51
|
Evans PC, Gijsen FJH, Wentzel JJ, van der Heiden K. Biomechanics in vascular biology and cardiovascular disease. Thromb Haemost 2016; 115:465-6. [PMID: 26864973 DOI: 10.1160/th16-01-0075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 11/05/2022]
|
52
|
Di Marco LY, Venneri A, Farkas E, Evans PC, Marzo A, Frangi AF. Vascular dysfunction in the pathogenesis of Alzheimer's disease--A review of endothelium-mediated mechanisms and ensuing vicious circles. Neurobiol Dis 2015; 82:593-606. [PMID: 26311408 DOI: 10.1016/j.nbd.2015.08.014] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 07/23/2015] [Accepted: 08/17/2015] [Indexed: 12/17/2022] Open
Abstract
Late-onset dementia is a major health concern in the ageing population. Alzheimer's disease (AD) accounts for the largest proportion (65-70%) of dementia cases in the older population. Despite considerable research effort, the pathogenesis of late-onset AD remains unclear. Substantial evidence suggests that the neurodegenerative process is initiated by chronic cerebral hypoperfusion (CCH) caused by ageing and cardiovascular conditions. CCH causes reduced oxygen, glucose and other nutrient supply to the brain, with direct damage not only to the parenchymal cells, but also to the blood-brain barrier (BBB), a key mediator of cerebral homeostasis. BBB dysfunction mediates the indirect neurotoxic effects of CCH by promoting oxidative stress, inflammation, paracellular permeability, and dysregulation of nitric oxide, a key regulator of regional blood flow. As such, BBB dysfunction mediates a vicious circle in which cerebral perfusion is reduced further and the neurodegenerative process is accelerated. Endothelial interaction with pericytes and astrocytes could also play a role in the process. Reciprocal interactions between vascular dysfunction and neurodegeneration could further contribute to the development of the disease. A comprehensive overview of the complex scenario of interacting endothelium-mediated processes is currently lacking, and could prospectively contribute to the identification of adequate therapeutic interventions. This study reviews the current literature of in vitro and ex vivo studies on endothelium-mediated mechanisms underlying vascular dysfunction in AD pathogenesis, with the aim of presenting a comprehensive overview of the complex network of causative relationships. Particular emphasis is given to vicious circles which can accelerate the process of neurovascular degeneration.
Collapse
|
53
|
Hoefer IE, Steffens S, Ala-Korpela M, Bäck M, Badimon L, Bochaton-Piallat ML, Boulanger CM, Caligiuri G, Dimmeler S, Egido J, Evans PC, Guzik T, Kwak BR, Landmesser U, Mayr M, Monaco C, Pasterkamp G, Tuñón J, Weber C. Novel methodologies for biomarker discovery in atherosclerosis. Eur Heart J 2015; 36:2635-42. [DOI: 10.1093/eurheartj/ehv236] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/18/2015] [Indexed: 01/21/2023] Open
|
54
|
Kidher E, Jarral OA, Harling L, Anderson JR, Chukwuemeka A, Ashrafian H, Evans PC, Athanasiou T. NR2 antibody is associated with quality of life in aortic valve replacement. Asian Cardiovasc Thorac Ann 2015; 23:690-700. [PMID: 25931568 DOI: 10.1177/0218492315583189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The relationship between the potential brain injury biomarker N-methyl-D-aspartate receptor antibody and quality of life has never been assessed. METHODS We measured serum N-methyl-D-aspartate receptor antibody levels preoperatively in patients undergoing aortic valve replacement. Quality of life was scored using the Short Form-36 and European Quality of Life 5-Dimensions questionnaires pre- and postoperatively. We analyzed the antibody levels as a continuous variable and as a dichotomous variable with 1.8 ng mL(-1) as the cutoff. RESULTS Fifty-two patients (15 females) with a mean age of 71 ± 8.4 years were recruited for this study. Forty-eight (92%) patients attended the follow-up visit (405 ± 161 days). No mortality or severe neurological event was recorded. In both quality-of-life instruments, the low antibody level group (n = 35) had significantly better scores than the high antibody level group (n = 17) preoperatively. Postoperatively, the scores for both groups improved; however, the low antibody level group continued to score significantly better in most of the physical and mental health domains (p = 0.04 to <0.001). Multiple regression analyses revealed that antibody level and the 1.8 ng mL(-1) cutoff were independently related to quality of life (pre- and postoperatively). CONCLUSIONS Higher N-methyl-D-aspartate receptor antibody levels in aortic valve replacement patients are independently related to poorer quality of life pre- and postoperatively.
