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Affiliation(s)
- B Rita Alevriadou
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA .,Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA.,Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry, Temple University, Philadelphia, PA 19140, USA.,Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Akshar Patel
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.,Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA.,Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada N6A 5C1
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry, Temple University, Philadelphia, PA 19140, USA .,Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
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Zhou MS, Adam A, Raij L. Review: Interaction among angiotensin II, nitric oxide and oxidative stress. J Renin Angiotensin Aldosterone Syst 2016; 2:S59-S63. [DOI: 10.1177/14703203010020011001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Ming-Sheng Zhou
- Nephrology and Hypertension Section, Department of Veterans
Affairs Medical Center, and University of Minnesota, Minneapolis, Minnesota,
USA
| | - Ahmed Adam
- Nephrology and Hypertension Section, Department of Veterans
Affairs Medical Center, and University of Minnesota, Minneapolis, Minnesota,
USA
| | - Leopoldo Raij
- Nephrology and Hypertension Section, Department of Veterans
Affairs Medical Center, and University of Minnesota, Minneapolis, Minnesota,
USA,
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Heo KS, Berk BC, Abe JI. Disturbed Flow-Induced Endothelial Proatherogenic Signaling Via Regulating Post-Translational Modifications and Epigenetic Events. Antioxid Redox Signal 2016; 25:435-50. [PMID: 26714841 PMCID: PMC5076483 DOI: 10.1089/ars.2015.6556] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/02/2015] [Accepted: 12/23/2015] [Indexed: 12/21/2022]
Abstract
SIGNIFICANCE Hemodynamic shear stress, the frictional force exerted onto the vascular endothelial cell (EC) surface, influences vascular EC functions. Atherosclerotic plaque formation in the endothelium is known to be site specific: disturbed blood flow (d-flow) formed at the lesser curvature of the aortic arch and branch points promotes plaque formation, and steady laminar flow (s-flow) at the greater curvature is atheroprotective. RECENT ADVANCES Post-translational modifications (PTMs), including phosphorylation and SUMOylation, and epigenetic events, including DNA methylation and histone modifications, provide a new perspective on the pathogenesis of atherosclerosis, elucidating how gene expression is altered by d-flow. Activation of PKCζ and p90RSK, SUMOylation of ERK5 and p53, and DNA hypermethylation are uniquely induced by d-flow, but not by s-flow. CRITICAL ISSUES Extensive cross talk has been observed among the phosphorylation, SUMOylation, acetylation, and methylation PTMs, as well as among epigenetic events along the cascade of d-flow-induced signaling, from the top (mechanosensory systems) to the bottom (epigenetic events). In addition, PKCζ activation plays a role in regulating SUMOylation-related enzymes of PIAS4, p90RSK activation plays a role in regulating SUMOylation-related enzymes of Sentrin/SUMO-specific protease (SENP)2, and DNA methyltransferase SUMOylation may play a role in d-flow signaling. FUTURE DIRECTIONS Although possible contributions of DNA events such as histone modification and the epigenetic and cytosolic events of PTMs in d-flow signaling have become clearer, determining the interplay of each PTM and epigenetic event will provide a new paradigm to elucidate the difference between d-flow and s-flow and lead to novel therapeutic interventions to inhibit plaque formation. Antioxid. Redox Signal. 25, 435-450.
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Affiliation(s)
- Kyung-Sun Heo
- Department of Cardiology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Bradford C. Berk
- Department of Medicine, Aab Cardiovascular Research Institute, University of Rochester Medical Center, Rochester, New York
| | - Jun-ichi Abe
- Department of Cardiology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Yurdagul A, Orr AW. Blood Brothers: Hemodynamics and Cell-Matrix Interactions in Endothelial Function. Antioxid Redox Signal 2016; 25:415-34. [PMID: 26715135 PMCID: PMC5011636 DOI: 10.1089/ars.2015.6525] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/25/2015] [Accepted: 12/23/2015] [Indexed: 12/29/2022]
Abstract
SIGNIFICANCE Alterations in endothelial function contribute to a variety of vascular diseases. In pathological conditions, the endothelium shows a reduced ability to regulate vasodilation (endothelial dysfunction) and a conversion toward a proinflammatory and leaky phenotype (endothelial activation). At the interface between the vessel wall and blood, the endothelium exists in a complex microenvironment and must translate changes in these environmental signals to alterations in vessel function. Mechanical stimulation and endothelial cell interactions with the vascular matrix, as well as a host of soluble factors, coordinately contribute to this dynamic regulation. RECENT ADVANCES Blood hemodynamics play an established role in the regulation of endothelial function. However, a growing body of work suggests that subendothelial matrix composition similarly and coordinately regulates endothelial cell phenotype such that blood flow affects matrix remodeling, which affects the endothelial response to flow. CRITICAL ISSUES Hemodynamics and soluble factors likely affect endothelial matrix remodeling through multiple mechanisms, including transforming growth factor β signaling and alterations in cell-matrix receptors, such as the integrins. Likewise, differential integrin signaling following matrix remodeling appears to regulate several key flow-induced responses, including nitric oxide production, regulation of oxidant stress, and activation of proinflammatory signaling and gene expression. Microvascular remodeling responses, such as angiogenesis and arteriogenesis, may also show coordinated regulation by flow and matrix. FUTURE DIRECTIONS Identifying the mechanisms regulating the dynamic interplay between hemodynamics and matrix remodeling and their contribution to the pathogenesis of cardiovascular disease remains an important research area with therapeutic implications across a variety of conditions. Antioxid. Redox Signal. 25, 415-434.
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Affiliation(s)
- Arif Yurdagul
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center–Shreveport, Shreveport, Louisiana
| | - A. Wayne Orr
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center–Shreveport, Shreveport, Louisiana
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center–Shreveport, Shreveport, Louisiana
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Yang G, Qian C, Wang N, Lin C, Wang Y, Wang G, Piao X. Tetramethylpyrazine Protects Against Oxygen-Glucose Deprivation-Induced Brain Microvascular Endothelial Cells Injury via Rho/Rho-kinase Signaling Pathway. Cell Mol Neurobiol 2016; 37:619-633. [DOI: 10.1007/s10571-016-0398-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/22/2016] [Indexed: 01/24/2023]
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Abstract
Despite extensive study of the EGF receptor (EGFR) signaling network, the immediate posttranslational changes that occur in response to growth factor stimulation remain poorly characterized; as a result, the biological mechanisms underlying signaling initiation remain obscured. To address this deficiency, we have used a mass spectrometry-based approach to measure system-wide phosphorylation changes throughout the network with 10-s resolution in the 80 s after stimulation in response to a range of eight growth factor concentrations. Significant changes were observed on proteins far downstream in the network as early as 10 s after stimulation, indicating a system capable of transmitting information quickly. Meanwhile, canonical members of the EGFR signaling network fall into clusters with distinct activation patterns. Src homology 2 domain containing transforming protein (Shc) and phosphoinositol 3-kinase (PI3K) phosphorylation levels increase rapidly, but equilibrate within 20 s, whereas proteins such as Grb2-associated binder-1 (Gab1) and SH2-containing tyrosine phosphatase (SHP2) show slower, sustained increases. Proximity ligation assays reveal that Shc and Gab1 phosphorylation patterns are representative of separate timescales for physical association with the receptor. Inhibition of phosphatases with vanadate reveals site-specific regulatory mechanisms and also uncovers primed activating components in the network, including Src family kinases, whose inhibition affects only a subset of proteins within the network. The results presented highlight the complexity of signaling initiation and provide a window into exploring mechanistic hypotheses about receptor tyrosine kinase (RTK) biology.
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Scheitlin CG, Julian JA, Shanmughapriya S, Madesh M, Tsoukias NM, Alevriadou BR. Endothelial mitochondria regulate the intracellular Ca2+ response to fluid shear stress. Am J Physiol Cell Physiol 2016; 310:C479-90. [PMID: 26739489 DOI: 10.1152/ajpcell.00171.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/04/2016] [Indexed: 02/04/2023]
Abstract
Shear stress is known to stimulate an intracellular free calcium concentration ([Ca(2+)]i) response in vascular endothelial cells (ECs). [Ca(2+)]i is a key second messenger for signaling that leads to vasodilation and EC survival. Although it is accepted that the shear-induced [Ca(2+)]i response is, in part, due to Ca(2+) release from the endoplasmic reticulum (ER), the role of mitochondria (second largest Ca(2+) store) is unknown. We hypothesized that the mitochondria play a role in regulating [Ca(2+)]i in sheared ECs. Cultured ECs, loaded with a Ca(2+)-sensitive fluorophore, were exposed to physiological levels of shear stress. Shear stress elicited [Ca(2+)]i transients in a percentage of cells with a fraction of them displaying oscillations. Peak magnitudes, percentage of oscillating ECs, and oscillation frequencies depended on the shear level. [Ca(2+)]i transients/oscillations were present when experiments were conducted in Ca(2+)-free solution (plus lanthanum) but absent when ECs were treated with a phospholipase C inhibitor, suggesting that the ER inositol 1,4,5-trisphosphate receptor is responsible for the [Ca(2+)]i response. Either a mitochondrial uncoupler or an electron transport chain inhibitor, but not a mitochondrial ATP synthase inhibitor, prevented the occurrence of transients and especially inhibited the oscillations. Knockdown of the mitochondrial Ca(2+) uniporter also inhibited the shear-induced [Ca(2+)]i transients/oscillations compared with controls. Hence, EC mitochondria, through Ca(2+) uptake/release, regulate the temporal profile of shear-induced ER Ca(2+) release. [Ca(2+)]i oscillation frequencies detected were within the range for activation of mechanoresponsive kinases and transcription factors, suggesting that dysfunctional EC mitochondria may contribute to cardiovascular disease by deregulating the shear-induced [Ca(2+)]i response.
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Affiliation(s)
- Christopher G Scheitlin
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Justin A Julian
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - B Rita Alevriadou
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio;
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Affiliation(s)
- Anping Cai
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
| | - Yingling Zhou
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
| | - Liwen Li
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
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Marinković G, Heemskerk N, van Buul JD, de Waard V. The Ins and Outs of Small GTPase Rac1 in the Vasculature. J Pharmacol Exp Ther 2015; 354:91-102. [PMID: 26036474 DOI: 10.1124/jpet.115.223610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/01/2015] [Indexed: 12/16/2022] Open
Abstract
The Rho family of small GTPases forms a 20-member family within the Ras superfamily of GTP-dependent enzymes that are activated by a variety of extracellular signals. The most well known Rho family members are RhoA (Ras homolog gene family, member A), Cdc42 (cell division control protein 42), and Rac1 (Ras-related C3 botulinum toxin substrate 1), which affect intracellular signaling pathways that regulate a plethora of critical cellular functions, such as oxidative stress, cellular contacts, migration, and proliferation. In this review, we describe the current knowledge on the role of GTPase Rac1 in the vasculature. Whereas most recent reviews focus on the role of vascular Rac1 in endothelial cells, in the present review we also highlight the functional involvement of Rac1 in other vascular cells types, namely, smooth muscle cells present in the media and fibroblasts located in the adventitia of the vessel wall. Collectively, this overview shows that Rac1 activity is involved in various functions within one cell type at distinct locations within the cell, and that there are overlapping but also cell type-specific functions in the vasculature. Chronically enhanced Rac1 activity seems to contribute to vascular pathology; however, Rac1 is essential to vascular homeostasis, which makes Rac1 inhibition as a therapeutic option a delicate balancing act.
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Affiliation(s)
- Goran Marinković
- Department Medical Biochemistry (G.M., V.d.W.) and Department of Molecular Cell Biology (N.H., J.D.v.B.), Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Niels Heemskerk
- Department Medical Biochemistry (G.M., V.d.W.) and Department of Molecular Cell Biology (N.H., J.D.v.B.), Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jaap D van Buul
- Department Medical Biochemistry (G.M., V.d.W.) and Department of Molecular Cell Biology (N.H., J.D.v.B.), Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Vivian de Waard
- Department Medical Biochemistry (G.M., V.d.W.) and Department of Molecular Cell Biology (N.H., J.D.v.B.), Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Chatterjee S, Nieman GF, Christie JD, Fisher AB. Shear stress-related mechanosignaling with lung ischemia: lessons from basic research can inform lung transplantation. Am J Physiol Lung Cell Mol Physiol 2014; 307:L668-80. [PMID: 25239915 DOI: 10.1152/ajplung.00198.2014] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cessation of blood flow represents a physical event that is sensed by the pulmonary endothelium leading to a signaling cascade that has been termed "mechanotransduction." This paradigm has clinical relevance for conditions such as pulmonary embolism, lung bypass surgery, and organ procurement and storage during lung transplantation. On the basis of our findings with stop of flow, we postulate that normal blood flow is "sensed" by the endothelium by virtue of its location at the interface of the blood and vessel wall and that this signal is necessary to maintain the endothelial cell membrane potential. Stop of flow is sensed by a "mechanosome" consisting of PECAM-VEGF receptor-VE cadherin that is located in the endothelial cell caveolae. Activation of the mechanosome results in endothelial cell membrane depolarization that in turn leads to activation of NADPH oxidase (NOX2) to generate reactive oxygen species (ROS). Endothelial depolarization additionally results in opening of T-type voltage-gated Ca(2+) channels, increased intracellular Ca(2+), and activation of nitric oxide (NO) synthase with resultant generation of NO. Increased NO causes vasodilatation whereas ROS provide a signal for neovascularization; however, with lung transplantation overproduction of ROS and NO can cause oxidative injury and/or activation of proteins that drive inflammation and cell death. Understanding the key events in the mechanosignaling cascade has important lessons for the design of strategies or interventions that may reduce injury during storage of donor lungs with the goal to increase the availability of lungs suitable for donation and thus improving access to lung transplantation.
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Affiliation(s)
- Shampa Chatterjee
- Institute for Environmental Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennyslvania;
| | - Gary F Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York; and
| | - Jason D Christie
- Pulmonary Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Aron B Fisher
- Institute for Environmental Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennyslvania
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16
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Abstract
Endothelial cell dysfunction is the hallmark of every cardiovascular disease/condition, including atherosclerosis and ischemia/reperfusion injury. Fluid shear stress acting on the vascular endothelium is known to regulate cell homeostasis. Altered hemodynamics is thought to play a causative role in endothelial dysfunction. The dysfunction is associated with/preceded by mitochondrial oxidative stress. Studies by our group and others have shown that the form and/or function of the mitochondrial network are affected when endothelial cells are exposed to shear stress in the absence or presence of additional physicochemical stimuli. The present review will summarize the current knowledge on the interconnections among intracellular Ca2+ - nitric oxide - mitochondrial reactive oxygen species, mitochondrial fusion/fission, autophagy/mitophagy, and cell apoptosis vs. survival. More specifically, it will list the evidence on potential regulation of the above intracellular species and processes by the fluid shear stress acting on the endothelium under either physiological flow conditions or during reperfusion (following a period of ischemia). Understanding how the local hemodynamics affects mitochondrial physiology and the cell redox state may lead to development of novel therapeutic strategies for prevention or treatment of the endothelial dysfunction and, hence, of cardiovascular disease.
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17
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Abstract
Mechanical forces influence many biological processes via activation of signaling molecules, including the family of Rho GTPases. Within the endothelium, the mechanical force of fluid shear stress regulates the spatiotemporal activation of Rho GTPases, including Rac1. Shear stress-induced Rac1 activation is required for numerous essential biological processes, including changes in permeability, alignment of the actin cytoskeleton, redox signaling, and changes in gene expression. Thus, identifying mechanisms of Rac1 activation and the spatial cues that direct proper localization of the GTPase is essential in order to gain a comprehensive understanding the role of Rac1 in shear stress responses. This commentary will highlight our current understanding of how Rac1 activity is regulated in response to shear stress, as well as the downstream consequences of Rac1 activation.