Collapse
|
55
|
Mylroie H, Dumont O, Bauer A, Thornton CC, Mackey J, Calay D, Hamdulay SS, Choo JR, Boyle JJ, Samarel AM, Randi AM, Evans PC, Mason JC. PKCε-CREB-Nrf2 signalling induces HO-1 in the vascular endothelium and enhances resistance to inflammation and apoptosis. Cardiovasc Res 2015; 106:509-19. [PMID: 25883219 PMCID: PMC4431664 DOI: 10.1093/cvr/cvv131] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 04/03/2015] [Indexed: 12/25/2022] Open
Abstract
AIMS Vascular injury leading to endothelial dysfunction is a characteristic feature of chronic renal disease, diabetes mellitus, and systemic inflammatory conditions, and predisposes to apoptosis and atherogenesis. Thus, endothelial dysfunction represents a potential therapeutic target for atherosclerosis prevention. The observation that activity of either protein kinase C epsilon (PKCε) or haem oxygenase-1 (HO-1) enhances endothelial cell (EC) resistance to inflammation and apoptosis led us to test the hypothesis that HO-1 is a downstream target of PKCε. METHODS AND RESULTS Expression of constitutively active PKCε in human EC significantly increased HO-1 mRNA and protein, whereas conversely aortas or cardiac EC from PKCε-deficient mice exhibited reduced HO-1 when compared with wild-type littermates. Angiotensin II activated PKCε and induced HO-1 via a PKCε-dependent pathway. PKCε activation significantly attenuated TNFα-induced intercellular adhesion molecule-1, and increased resistance to serum starvation-induced apoptosis. These responses were reversed by the HO antagonist zinc protoporphyrin IX. Phosphokinase antibody array analysis identified CREB1((Ser133)) phosphorylation as a PKCε signalling intermediary, and cAMP response element-binding protein 1 (CREB1) siRNA abrogated PKCε-induced HO-1 up-regulation. Likewise, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was identified as a PKCε target using nuclear translocation and DNA-binding assays, and Nrf2 siRNA prevented PKCε-mediated HO-1 induction. Moreover, depletion of CREB1 inhibited PKCε-induced Nrf2 DNA binding, suggestive of transcriptional co-operation between CREB1 and Nrf2. CONCLUSIONS PKCε activity in the vascular endothelium regulates HO-1 via a pathway requiring CREB1 and Nrf2. Given the potent protective actions of HO-1, we propose that this mechanism is an important contributor to the emerging role of PKCε in the maintenance of endothelial homeostasis and resistance to injury.