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Affiliation(s)
- Caitlin Collins
- Department of Cell Biology and Physiology; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
| | - Ellie Tzima
- Department of Cell Biology and Physiology; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
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Mittal M, Siddiqui MR, Tran K, Reddy SP, Malik AB. Reactive oxygen species in inflammation and tissue injury. Antioxid Redox Signal 2014; 20:1126-67. [PMID: 23991888 PMCID: PMC3929010 DOI: 10.1089/ars.2012.5149] [Citation(s) in RCA: 2714] [Impact Index Per Article: 271.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract Reactive oxygen species (ROS) are key signaling molecules that play an important role in the progression of inflammatory disorders. An enhanced ROS generation by polymorphonuclear neutrophils (PMNs) at the site of inflammation causes endothelial dysfunction and tissue injury. The vascular endothelium plays an important role in passage of macromolecules and inflammatory cells from the blood to tissue. Under the inflammatory conditions, oxidative stress produced by PMNs leads to the opening of inter-endothelial junctions and promotes the migration of inflammatory cells across the endothelial barrier. The migrated inflammatory cells not only help in the clearance of pathogens and foreign particles but also lead to tissue injury. The current review compiles the past and current research in the area of inflammation with particular emphasis on oxidative stress-mediated signaling mechanisms that are involved in inflammation and tissue injury.
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Affiliation(s)
- Manish Mittal
- 1 Department of Pharmacology, Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, Illinois
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19
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Chatterjee S, Fisher AB. Mechanotransduction in the endothelium: role of membrane proteins and reactive oxygen species in sensing, transduction, and transmission of the signal with altered blood flow. Antioxid Redox Signal 2014; 20:899-913. [PMID: 24328670 PMCID: PMC3924805 DOI: 10.1089/ars.2013.5624] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
SIGNIFICANCE Changes in shear stress associated with alterations in blood flow initiate a signaling cascade that modulates the vascular phenotype. Shear stress is "sensed" by the endothelium via a mechanosensitive complex on the endothelial cell (EC) membrane that has been characterized as a "mechanosome" consisting of caveolae, platelet endothelial cell adhesion molecule (PECAM), vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial (VE)-cadherin, and possibly other elements. This shear signal is transduced by cell membrane ion channels and various kinases and results in the activation of NADPH oxidase (type 2) with the production of reactive oxygen species (ROS). RECENT ADVANCES The signaling cascade associated with stop of shear, as would occur in vivo with various obstructive pathologies, leads to cell proliferation and eventual revascularization. CRITICAL ISSUES AND FUTURE DIRECTIONS Although several elements of mechanosensing such as the sensing event, the transduction, transmission, and reception of the mechanosignal are now reasonably well understood, the links among these discrete steps in the pathway are not clear. Thus, identifying the mechanisms for the interaction of the K(ATP) channel, the kinases, and ROS to drive long-term adaptive responses in ECs is necessary. A critical re-examination of the signaling events associated with complex flow patterns (turbulent, oscillatory) under physiological conditions is also essential for the progress in the field. Since these complex shear patterns may be associated with an atherosclerosis susceptible phenotype, a specific challenge will be the pharmacological modulation of the responses to altered signaling events that occur at specific sites of disturbed or obstructed flow.
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Affiliation(s)
- Shampa Chatterjee
- Institute for Environmental Medicine, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
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20
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Abstract
Redox agents have been historically considered pathological agents which can react with and damage many biological macromolecules including DNA, proteins, and lipids. However, a growing number of reports have suggested that mammalian cells can rapidly respond to ligand stimulation with a change in intracellular ROS thus indicating that the production of intracellular redox agents is tightly regulated and that they serve as intracellular signaling molecules being involved in a variety of cell signaling pathways. Numerous observations have suggested that some members of the Ras GTPase superfamily appear to regulate the production of redox agents and that oxidants can function as effector molecules for the small GTPases, thus contributing to their overall biological function. In addition, many of the Ras superfamily small GTPases have been shown to be redox sensitive, thanks to the presence of redox-sensitive sequences in their primary structure. The action of redox agents on these redox-sensitive GTPases is similar to that of guanine nucleotide exchange factors in that they perturb GTPase nucleotide-binding interactions that result in the enhancement of the guanine nucleotide exchange of small GTPases. Thus, Ras GTPases may act both as upstream regulators and downstream effectors of redox agents. Here we overview current understanding concerning the interplay between Ras GTPases and redox agents, also taking into account pathological implications of misregulation of this cross talk and highlighting the potentiality of these cellular pathways as new therapeutical targets for different pathologies.
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21
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Liu Y, Collins C, Kiosses WB, Murray AM, Joshi M, Shepherd TR, Fuentes EJ, Tzima E. A novel pathway spatiotemporally activates Rac1 and redox signaling in response to fluid shear stress. ACTA ACUST UNITED AC 2013; 201:863-73. [PMID: 23733346 PMCID: PMC3678169 DOI: 10.1083/jcb.201207115] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The GEF Tiam1 acts as a novel molecular link to the VE-cadherin–p67phox–Par3 polarity complex, leading to localized activation of Rac1 and NADPH oxidase in response to fluid flow. Hemodynamic forces regulate embryonic organ development, hematopoiesis, vascular remodeling, and atherogenesis. The mechanosensory stimulus of blood flow initiates a complex network of intracellular pathways, including activation of Rac1 GTPase, establishment of endothelial cell (EC) polarity, and redox signaling. The activity of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase can be modulated by the GTP/GDP state of Rac1; however, the molecular mechanisms of Rac1 activation by flow are poorly understood. Here, we identify a novel polarity complex that directs localized Rac1 activation required for downstream reactive oxygen species (ROS) production. Vav2 is required for Rac1 GTP loading, whereas, surprisingly, Tiam1 functions as an adaptor in a VE-cadherin–p67phox–Par3 polarity complex that directs localized activation of Rac1. Furthermore, loss of Tiam1 led to the disruption of redox signaling both in vitro and in vivo. Our results describe a novel molecular cascade that regulates redox signaling by the coordinated regulation of Rac1 and by linking components of the polarity complex to the NADPH oxidase.
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Affiliation(s)
- Yunhao Liu
- Department of Cell Biology and Physiology, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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22
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Coso S, Harrison I, Harrison CB, Vinh A, Sobey CG, Drummond GR, Williams ED, Selemidis S. NADPH oxidases as regulators of tumor angiogenesis: current and emerging concepts. Antioxid Redox Signal 2012; 16:1229-47. [PMID: 22229841 DOI: 10.1089/ars.2011.4489] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and peroxynitrite are generated ubiquitously by all mammalian cells and have been understood for many decades as inflicting cell damage and as causing cancer by oxidation and nitration of macromolecules, including DNA, RNA, proteins, and lipids. RECENT ADVANCES A current concept suggests that ROS can also promote cell signaling pathways triggered by growth factors and transcription factors that ultimately regulate cell proliferation, differentiation, and apoptosis, all of which are important hallmarks of tumor cell proliferation and angiogenesis. Moreover, an emerging concept indicates that ROS regulate the functions of immune cells that infiltrate the tumor environment and stimulate angiogenesis, such as macrophages and specific regulatory T cells. CRITICAL ISSUES In this article, we highlight that the NADPH oxidase family of ROS-generating enzymes are the key sources of ROS and, thus, play an important role in redox signaling within tumor, endothelial, and immune cells thereby promoting tumor angiogenesis. FUTURE DIRECTIONS Knowledge of these intricate ROS signaling pathways and identification of the culprit NADPH oxidases is likely to reveal novel therapeutic opportunities to prevent angiogenesis that occurs during cancer and which is responsible for the revascularization after current antiangiogenic treatment.
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Affiliation(s)
- Sanja Coso
- Centre for Cancer Research, Monash Institute of Medical Research, Monash University, Victoria, Australia
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23
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Molecular Crosstalk between Integrins and Cadherins: Do Reactive Oxygen Species Set the Talk? JOURNAL OF SIGNAL TRANSDUCTION 2011; 2012:807682. [PMID: 22203898 PMCID: PMC3238397 DOI: 10.1155/2012/807682] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 08/24/2011] [Indexed: 11/18/2022]
Abstract
The coordinate modulation of the cellular functions of cadherins and integrins plays an essential role in fundamental physiological and pathological processes, including morphogenesis, tissue differentiation and renewal, wound healing, immune surveillance, inflammatory response, tumor progression, and metastasis. However, the molecular mechanisms underlying the fine-tuned functional communication between cadherins and integrins are still elusive. This paper focuses on recent findings towards the involvement of reactive oxygen species (ROS) in the regulation of cell adhesion and signal transduction functions of integrins and cadherins, pointing to ROS as emerging strong candidates for modulating the molecular crosstalk between cell-matrix and cell-cell adhesion receptors.