Collapse
|
56
|
Cuhlmann S, Gsell W, Van der Heiden K, Habib J, Tremoleda JL, Khalil M, Turkheimer F, Meens MJ, Kwak BR, Bird J, Davenport AP, Clark J, Haskard D, Krams R, Jones H, Evans PC. In vivo mapping of vascular inflammation using the translocator protein tracer 18F-FEDAA1106. Mol Imaging 2015; 13. [PMID: 24825602 DOI: 10.2310/7290.2014.00014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Noninvasive imaging methods are required to monitor the inflammatory content of atherosclerotic plaques. FEDAA1106 (N-(5-fluoro-2-phenoxyphenyl)-N-(2-(2-fluoroethoxy)-5-methoxybenzyl) acetamide) is a selective ligand for TSPO-18kDa (also known as peripheral benzodiazepine receptor), which is expressed by activated macrophages. We compared 18F-FEDAA1106 and 2-deoxy-2-[18F]fluoro-d-glucose (18F-FDG, a marker of glucose metabolism) for positron emission tomographic (PET) imaging of vascular inflammation. This was tested using a murine model in which focal inflammation was induced in the carotid artery via placement of a constrictive cuff. Immunostaining revealed CD68-positive cells (macrophages) at a disturbed flow site located downstream from the cuff. Dynamic PET imaging using 18F-FEDAA1106 or 18F-FDG was registered to anatomic data generated by computed tomographic (CT)/CT angiography. Standardized uptake values were significantly increased at cuffed compared to contralateral arteries using either 18F-FEDAA1106 (p < .01) or FDG (p < .05). However, the 18F-FEDAA1106 signal was significantly higher at the inflamed disturbed flow region compared to the noninflamed uniform flow regions, whereas differences in FDG uptake were less distinct. We conclude that 18F-FEDAA1106 can be used in vivo for detection of vascular inflammation. Moreover, the signal pattern of 18F-FEDAA1106 corresponded with vascular inflammation more specifically than FDG uptake.
Collapse
|
57
|
Enesa K, Moll HP, Luong L, Ferran C, Evans PC. A20 suppresses vascular inflammation by recruiting proinflammatory signaling molecules to intracellular aggresomes. FASEB J 2015; 29:1869-78. [PMID: 25667218 DOI: 10.1096/fj.14-258533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 12/24/2014] [Indexed: 12/16/2022]
Abstract
A20 protects against pathologic vascular remodeling by inhibiting the inflammatory transcription factor NF-κB. A20's function has been attributed to ubiquitin editing of receptor-interacting protein 1 (RIP1) to influence activity/stability. The validity of this mechanism was tested using a murine model of transplant vasculopathy and human cells. Mouse C57BL/6 aortae transduced with adenoviruses containing A20 (or β-galactosidase as a control) were allografted into major histocompatibility complex-mismatched BALB/c mice. Primary endothelial cells, smooth muscle cells, or transformed epithelial cells (all human) were transfected with wild-type A20 or with catalytically inactive mutants as a control. NF-κB activity and intracellular localization of RIP1 was monitored by reporter gene assay, immunofluorescent staining, and Western blotting. Native and catalytically inactive versions of A20 had similar inhibitory effects on NF-κB activity (-70% vs. -76%; P > 0.05). A20 promoted localization of RIP1 to insoluble aggresomes in murine vascular allografts and in human cells (53% vs. 0%) without altering RIP1 expression, and this process was increased by the assembly of polyubiquitin chains (87% vs. 28%; P < 0.05). A20 captures polyubiquitinated signaling intermediaries in insoluble aggresomes, thus reducing their bioavailability for downstream NF-κB signaling. This novel mechanism contributes to protection from vasculopathy in transplanted organs treated with exogenous A20.
Collapse
|
58
|
Gauci I, Mahmoud M, Duckles H, Feng S, Hsiao S, Evans PC. Disturbed flow influences endothelial activation by inducing homeobox transcription factors. Atherosclerosis 2014. [DOI: 10.1016/j.atherosclerosis.2014.10.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
59
|
Kwak BR, Bäck M, Bochaton-Piallat ML, Caligiuri G, Daemen MJAP, Davies PF, Hoefer IE, Holvoet P, Jo H, Krams R, Lehoux S, Monaco C, Steffens S, Virmani R, Weber C, Wentzel JJ, Evans PC. Biomechanical factors in atherosclerosis: mechanisms and clinical implications. Eur Heart J 2014; 35:3013-20, 3020a-3020d. [PMID: 25230814 DOI: 10.1093/eurheartj/ehu353] [Citation(s) in RCA: 294] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Blood vessels are exposed to multiple mechanical forces that are exerted on the vessel wall (radial, circumferential and longitudinal forces) or on the endothelial surface (shear stress). The stresses and strains experienced by arteries influence the initiation of atherosclerotic lesions, which develop at regions of arteries that are exposed to complex blood flow. In addition, plaque progression and eventually plaque rupture is influenced by a complex interaction between biological and mechanical factors-mechanical forces regulate the cellular and molecular composition of plaques and, conversely, the composition of plaques determines their ability to withstand mechanical load. A deeper understanding of these interactions is essential for designing new therapeutic strategies to prevent lesion development and promote plaque stabilization. Moreover, integrating clinical imaging techniques with finite element modelling techniques allows for detailed examination of local morphological and biomechanical characteristics of atherosclerotic lesions that may be of help in prediction of future events. In this ESC Position Paper on biomechanical factors in atherosclerosis, we summarize the current 'state of the art' on the interface between mechanical forces and atherosclerotic plaque biology and identify potential clinical applications and key questions for future research.
Collapse
|
60
|
Mahmoud M, Kim R, De Luca A, Gauci I, Hsiao S, Evans PC. P470Disturbed flow promotes endothelial cell injury via the induction of developmental genes. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu091.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
61
|
Hsiao S, Tovar-Lopez FJ, Gunn J, Spencer T, Halliday I, Perrault C, Evans PC. 292Endothelial cell forward migration in a disturbed wall shear stress environment is promoted by ROCK inhibition. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu087.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
62
|
Bryan MT, Duckles H, Feng S, Hsiao ST, Kim HR, Serbanovic-Canic J, Evans PC. Mechanoresponsive networks controlling vascular inflammation. Arterioscler Thromb Vasc Biol 2014; 34:2199-205. [PMID: 24947523 DOI: 10.1161/atvbaha.114.303424] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Atherosclerosis is a chronic inflammatory disease of arteries that develops preferentially at branches and bends that are exposed to disturbed blood flow. Vascular function is modified by flow, in part, via the generation of mechanical forces that alter multiple physiological processes in endothelial cells. Shear stress has profound effects on vascular inflammation; high uniform shear stress prevents leukocyte recruitment to the vascular wall by reducing endothelial expression of adhesion molecules and other inflammatory proteins, whereas low oscillatory shear stress has the opposite effects. Here, we review the molecular mechanisms that underpin the effects of shear stress on endothelial inflammatory responses. They include shear stress regulation of inflammatory mitogen-activated protein kinase and nuclear factor-κB signaling. High shear suppresses these pathways through the induction of several negative regulators of inflammation, whereas low shear promotes inflammatory signaling. Furthermore, we summarize recent studies indicating that inflammatory signaling is highly sensitive to pulse wave frequencies, magnitude, and direction of flow. Finally, the importance of systems biology approaches (including omics studies and functional screening) to identify novel mechanosensitive pathways is discussed.
Collapse
|
63
|
Amini N, Boyle JJ, Moers B, Warboys CM, Malik TH, Zakkar M, Francis SE, Mason JC, Haskard DO, Evans PC. Requirement of JNK1 for endothelial cell injury in atherogenesis. Atherosclerosis 2014; 235:613-8. [PMID: 24956536 PMCID: PMC4104040 DOI: 10.1016/j.atherosclerosis.2014.05.950] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 04/11/2014] [Accepted: 05/22/2014] [Indexed: 12/24/2022]
Abstract
Objective The c-Jun N-terminal kinase (JNK) family regulates fundamental physiological processes including apoptosis and metabolism. Although JNK2 is known to promote foam cell formation during atherosclerosis, the potential role of JNK1 is uncertain. We examined the potential influence of JNK1 and its negative regulator, MAP kinase phosphatase-1 (MKP-1), on endothelial cell (EC) injury and early lesion formation using hypercholesterolemic LDLR−/− mice. Methods and results To assess the function of JNK1 in early atherogenesis, we measured EC apoptosis and lesion formation in LDLR−/− or LDLR−/−/JNK1−/− mice exposed to a high fat diet for 6 weeks. En face staining using antibodies that recognise active, cleaved caspase-3 (apoptosis) or using Sudan IV (lipid deposition) revealed that genetic deletion of JNK1 reduced EC apoptosis and lesion formation in hypercholesterolemic mice. By contrast, although EC apoptosis was enhanced in LDLR−/−/MKP-1−/− mice compared to LDLR−/− mice, lesion formation was unaltered. Conclusion We conclude that JNK1 is required for EC apoptosis and lipid deposition during early atherogenesis. Thus pharmacological inhibitors of JNK may reduce atherosclerosis by preventing EC injury as well as by influencing foam cell formation. We studied the role of JNK1 MAP kinase in atherosclerosis. JNK1 was required for endothelial cell apoptosis and lesion formation. An interaction between flow, JNK1 activity and endothelial injury was detected. Targeting of JNK1 may have clinical utility to prevent atherosclerosis.