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24
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The Interplay between ROS and Ras GTPases: Physiological and Pathological Implications. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2012:365769. [PMID: 22175014 PMCID: PMC3235814 DOI: 10.1155/2012/365769] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 10/18/2011] [Indexed: 01/23/2023]
Abstract
The members of the RasGTPase superfamily are involved in various signaling networks responsible for fundamental cellular processes. Their activity is determined by their guanine nucleotide-bound state. Recent evidence indicates that some of these proteins may be regulated by redox agents. Reactive oxygen species (ROSs) and reactive nitrogen species (RNSs) have been historically considered pathological agents which can react with and damage many biological macromolecules including DNA, proteins, and lipids. However, a growing number of reports have suggested that the intracellular production of ROS is tightly regulated and that these redox agents serve as signaling molecules being involved in a variety of cell signaling pathways. Numerous observations have suggested that some Ras GTPases appear to regulate ROS production and that oxidants function as effector molecules for the small GTPases, thus contributing to their overall biological function. Thus, redox agents may act both as upstream regulators and as downstream effectors of Ras GTPases. Here we discuss current understanding concerning mechanisms and physiopathological implications of the interplay between GTPases and redox agents.
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25
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Heo KS, Fujiwara K, Abe JI. Disturbed-flow-mediated vascular reactive oxygen species induce endothelial dysfunction. Circ J 2011; 75:2722-30. [PMID: 22076424 DOI: 10.1253/circj.cj-11-1124] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Emerging evidence is revealing the different roles of steady laminar flow (s-flow) and disturbed flow (d-flow) in the regulation of the vascular endothelium. s-flow is atheroprotective while d-flow creates an atheroprone environment. Most recently, we found unique atheroprone signals, which involve protein kinase C (PKC)ζ activation, elicited by d-flow. We and others have defined a novel role for PKCζ as a shared mediator for tumor necrosis factor alpha (TNF alpha) and d-flow, which cause pro-inflammatory and pro-apoptotic events in endothelial cells (ECs) in the atheroprone environment. Under such conditions, ONOO(-) formation is increased in a d-flow-mediated PKCζ-dependent manner. Here, we propose a new signaling pathway involving d-flow-induced EC inflammation via PKCζ-ERK5 interaction-mediated downregulation of KLF2/eNOS stability, which leads to PKCζ-mediated p53-SUMOylation and EC apoptosis. In addition, we highlight several mechanisms contributing to endothelial dysfunction, focusing on the relations between flow patterns and activation of reactive oxygen species generating enzymes.
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Affiliation(s)
- Kyung-Sun Heo
- Aab Cardiovascular Research Institute, University of Rochester, NY, USA
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26
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Ning ZY, An YF, Qi WB, Wang H, Pan JQ, Wu XT, Liao M. Na+/H+ exchanger 1 gene expression in tissues of yellow chicken. Biochem Genet 2011; 50:227-34. [PMID: 21952874 DOI: 10.1007/s10528-011-9464-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 04/28/2011] [Indexed: 10/17/2022]
Abstract
The Na(+)/H(+) exchanger 1 (NHE1) transmembrane protein regulates intracellular pH, cell survival, cell growth, cell differentiation and plays a critical role in the progression of some diseases, including the pathogenesis of J avian leukosis. The chicken is an ideal model to study the function of NHE1 because it has developed highly efficient Na(+)-absorptive mechanisms in its small and large intestines. To date, there has been no detailed expression analysis to determine NHE1 expression in various tissues of the chicken. We determined the mRNA and protein expression levels of avian NHE1 by real-time quantitative PCR and immunohistochemical analysis. NHE1 mRNA was detected in all chicken tissues examined. Protein expression levels varied widely among tissues and did not always correlate with mRNA expression. Determining the mRNA and protein of NHE1 expression patterns in chicken should help to delineate the NHE1 role in different tissues and its contribution to physiological and pathological processes. These data provide the basis for examining the distinct function of chicken NHE1 compared with its mammalian counterpart.
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Affiliation(s)
- Zhang-yong Ning
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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27
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Takabe W, Warabi E, Noguchi N. Anti-atherogenic effect of laminar shear stress via Nrf2 activation. Antioxid Redox Signal 2011; 15:1415-26. [PMID: 21126170 DOI: 10.1089/ars.2010.3433] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fluid shear stress plays a critical role in the regulation of vascular biology and its pathology, such as atherosclerosis, via modulation of redox balance. Both pro-atherogenic (either oscillatory or turbulent, nonunidirectional) shear stress and anti-atherogenic (either steady or pulsatile, unidirectional laminar) shear stress stimulate production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are involved in signal transduction of gene expression. Nonunidirectional shear stress induces pro-atherogenic genes encoding adhesion molecules and chemokines in a manner dependent on production of both superoxide and nitric oxide. Steady or pulsatile laminar shear stress induces expression of genes encoding cytoprotective enzymes for glutathione biosynthesis and detoxification, which are regulated by the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2). We show that pulsatile laminar shear stress (PLSS)-induced expression of adhesion molecules and chemokines was enhanced in human umbilical vein endothelial cells (HUVEC) treated with Nrf2 siRNA and arterial endothelial cells isolated from Nrf2 knockout mice. Hence, we propose the hypothesis that PLSS maintains the endothelium in an anti-atherogenic state via intracellular antioxidant levels increased as a result of Nrf2 activation, thereby preventing excess ROS/RNS production required for pro-atherogenic gene expression.
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Affiliation(s)
- Wakako Takabe
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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28
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Selective Rac1 inhibition protects renal tubular epithelial cells from oxalate-induced NADPH oxidase-mediated oxidative cell injury. ACTA ACUST UNITED AC 2011; 40:415-23. [PMID: 21814770 DOI: 10.1007/s00240-011-0405-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
Abstract
Oxalate-induced oxidative cell injury is one of the major mechanisms implicated in calcium oxalate nucleation, aggregation and growth of kidney stones. We previously demonstrated that oxalate-induced NADPH oxidase-derived free radicals play a significant role in renal injury. Since NADPH oxidase activation requires several regulatory proteins, the primary goal of this study was to characterize the role of Rac GTPase in oxalate-induced NADPH oxidase-mediated oxidative injury in renal epithelial cells. Our results show that oxalate significantly increased membrane translocation of Rac1 and NADPH oxidase activity of renal epithelial cells in a time-dependent manner. We found that NSC23766, a selective inhibitor of Rac1, blocked oxalate-induced membrane translocation of Rac1 and NADPH oxidase activity. In the absence of Rac1 inhibitor, oxalate exposure significantly increased hydrogen peroxide formation and LDH release in renal epithelial cells. In contrast, Rac1 inhibitor pretreatment, significantly decreased oxalate-induced hydrogen peroxide production and LDH release. Furthermore, PKC α and δ inhibitor, oxalate exposure did not increase Rac1 protein translocation, suggesting that PKC resides upstream from Rac1 in the pathway that regulates NADPH oxidase. In conclusion, our data demonstrate for the first time that Rac1-dependent activation of NADPH oxidase might be a crucial mechanism responsible for oxalate-induced oxidative renal cell injury. These findings suggest that Rac1 signaling plays a key role in oxalate-induced renal injury, and may serve as a potential therapeutic target to prevent calcium oxalate crystal deposition in stone formers and reduce recurrence.
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29
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Abstract
The physiological mechanisms that regulate adaptive plasticity of clonal organisms are key to their success in changing environments. Here, we review the mechanisms that regulate morphological plasticity of colonial hydrozoans. There is a heritable, genetic basis to colony form, but environmentally-induced plasticity and self-reinforcing developmental physiology explain much of total phenotypic variance. Morphological development of colonial hydrozoans emerges from interactions among (1) behaviors which drive gastrovascular transport, (2) architecture of the gastrovascular system that determines hydrodynamic characteristics of vascular flow, and, (3) gene products that vary in response to physiological signals provided by gastrovascular transport. Several morphogenetic signaling mechanisms have been identified, including, reactive oxygen species and nutrient concentrations in the hydroplasm, and hydromechanical forces associated with gastrovascular transport. We present a conceptual model of the interacting forces that drive hydrozoan morphological development. Several avenues for future research are suggested by the synthesis of information from prior studies of hydrozoans. Elucidating the morphogenetic signaling pathways responsive to metabolites or hydromechanical forces and the epigenetic effect of vascular architecture on colony form may give new insight into the self-maintenance of indeterminately growing and continuously developing vascular systems.
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Affiliation(s)
- S R Dudgeon
- Department of Biology, California State University, Northridge, CA, USA
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30
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Du J, Liu J, Smith BJ, Tsao MS, Cullen JJ. Role of Rac1-dependent NADPH oxidase in the growth of pancreatic cancer. Cancer Gene Ther 2010; 18:135-43. [PMID: 21037555 PMCID: PMC3058504 DOI: 10.1038/cgt.2010.64] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
K-ras mutations occur in as high as 95% of patients with pancreatic cancer. K-ras activates Rac1-dependent NADPH oxidase, a key source of superoxide. Superoxide plays an important role in pancreatic cancer cell proliferation and scavenging or decreasing the levels of superoxide inhibits pancreatic cancer cell growth both in vitro and in vivo. DNA microarray analysis and RT-PCR has demonstrated that Rac1 is also upregulated in pancreatic cancer. The aim of this study was to determine if inhibiting Rac1 would alter pancreatic tumor cell behavior. Human pancreatic cancer cells with mutant K-ras (MIA PaCa-2), wild-type K-ras (BxPC-3), and the immortal H6c7 cell line (pancreatic ductal epithelium) expressing K-ras oncogene (H6c7eR-KrasT) that is tumorigenic, were infected with a dominant/negative Rac1 construct (AdN17Rac1). In cells with mutant K-ras, AdN17Rac1 decreased rac activity, decreased superoxide levels, and inhibited in vitro growth. However in the BxPC-3 cell line, AdN17Rac1 did not change rac activity, superoxide levels, or in vitro cell growth. Additionally, AdN17Rac1 decreased superoxide levels and inhibited in vitro growth in the KrasT tumorigenic cell line, but had no effect in the immortalized H6c7 cell line. In human pancreatic tumor xenografts, intratumoral injections of AdN17Rac1 inhibited tumor growth. These results suggest that activation of Rac1-dependent superoxide generation leads to pancreatic cancer cell proliferation. In pancreatic cancer inhibition of Rac1 may be a potential therapeutic target.
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Affiliation(s)
- J Du
- Department of Radiation Oncology, University of Iowa College of Medicine, Iowa City, IA, USA
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31
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Increased oxidative stress in atherosclerosis-predisposed regions of the mouse aorta. Life Sci 2010; 87:100-10. [PMID: 20553954 DOI: 10.1016/j.lfs.2010.05.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 04/20/2010] [Accepted: 05/13/2010] [Indexed: 11/21/2022]
Abstract
AIMS The localization of atherosclerotic lesions to predictable regions in mammalian arteries has been recognized for over a century. We sought to investigate the association between oxidative stress and regional susceptibility of the mouse aorta to atherosclerosis. MAIN METHODS En face confocal microscopy was employed to assess oxidative stress in the aortic intima of atherosclerosis-susceptible and protected regions of wild-type C57BL/6 mouse. Expression of reactive oxygen species and antioxidant producing genes were compared in endothelial cells from the susceptible and protected regions. KEY FINDINGS In vivo administration of redox-sensitive fluorescent dyes revealed an increase in the production of reactive oxygen species (ROS) in the atherosclerosis-susceptible regions relative to the protected regions. In contrast, Hoechst a redox-insensitive dye distributed evenly in the susceptible and protected regions. Accumulation of superoxide in the susceptible regions of the aorta was significantly blocked by the administration of Diphenyleneiodonium, a flavoprotein inhibitor. mRNA levels of superoxide-producing and scavenging enzymes were significantly increased in the regions predisposed to atherosclerosis. The regional difference in oxidative stress was at a lesser magnitude in BALB/c than the atherosclerosis-susceptible mouse (C57BL/6). SIGNIFICANCE Our study for the first time demonstrated an augmented oxidative stress in atherosclerosis-susceptible regions of the normal mouse aorta.
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32
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Bai X, Wang X, Xu Q. Endothelial damage and stem cell repair in atherosclerosis. Vascul Pharmacol 2010; 52:224-9. [DOI: 10.1016/j.vph.2010.02.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/27/2010] [Accepted: 02/09/2010] [Indexed: 11/24/2022]
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33
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Funk SD, Yurdagul A, Green JM, Jhaveri KA, Schwartz MA, Orr AW. Matrix-specific protein kinase A signaling regulates p21-activated kinase activation by flow in endothelial cells. Circ Res 2010; 106:1394-403. [PMID: 20224042 DOI: 10.1161/circresaha.109.210286] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE Atherosclerosis is initiated by blood flow patterns that activate inflammatory pathways in endothelial cells. Activation of inflammatory signaling by fluid shear stress is highly dependent on the composition of the subendothelial extracellular matrix. The basement membrane proteins laminin and collagen found in normal vessels suppress flow-induced p21 activated kinase (PAK) and nuclear factor (NF)-kappaB activation. By contrast, the provisional matrix proteins fibronectin and fibrinogen found in wounded or inflamed vessels support flow-induced PAK and NF-kappaB activation. PAK mediates both flow-induced permeability and matrix-specific activation of NF-kappaB. OBJECTIVE To elucidate the mechanisms regulating matrix-specific PAK activation. METHODS AND RESULTS We now show that matrix composition does not affect the upstream pathway by which flow activates PAK (integrin activation, Rac). Instead, basement membrane proteins enhance flow-induced protein kinase (PK)A activation, which suppresses PAK. Inhibiting PKA restored flow-induced PAK and NF-kappaB activation in cells on basement membrane proteins, whereas stimulating PKA inhibited flow-induced activation of inflammatory signaling in cells on fibronectin. PKA suppressed inflammatory signaling through PAK inhibition. Activating PKA by injection of the prostacyclin analog iloprost reduced PAK activation and inflammatory gene expression at sites of disturbed flow in vivo, whereas inhibiting PKA by PKA inhibitor (PKI) injection enhanced PAK activation and inflammatory gene expression. Inhibiting PAK prevented the enhancement of inflammatory gene expression by PKI. CONCLUSIONS Basement membrane proteins inhibit inflammatory signaling in endothelial cells via PKA-dependent inhibition of PAK.
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Affiliation(s)
- Steven Daniel Funk
- Department Cell Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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34
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35
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DNA damage and repair in a model of rat vascular injury. Clin Sci (Lond) 2009; 118:473-85. [PMID: 19804370 DOI: 10.1042/cs20090416] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/18/2009] [Accepted: 10/05/2009] [Indexed: 12/21/2022]
Abstract
Restenosis rate following vascular interventions still limits their long-term success. Oxidative stress plays a relevant role in this pathophysiological phenomenon, but less attention has been devoted to its effects on DNA damage and to the subsequent mechanisms of repair. We analysed in a model of arteriotomy-induced stenosis in rat carotids the time-dependent expression of DNA damage markers and of DNA repair genes, together with the assessment of proliferation and apoptosis indexes. The expression of the oxidative DNA damage marker 7,8-dihydro-8-oxo-2'-deoxyguanosine was increased at 3 and 7 days after arteriotomy, with immunostaining distributed in the injured vascular wall and in perivascular tissue. The expression of the DNA damage marker phospho-H2A.X was less relevant but increasing from 4 hrs to 7 days after arteriotomy, with immunostaining prevalently present in the adventitia and, to a lesser extent, in medial smooth muscle cells at the injury site. RT-PCR indicated a decrease of 8 out of 12 genes of the DNA repair machinery we selected from 4 hrs to 7 days after arteriotomy with the exception of increased Muyth and Slk genes (p<0.05). Western Blot revealed a decrease of p53 and catalase at 3 days after arteriotomy (p<0.05). A maximal 7% of BrdU-positive cells in endothelium and media occurred at 7 days after arteriotomy, while the apoptotic index peaked at 3 days after injury (p<0.05). Our results highlight a persistent DNA damage presumably related to a temporary decreased expression of the DNA repair machinery and of the antioxidant enzyme catalase, playing a role in stenosis progression.