Collapse
|
64
|
Warboys CM, de Luca A, Amini N, Luong L, Duckles H, Hsiao S, White A, Biswas S, Khamis R, Chong CK, Cheung WM, Sherwin SJ, Bennett MR, Gil J, Mason JC, Haskard DO, Evans PC. Disturbed flow promotes endothelial senescence via a p53-dependent pathway. Arterioscler Thromb Vasc Biol 2014; 34:985-95. [PMID: 24651677 DOI: 10.1161/atvbaha.114.303415] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Although atherosclerosis is associated with systemic risk factors such as age, high cholesterol, and obesity, plaque formation occurs predominately at branches and bends that are exposed to disturbed patterns of blood flow. The molecular mechanisms that link disturbed flow-generated mechanical forces with arterial injury are uncertain. To illuminate them, we investigated the effects of flow on endothelial cell (EC) senescence. APPROACH AND RESULTS LDLR(-/-) (low-density lipoprotein receptor(-/-)) mice were exposed to a high-fat diet for 2 to 12 weeks (or to a normal chow diet as a control) before the assessment of cellular senescence in aortic ECs. En face staining revealed that senescence-associated β-galactosidase activity and p53 expression were elevated in ECs at sites of disturbed flow in response to a high-fat diet. By contrast, ECs exposed to undisturbed flow did not express senescence-associated β-galactosidase or p53. Studies of aortae from healthy pigs (aged 6 months) also revealed enhanced senescence-associated β-galactosidase staining at sites of disturbed flow. These data suggest that senescent ECs accumulate at disturbed flow sites during atherogenesis. We used in vitro flow systems to examine whether a causal relationship exists between flow and EC senescence. Exposure of cultured ECs to flow (using either an orbital shaker or a syringe-pump flow bioreactor) revealed that disturbed flow promoted EC senescence compared with static conditions, whereas undisturbed flow reduced senescence. Gene silencing studies demonstrated that disturbed flow induced EC senescence via a p53-p21 signaling pathway. Disturbed flow-induced senescent ECs exhibited reduced migration compared with nonsenescent ECs in a scratch wound closure assay, and thus may be defective for arterial repair. However, pharmacological activation of sirtuin 1 (using resveratrol or SRT1720) protected ECs from disturbed flow-induced senescence. CONCLUSIONS Disturbed flow promotes endothelial senescence via a p53-p21-dependent pathway which can be inhibited by activation of sirtuin 1. These observations support the principle that pharmacological activation of sirtuin 1 may promote cardiovascular health by suppressing EC senescence at atheroprone sites.