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Wang K, Gong P, Liu L, Gong S, Liu J, Shen J, Luo G. Effect of 2-TeCD on the expression of adhesion molecules in human umbilical vein endothelial cells under the stimulation of tumor necrosis factor-α. Int Immunopharmacol 2009; 9:1087-91. [DOI: 10.1016/j.intimp.2009.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 04/21/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
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Monaghan-Benson E, Burridge K. The regulation of vascular endothelial growth factor-induced microvascular permeability requires Rac and reactive oxygen species. J Biol Chem 2009; 284:25602-11. [PMID: 19633358 DOI: 10.1074/jbc.m109.009894] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Vascular permeability is a complex process involving the coordinated regulation of multiple signaling pathways in the endothelial cell. It has long been documented that vascular endothelial growth factor (VEGF) greatly enhances microvascular permeability; however, the molecular mechanisms controlling VEGF-induced permeability remain unknown. Treatment of microvascular endothelial cells with VEGF led to an increase in reactive oxygen species (ROS) production. ROS are required for VEGF-induced permeability as treatment with the free radical scavenger, N-acetylcysteine, inhibited this effect. Additionally, treatment with VEGF caused ROS-dependent tyrosine phosphorylation of both vascular-endothelial (VE)-cadherin and beta-catenin. Rac1 was required for the VEGF-induced increase in permeability and adherens junction protein phosphorylation. Knockdown of Rac1 inhibited VEGF-induced ROS production consistent with Rac lying upstream of ROS in this pathway. Collectively, these data suggest that VEGF leads to a Rac-mediated generation of ROS, which, in turn, elevates the tyrosine phosphorylation of VE-cadherin and beta-catenin, ultimately regulating adherens junction integrity.
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Affiliation(s)
- Elizabeth Monaghan-Benson
- Department of Cell and Developmental Biology and Lineberger Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-7295, USA.
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Abstract
The endothelium is an important component of vascular homeostasis that is a target for injury in the setting of vascular disease. One means of promoting a maladaptive endothelial cell phenotype such as that seen in atherosclerosis is excess oxidative stress. Although this term once was almost exclusively used to describe low-density lipoprotein (LDL) and lipid oxidation in the vasculature, we now understand that the intracellular oxidant milieu is an important modulator of vascular cell function. Indeed, considerable data indicate that reactive oxygen species (ROS) are an important means of cellular signaling, although the precise mechanisms whereby ROS accomplish this are still under investigation. In this review, the data linking ROS to kinase activation and cell signaling in the endothelium is discussed, with a particular emphasis on the roles of protein thiol modification.
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Affiliation(s)
- Kai Chen
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, USA
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Niwa K, Sakai J, Karino T, Aonuma H, Watanabe T, Ohyama T, Inanami O, Kuwabara M. Reactive oxygen species mediate shear stress-induced fluid-phase endocytosis in vascular endothelial cells. Free Radic Res 2009; 40:167-74. [PMID: 16390826 DOI: 10.1080/10715760500474287] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To elucidate the role of shear stress in fluid-phase endocytosis of vascular endothelial cells (EC), we used a rotating-disk shearing apparatus to investigate the effects of shear stress on the uptake of lucifer yellow (LY) by cultured bovine aortic endothelial cells (BAEC). Exposure of EC to shear stress (area-mean value of 10 dynes/cm2) caused an increase in LY uptake that was abrogated by the antioxidant, N-acetyl-L-cysteine (NAC), the NADPH oxidase inhibitor, acetovanillone, and two inhibitors of protein kinase C (PKC), calphostin C and GF109203X. These results suggest that fluid-phase endocytosis is regulated by both reactive oxygen species (ROS) and PKC. Shear stress increased both ROS production and PKC activity in EC, and the increase in ROS was unaffected by calphostin C or GF109203X, whereas the activation of PKC was reduced by NAC and acetovanillone. We conclude that shear stress-induced increase in fluid-phase endocytosis is mediated via ROS generation followed by PKC activation in EC.
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Affiliation(s)
- Koichi Niwa
- Faculty of Bioindustry, Tokyo University of Agriculture, Department of Food Science and Technology, 196 Yasaka, Abashiri, 099-2493, Japan.
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Lee KH, Kim SW, Kim JR. Reactive oxygen species regulate urokinase plasminogen activator expression and cell invasion via mitogen-activated protein kinase pathways after treatment with hepatocyte growth factor in stomach cancer cells. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2009; 28:73. [PMID: 19497102 PMCID: PMC2698863 DOI: 10.1186/1756-9966-28-73] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 06/04/2009] [Indexed: 11/10/2022]
Abstract
Background Reactive oxygen species (ROS) are closely associated with the intracellular signal cascade, thus strongly implicating involvement in tumor progression. However, the mechanism by which ROS are generated and how ROS target downstream molecules to trigger tumor metastasis is unclear. In this study, we investigated the underlying signal pathways in ROS-induced urokinase plasminogen activator (uPA) expression in the human gastric cancer cells, NUGC-3 and MKN-28. Methods and Results Intracellular ROS, as determined using the fluorescent probe, 2'-7' dichlorofluorescein diacetate, decreased after treatment with hepatocyte growth factor (HGF). We confirmed that Rac-1 regulated ROS production after activation of the AKT pathway with HGF. Exogenously added H2O2 promoted the expression of HGF, but not in a dose-dependent manner and also showed negative expression of HGF after co-treatment with H2O2 and HGF. Treatment with NAC, an intracellular free radical scavenger, decreased the enhancement of uPA production and tumor invasion in both cells. We clarified the downstream pathways regulated by ROS after treatment with H2O2, which showed negative control between FRK and p38 kinase activities for uPA regulation. Conclusion HGF regulates Rac-1-induced ROS production through the Akt pathway and ROS regulates uPA production and invasion via MAP kinase, which provides novel insight into the mechanisms underlying the progression of gastric cancer.
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Affiliation(s)
- Kyung Hee Lee
- Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu, Korea.
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Fitzpatrick PA, Guinan AF, Walsh TG, Murphy RP, Killeen MT, Tobin NP, Pierotti AR, Cummins PM. Down-regulation of neprilysin (EC3.4.24.11) expression in vascular endothelial cells by laminar shear stress involves NADPH oxidase-dependent ROS production. Int J Biochem Cell Biol 2009; 41:2287-94. [PMID: 19464387 DOI: 10.1016/j.biocel.2009.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 05/14/2009] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
Neprilysin (NEP, neutral endopeptidase, EC3.4.24.11), a zinc metallopeptidase expressed on the surface of endothelial cells, influences vascular homeostasis primarily through regulated inactivation of natriuretic peptides and bradykinin. Earlier in vivo studies reporting on the anti-atherosclerotic effects of NEP inhibition and on the atheroprotective effects of flow-associated laminar shear stress (LSS) have lead us to hypothesize that the latter hemodynamic stimulus may serve to down-regulate NEP levels within the vascular endothelium. To address this hypothesis, we have undertaken an investigation of the effects of LSS on NEP expression in vitro in bovine aortic endothelial cells (BAECs), coupled with an examination of the signalling mechanism putatively mediating these effects. BAECs were exposed to physiological levels of LSS (10 dynes/cm(2), 24h) and harvested for analysis of NEP expression using real-time PCR, Western blotting, and immunocytochemistry. Relative to unsheared controls, NEP mRNA and protein were substantially down-regulated by LSS (>or=50%), events which could be prevented by treatment of BAECs with either N-acetylcysteine, superoxide dismutase, or catalase, implicating reactive oxygen species (ROS) involvement. Employing pharmacological and molecular inhibition strategies, the signal transduction pathway mediating shear-dependent NEP suppression was also examined, and roles implicated for G beta gamma, Rac1, and NADPH oxidase activation in these events. Treatment of static BAECs with angiotensin-II, a potent stimulus for NADPH oxidase activation, mimicked the suppressive effects of shear on NEP expression, further supporting a role for NADPH oxidase-dependent ROS production. Interestingly, inhibition of receptor tyrosine kinase signalling had no effect. In conclusion, we confirm for the first time that NEP expression is down-regulated in vascular endothelial cells by physiological laminar shear, possibly via a mechanotransduction mechanism involving NADPH oxidase-induced ROS production.