Collapse
|
65
|
Nguyen B, Luong L, Naase H, Vives M, Jakaj G, Finch J, Boyle J, Mulholland JW, Kwak JH, Pyo S, de Luca A, Athanasiou T, Angelini G, Anderson J, Haskard DO, Evans PC. Sulforaphane pretreatment prevents systemic inflammation and renal injury in response to cardiopulmonary bypass. J Thorac Cardiovasc Surg 2014; 148:690-697.e3. [PMID: 24521949 DOI: 10.1016/j.jtcvs.2013.12.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/10/2013] [Accepted: 12/20/2013] [Indexed: 01/23/2023]
Abstract
OBJECTIVES Systemic inflammatory responses are a major cause of morbidity and mortality in patients undergoing cardiac surgery with cardiopulmonary bypass. However, the underlying molecular mechanisms for systemic inflammation in response to cardiopulmonary bypass are poorly understood. METHODS A porcine model was established to study the signaling pathways that promote systemic inflammation in response to cardiac surgery with cardiopulmonary bypass under well-controlled experimental conditions. The influence of sulforaphane, an anti-inflammatory compound derived from green vegetables, on inflammation and injury in response to cardiopulmonary bypass was also studied. Intracellular staining and flow cytometry were performed to measure phosphorylation of p38 mitogen-activated protein kinase and the transcription factor nuclear factor-κB in granulocytes and mononuclear cells. RESULTS Surgery with cardiopulmonary bypass for 1 to 2 hours enhanced phosphorylation of p38 (2.5-fold) and nuclear factor-κB (1.6-fold) in circulating mononuclear cells. Cardiopulmonary bypass also modified granulocytes by activating nuclear factor-κB (1.6-fold), whereas p38 was not altered. Histologic analyses revealed that cardiopulmonary bypass promoted acute tubular necrosis. Pretreatment of animals with sulforaphane reduced p38 (90% reduction) and nuclear factor-κB (50% reduction) phosphorylation in leukocytes and protected kidneys from injury. CONCLUSIONS Systemic inflammatory responses after cardiopulmonary bypass were associated with activation of p38 and nuclear factor-κB pathways in circulating leukocytes. Inflammatory responses to cardiopulmonary bypass can be reduced by sulforaphane, which reduced leukocyte activation and protected against renal injury.
Collapse
|
66
|
Haskard DO, Boyle JJ, Evans PC, Mason JC, Randi AM. Cytoprotective signaling and gene expression in endothelial cells and macrophages-lessons for atherosclerosis. Microcirculation 2013; 20:203-16. [PMID: 23121167 DOI: 10.1111/micc.12020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 10/18/2012] [Indexed: 12/13/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease of the medium and large arteries driven in large part by the accumulation of oxidized low-density lipoproteins and other debris at sites rendered susceptible because of the geometry of the arterial tree. As lesions develop, they acquire a pathologic microcirculation that perpetuates lesion progression, both by providing a means for further monocyte and T-lymphocyte recruitment into the arterial wall and by the physical and chemical stresses caused by micro-hemorrhage. This review summarizes work performed in our department investigating the roles of signaling pathways, alone and in combination, that lead to specific programs of gene expression in the atherosclerotic environment. Focusing particularly on cytoprotective responses that might be enhanced therapeutically, the work has encompassed the anti-inflammatory effects of arterial laminar shear stress, mechanisms of induction of membrane inhibitors that prevent complement-mediated injury, homeostatic macrophage responses to hemorrhage, and the transcriptional mechanisms that control the stability, survival, and quiescence of endothelial monolayers. Lastly, while the field has been dominated by investigation into the mechanisms of DNA transcription, we consider the importance of parallel post-transcriptional regulatory mechanisms for fine-tuning functional gene expression repertoires.
Collapse
|
67
|
|
68
|
Van der Heiden K, Gijsen FJH, Narracott A, Hsiao S, Halliday I, Gunn J, Wentzel JJ, Evans PC. The effects of stenting on shear stress: relevance to endothelial injury and repair. Cardiovasc Res 2013; 99:269-75. [PMID: 23592806 DOI: 10.1093/cvr/cvt090] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Stent deployment following balloon angioplasty is used routinely to treat coronary artery disease. These interventions cause damage and loss of endothelial cells (EC), and thus promote in-stent thrombosis and restenosis. Injured arteries are repaired (intrinsically) by locally derived EC and by circulating endothelial progenitor cells which migrate and proliferate to re-populate denuded regions. However, re-endothelialization is not always complete and often dysfunctional. Moreover, the molecular and biomechanical mechanisms that control EC repair and function in stented segments are poorly understood. Here, we propose that stents modify endothelial repair processes, in part, by altering fluid shear stress, a mechanical force that influences EC migration and proliferation. A more detailed understanding of the biomechanical processes that control endothelial healing would provide a platform for the development of novel therapeutic approaches to minimize damage and promote vascular repair in stented arteries.