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Affiliation(s)
- Paul A Fitzpatrick
- School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland
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42
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Han Z, Varadharaj S, Giedt RJ, Zweier JL, Szeto HH, Alevriadou BR. Mitochondria-derived reactive oxygen species mediate heme oxygenase-1 expression in sheared endothelial cells. J Pharmacol Exp Ther 2009; 329:94-101. [PMID: 19131585 DOI: 10.1124/jpet.108.145557] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Bovine aortic endothelial cells (ECs) respond to nitric oxide (NO) donors by activating the redox-sensitive NF-E2-related factor 2/antioxidant response element pathway and up-regulating heme oxygenase (HO)-1 expression. EC exposure to steady laminar shear stress causes a sustained increase in NO, a transient increase in reactive oxygen species (ROS), and activation of the HO-1 gene. Because steady laminar flow increases the mitochondrial superoxide (O(2)(*-)) production, we hypothesized that mitochondria-derived ROS play a role in shear-induced HO-1 expression. Flow (10 dynes/cm(2), 6 h)-induced expression of HO-1 protein was abolished when BAECs were preincubated and sheared in the presence of either N(G)-nitro-L-arginine methyl ester or N-acetyl-L-cysteine, suggesting that either NO or ROS up-regulates HO-1. Ebselen and diphenylene iodonium blocked HO-1 expression, and uric acid had no effect. The mitochondrial electron transport chain inhibitors, myxothiazol, rotenone, or antimycin A, and the mitochondria-targeted antioxidant peptide, Szeto-Schiller (SS)-31, which scavenges O(2)(*-), hydrogen peroxide (H(2)O(2)), peroxynitrite, and hydroxyl radicals, markedly inhibited the increase in HO-1 expression. These data collectively suggest that mitochondrial H(2)O(2) mediates the HO-1 induction. MitoSOX and 2',7'-dichlorofluorescin (DCF) fluorescence showed that mitochondrial O(2)(*-) levels and intracellular peroxides, respectively, are higher in sheared ECs compared with static controls and, in part, dependent on NO. SS-31 significantly inhibited both the shear-induced MitoSOX and DCF fluorescence signals. Either phosphatidylinositol 3-kinase or mitogen-activated protein kinase cascade inhibitors blocked the HO-1 induction. In conclusion, under shear, EC mitochondria-derived H(2)O(2) diffuses to the cytosol, where it initiates oxidative signaling leading to HO-1 up-regulation and maintenance of the atheroprotective EC status.
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Affiliation(s)
- Zhaosheng Han
- Davis Heart and Lung Research Institute, Department of Biomedical Engineering, Ohio State University, Columbus, OH 43210, USA
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Kim JH, Suk MH, Yoon DW, Kim HY, Jung KH, Kang EH, Lee SY, Lee SY, Suh IB, Shin C, Shim JJ, In KH, Yoo SH, Kang KH. Inflammatory and transcriptional roles of poly (ADP-ribose) polymerase in ventilator-induced lung injury. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:R108. [PMID: 18718025 PMCID: PMC2575597 DOI: 10.1186/cc6995] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/14/2008] [Accepted: 08/22/2008] [Indexed: 02/01/2023]
Abstract
Introduction Poly (ADP-ribose) polymerase (PARP) participates in inflammation by cellular necrosis and the nuclear factor-kappa-B (NF-κB)-dependent transcription. The purpose of this study was to examine the roles of PARP in ventilator-induced lung injury (VILI) in normal mice lung. Methods Male C57BL/6 mice were divided into four groups: sham tracheostomized (sham), lung-protective ventilation (LPV), VILI, and VILI with PARP inhibitor PJ34 pretreatment (PJ34+VILI) groups. Mechanical ventilation (MV) settings were peak inspiratory pressure (PIP) 15 cm H2O + positive end-expiratory pressure (PEEP) 3 cm H2O + 90 breaths per minute for the LPV group and PIP 40 cm H2O + PEEP 0 cm H2O + 90 breaths per minute for the VILI and PJ34+VILI groups. After 2 hours of MV, acute lung injury (ALI) score, wet-to-dry (W/D) weight ratio, PARP activity, and dynamic compliance (CD) were recorded. Tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), myeloperoxidase (MPO) activity, and nitrite/nitrate (NOX) in the bronchoalveolar lavage fluid and NF-κB DNA-binding activity in tissue homogenates were measured. Results The VILI group showed higher ALI score, W/D weight ratio, MPO activity, NOX, and concentrations of TNF-α and IL-6 along with lower CD than the sham and LPV groups (P < 0.05). In the PJ34+VILI group, PJ34 pretreatment improved all histopathologic ALI, inflammatory profiles, and pulmonary dynamics (P < 0.05). NF-κB activity was increased in the VILI group as compared with the sham and LPV groups (P < 0.05) and was decreased in the PJ34+VILI group as compared with the VILI group (P = 0.009). Changes in all parameters were closely correlated with the PARP activity (P < 0.05). Conclusion Overactivation of PARP plays an important role in the inflammatory and transcriptional pathogenesis of VILI, and PARP inhibition has potentially beneficial effects on the prevention and treatment of VILI.
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Affiliation(s)
- Je Hyeong Kim
- Division of Pulmonary, Sleep and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, 516, Gojan 1-dong, Danwon-gu, Ansan 425-707, Republic of Korea
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Orr AW, Hahn C, Blackman BR, Schwartz MA. p21-activated kinase signaling regulates oxidant-dependent NF-kappa B activation by flow. Circ Res 2008; 103:671-9. [PMID: 18669917 DOI: 10.1161/circresaha.108.182097] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Disturbed blood flow induces inflammatory gene expression in endothelial cells, which promotes atherosclerosis. Flow stimulates the proinflammatory transcription factor nuclear factor (NF)-kappaB through integrin- and Rac-dependent production of reactive oxygen species (ROS). Previous work demonstrated that NF-kappaB activation by flow is matrix-specific, occurring in cells on fibronectin but not collagen. Activation of p21-activated kinase (PAK) followed the same matrix-dependent pattern. We now show that inhibiting PAK in cells on fibronectin blocked NF-kappaB activation by both laminar and oscillatory flow in vitro and at sites of disturbed flow in vivo. Constitutively active PAK rescued flow-induced NF-kappaB activation in cells on collagen. Surprisingly, PAK was not required for flow-induced ROS production. Instead, PAK modulated the ability of ROS to activate the NF-kappaB pathway. These data demonstrate that PAK controls NF-kappaB activation by modulating the sensitivity of cells to ROS.
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Affiliation(s)
- A Wayne Orr
- Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
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Caveolae are an essential component of the pathway for endothelial cell signaling associated with abrupt reduction of shear stress. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1866-75. [PMID: 18573285 DOI: 10.1016/j.bbamcr.2008.05.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 05/01/2008] [Accepted: 05/06/2008] [Indexed: 01/10/2023]
Abstract
Abrupt cessation of flow representing the acute loss of shear stress (simulated ischemia) to flow-adapted pulmonary microvascular endothelial cells (PMVEC) leads to reactive oxygen species (ROS) generation that signals for EC proliferation. We evaluated the role of caveolin-1 on this cellular response with mouse PMVEC that were preconditioned for 72 h to laminar flow at 5 dyn/cm(2) followed by stop of flow ("ischemia"). Preconditioning resulted in a 2.7-fold increase in cellular expression of K(ATP) (K(IR) 6.2) channels but no change in expression level of caveolin-1, gp91(phox), or MAP kinases. The initial response to ischemia in wild type cells was cell membrane depolarization that was abolished by gene targeting of K(IR) 6.2. The subsequent response was increased ROS production associated with activation of NADPH oxidase (NOX2) and then phosphorylation of MAP kinases (Erk, JNK). After 24 h of ischemia in wild type cells, the cell proliferation index increased 2.5 fold and the % of cells in S+G(2)/M phases increased 6-fold. This signaling cascade (cell membrane depolarization, ROS production, MAP kinase activation and cell proliferation) was abrogated in caveolin-1 null PMVEC or by treatment of wild type cells with filipin. These studies indicate that caveolin-1 functions as a shear sensor in flow-adapted EC resulting in ROS-mediated cell signaling and endothelial cell proliferation following the abrupt reduction in flow.