Collapse
|
69
|
Luong LA, Fragiadaki M, Smith J, Boyle J, Lutz J, Dean JLE, Harten S, Ashcroft M, Walmsley SR, Haskard DO, Maxwell PH, Walczak H, Pusey C, Evans PC. Cezanne regulates inflammatory responses to hypoxia in endothelial cells by targeting TRAF6 for deubiquitination. Circ Res 2013; 112:1583-91. [PMID: 23564640 DOI: 10.1161/circresaha.111.300119] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
RATIONALE Hypoxia followed by reoxygenation promotes inflammation by activating nuclear factor κB transcription factors in endothelial cells (ECs). This process involves modification of the signaling intermediary tumor necrosis factor receptor-associated factor 6 with polyubiquitin chains. Thus, cellular mechanisms that suppress tumor necrosis factor receptor-associated factor 6 ubiquitination are potential therapeutic targets to reduce inflammation in hypoxic tissues. OBJECTIVE In this study, we tested the hypothesis that endothelial activation in response to hypoxia-reoxygenation can be influenced by Cezanne, a deubiquitinating enzyme that cleaves ubiquitin from specific modified proteins. METHODS AND RESULTS Studies of cultured ECs demonstrated that hypoxia (1% oxygen) induced Cezanne via p38 mitogen-activated protein kinase-dependent transcriptional and post-transcriptional mechanisms. Hypoxia-reoxygenation had minimal effects on proinflammatory signaling in unmanipulated ECs but significantly enhanced Lys63 polyubiquitination of tumor necrosis factor receptor-associated factor 6, activation of nuclear factor κB, and expression of inflammatory genes after silencing of Cezanne. Thus, although hypoxia primed cells for inflammatory activation, it simultaneously induced Cezanne, which impeded signaling to nuclear factor κB by suppressing tumor necrosis factor receptor-associated factor 6 ubiquitination. Similarly, ischemia induced Cezanne in the murine kidney in vascular ECs, glomerular ECs, podocytes, and epithelial cells, and genetic deletion of Cezanne enhanced renal inflammation and injury in murine kidneys exposed to ischemia followed by reperfusion. CONCLUSIONS We conclude that inflammatory responses to ischemia are controlled by a balance between ubiquitination and deubiquitination, and that Cezanne is a key regulator of this process. Our observations have important implications for therapeutic targeting of inflammation and injury during ischemia-reperfusion.
Collapse
|
70
|
Gray C, Bratt D, Lees J, daCosta M, Plant K, Watson OJ, Solaymani-Kohal S, Tazzyman S, Serbanovic-Canic J, Crossman DC, Keavney BD, Haase A, McMahon K, Gering M, Roehl H, Evans PC, Chico TJA. Loss of function of parathyroid hormone receptor 1 induces Notch-dependent aortic defects during zebrafish vascular development. Arterioscler Thromb Vasc Biol 2013; 33:1257-63. [PMID: 23559631 DOI: 10.1161/atvbaha.112.300590] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Coarctation of the aorta is rarely associated with known gene defects. Blomstrand chondrodysplasia, caused by mutations in the parathyroid hormone receptor 1 (PTHR1) is associated with coarctation of the aorta in some cases, although it is unclear whether PTHR1 deficiency causes coarctation of the aorta directly. The zebrafish allows the study of vascular development using approaches not possible in other models. We therefore examined the effect of loss of function of PTHR1 or its ligand parathyroid hormone-related peptide (PTHrP) on aortic formation in zebrafish. APPROACH AND RESULTS Morpholino antisense oligonucleotide knockdown of either PTHR1 or PTHrP led to a localized occlusion of the mid-aorta in developing zebrafish. Confocal imaging of transgenic embryos showed that these defects were caused by loss of endothelium, rather than failure to lumenize. Using a Notch reporter transgenic ([CSL:Venus]qmc61), we found both PTHR1 and PTHrP knockdown-induced defective Notch signaling in the hypochord at the site of the aortic defect before onset of circulation, and the aortic occlusion was rescued by inducible Notch upregulation. CONCLUSIONS Loss of function of either PTHR1 or PTHrP leads to a localized aortic defect that is Notch dependent. These findings may underlie the aortic defect seen in Blomstrand chondrodysplasia, and reveal a link between parathyroid hormone and Notch signaling during aortic development.