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Jones CI, Han Z, Presley T, Varadharaj S, Zweier JL, Ilangovan G, Alevriadou BR. Endothelial cell respiration is affected by the oxygen tension during shear exposure: role of mitochondrial peroxynitrite. Am J Physiol Cell Physiol 2008; 295:C180-91. [PMID: 18480296 DOI: 10.1152/ajpcell.00549.2007] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cultured vascular endothelial cell (EC) exposure to steady laminar shear stress results in peroxynitrite (ONOO(-)) formation intramitochondrially and inactivation of the electron transport chain. We examined whether the "hyperoxic state" of 21% O(2), compared with more physiological O(2) tensions (Po(2)), increases the shear-induced nitric oxide (NO) synthesis and mitochondrial superoxide (O(2)(*-)) generation leading to ONOO(-) formation and suppression of respiration. Electron paramagnetic resonance oximetry was used to measure O(2) consumption rates of bovine aortic ECs sheared (10 dyn/cm(2), 30 min) at 5%, 10%, or 21% O(2) or left static at 5% or 21% O(2). Respiration was inhibited to a greater extent when ECs were sheared at 21% O(2) than at lower Po(2) or left static at different Po(2). Flow in the presence of an endothelial NO synthase (eNOS) inhibitor or a ONOO(-) scavenger abolished the inhibitory effect. EC transfection with an adenovirus that expresses manganese superoxide dismutase in mitochondria, and not a control virus, blocked the inhibitory effect. Intracellular and mitochondrial O(2)(*-) production was higher in ECs sheared at 21% than at 5% O(2), as determined by dihydroethidium and MitoSOX red fluorescence, respectively, and the latter was, at least in part, NO-dependent. Accumulation of NO metabolites in media of ECs sheared at 21% O(2) was modestly increased compared with ECs sheared at lower Po(2), suggesting that eNOS activity may be higher at 21% O(2). Hence, the hyperoxia of in vitro EC flow studies, via increased NO and mitochondrial O(2)(*-) production, leads to enhanced ONOO(-) formation intramitochondrially and suppression of respiration.
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Affiliation(s)
- Charles I Jones
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
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47
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Dentelli P, Rosso A, Zeoli A, Gambino R, Pegoraro L, Pagano G, Falcioni R, Brizzi MF. Oxidative stress-mediated mesangial cell proliferation requires RAC-1/reactive oxygen species production and beta4 integrin expression. J Biol Chem 2007; 282:26101-10. [PMID: 17604276 DOI: 10.1074/jbc.m703132200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipid abnormalities and oxidative stress, by stimulating mesangial cell (MC) proliferation, can contribute to the development of diabetes-associated renal disease. In this study we investigated the molecular events elicited by oxidized low density lipoproteins (ox-LDL) in MC. We demonstrate that in MC cultured in the presence of ox-LDL, survival and mitogenic signals on Akt and Erk1/2 MAPK pathways are induced, respectively. Moreover, as shown by the expression of the dominant negative Rac-1 construct, we first report that ox-LDL-mediated cell survival and cell cycle progression depend on Rac-1 GTPase-mediated reactive oxygen species production and on epidermal growth factor receptor transactivation. By silencing Akt and blocking Erk1/2 MAPK pathways, we also demonstrate that these signals are downstream to Rac-1/reactive oxygen species production and epidermal growth factor receptor activation. Finally, by endogenous depletion of beta4 integrin, expressed in MC, we provide evidence that the expression of this adhesion molecule is essential for ox-LDL-mediated MC dysfunction. Our data identify a novel signaling pathway involved in oxidative stress-induced diabetes-associated renal disease and provide the rationale for therapeutically targeting beta4 integrin.
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Affiliation(s)
- Patrizia Dentelli
- Department of Internal Medicine, University of Torino, Corso Dogliotti 14, 10126 Torino, Italy
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Jones CI, Zhu H, Martin SF, Han Z, Li Y, Alevriadou BR. Regulation of Antioxidants and Phase 2 Enzymes by Shear-Induced Reactive Oxygen Species in Endothelial Cells. Ann Biomed Eng 2007; 35:683-93. [PMID: 17340195 DOI: 10.1007/s10439-007-9279-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 02/01/2007] [Indexed: 01/19/2023]
Abstract
Exposure of vascular endothelial cells (ECs) to steady laminar shear stress activates the NF-E2-related factor 2 (Nrf2) which binds to the antioxidant response element (ARE) and upregulates the expression of several genes. The onset of shear is known to increase the EC reactive oxygen species (ROS) production, and oxidative stress can activate the ARE. ARE-regulated genes include phase 2 enzymes, such as glutathione-S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), and antioxidants, such as glutathione reductase (GR), glutathione peroxidase (GPx) and catalase. We examined how shear stress affects the antioxidant/phase 2 enzyme activities and whether ROS mediate these effects. ROS production, measured by dichlorofluorescin fluorescence, depended on level and time of shear exposure and EC origin, and was inhibited by either an endothelial nitric oxide synthase (eNOS) inhibitor or a superoxide dismutase (SOD) mimetic and peroxynitrite (ONOO-) scavenger. Shear stress (10 dynes/cm2, 16 h) significantly increased the NQO1 activity, did not change significantly the glutathione (GSH) content, and significantly decreased the GR, GPx, GST and catalase activities in human umbilical vein ECs. Either eNOS inhibition or superoxide radical (O2*-)/ONOO- scavenging differentially modulated the shear effects on enzyme activities suggesting that the intracellular redox status coordinates the shear-induced expression of cytoprotective genes.
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Affiliation(s)
- Charles I Jones
- Department of Internal Medicine, Davis Heart and Lung Research Institute, Columbus, OH 43210, USA
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Dworakowski R, Anilkumar N, Zhang M, Shah AM. Redox signalling involving NADPH oxidase-derived reactive oxygen species. Biochem Soc Trans 2007; 34:960-4. [PMID: 17052237 DOI: 10.1042/bst0340960] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Increased oxidative stress plays an important role in the pathophysiology of many diseases such as atherosclerosis, diabetes mellitus, myocardial infarction and heart failure. In addition to the well-known damaging effects of oxygen-free radicals, ROS (reactive oxygen species) also have signalling roles, acting as second messengers that modulate the activity of diverse intracellular signalling pathways and transcription factors, thereby inducing changes in cell phenotype. NADPH oxidases appear to be especially important sources of ROS involved in redox signalling. Seven NADPH oxidase isoforms, known as Noxs (NAPDH oxidases), are expressed in a cell- and tissue-specific fashion. These oxidases are thought to subserve distinct functions as a result of their tightly regulated activation (e.g. by neurohormonal and growth factors and mechanical stimuli) and their specific coupling with distinct downstream signalling pathways. In the present paper, we review the structure and mechanisms of activation of NADPH oxidases and consider their involvement in redox signalling, focusing mainly on the cardiovascular system.
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Affiliation(s)
- R Dworakowski
- Cardiovascular Division, Department of Cardiology, King's College London School of Medicine, Bessemer Road, London SE5 9PJ, UK
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Ueno S, Campbell J, Fausto N. Reactive oxygen species derived from NADPH oxidase system is not essential for liver regeneration after partial hepatectomy. J Surg Res 2006; 136:260-5. [PMID: 17046793 DOI: 10.1016/j.jss.2006.05.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 05/09/2006] [Accepted: 05/26/2006] [Indexed: 11/29/2022]
Abstract
BACKGROUND There is suggestive evidence that reactive oxygen species may play a role in the initiation of liver regeneration via a kupffer cell-mediated mechanism involving TNFa and NF-kappa B. In mammalian cells, a major source of reactive oxygen species derives from the membrane-bound NADPH oxidase system (no protein de novo synthesis is required) and it is known that the low levels of oxidants produced through NADPH oxidase play a role in liver cell proliferation because of peroxisome proliferators. METHODS We used knockout mice lacking Cybb: subunit of NADPH oxidase to determine whether signaling at the start of liver regeneration after partial hepatectomy (PH) involves reactive oxygen species produced through NADPH oxidase and to analyze in more detail the abnormalities caused by lack of its component, which is required for the initiation of liver regeneration. RESULTS Lack of Cybb had little effect on NF-kappa B and STAT3 binding, and no effect in TNFa and interleukin-6 production after PH. Cybb KO mice had normal liver structure and similar levels of hepatocyte DNA replication as those of wild type mice. CONCLUSIONS We conclude that NADPH oxidase is not necessary for liver regeneration after PH. It is likely that there is a potential pathway not including NADPH oxidase to activate NF-kappa B and STAT3 binding for the initiation of liver regeneration after PH.
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Affiliation(s)
- Shinichi Ueno
- Department of Pathology, University of Washington School of Medicine, Seattle, Washington, USA.
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