Collapse
|
71
|
Boyle JJ, Christou I, Iqbal MB, Nguyen AT, Leung VWY, Evans PC, Liu Y, Johns M, Kirkham P, Haskard DO. Solid-phase immunoglobulins IgG and IgM activate macrophages with solid-phase IgM acting via a novel scavenger receptor a pathway. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:347-61. [PMID: 22658487 DOI: 10.1016/j.ajpath.2012.03.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 02/26/2012] [Accepted: 03/20/2012] [Indexed: 01/21/2023]
Abstract
IgG may accelerate atherosclerosis via ligation of proinflammatory Fcγ receptors; however, IgM is unable to ligate FcγR and is often considered vasculoprotective. IgM aggravates ischemia-reperfusion injury, and solid-phase deposits of pure IgM, as seen with IgM-secreting neoplasms, are well known clinically to provoke vascular inflammation. We therefore examined the molecular mechanisms by which immunoglobulins can aggravate vascular inflammation, such as in atherosclerosis. We compared the ability of fluid- and solid-phase immunoglobulins to activate macrophages. Solid-phase immunoglobulins initiated prothrombotic and proinflammatory functions in human macrophages, including NF-κB p65 activation, H(2)O(2) secretion, macrophage-induced apoptosis, and tissue factor expression. Responses to solid-phase IgG (but not to IgM) were blocked by neutralizing antibodies to CD16 (FcγRIII), consistent with its known role. Macrophages from mice deficient in macrophage scavenger receptor A (SR-A; CD204) had absent IgM binding and no activation by solid-phase IgM. RNA interference-mediated knockdown of SR-A in human macrophages suppressed activation by solid-phase IgM. IgM binding to SR-A was demonstrated by both co-immunoprecipitation studies and the binding of fluorescently labeled IgM to SR-A-transfected cells. Immunoglobulins on solid-phase particles around macrophages were found in human plaques, increased in ruptured plaques compared with stable ones. These observations indicate that solid-phase IgM and IgG can activate macrophages and destabilize vulnerable plaques. Solid-phase IgM activates macrophages via a novel SR-A pathway.
Collapse
|
72
|
Pfenniger A, Wong C, Sutter E, Cuhlmann S, Dunoyer-Geindre S, Mach F, Horrevoets AJ, Evans PC, Krams R, Kwak BR. Shear stress modulates the expression of the atheroprotective protein Cx37 in endothelial cells. J Mol Cell Cardiol 2012; 53:299-309. [PMID: 22659288 DOI: 10.1016/j.yjmcc.2012.05.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 05/19/2012] [Indexed: 12/28/2022]
Abstract
High laminar shear stress (HLSS) is vasculoprotective partly through induction of Kruppel-like factor 2 (KLF2). Connexin37 (Cx37) is highly expressed in endothelial cells (ECs) of healthy arteries, but not in ECs overlying atherosclerotic lesions. Moreover, Cx37 deletion in apolipoprotein E-deficient (ApoE(-/-)) mice increases susceptibility to atherosclerosis. We hypothesized that shear stress, through KLF2 modulation, may affect Cx37 expression in ECs. Cx37 expression and gap-junctional intercellular (GJIC) dye transfer are prominent in the straight portion of carotid arteries of ApoE(-/-) mice, but are reduced at the carotid bifurcation, a region subjected to oscillatory flow. Shear stress-modifying vascular casts were placed around the common carotid artery of ApoE(-/-) mice. Whereas Cx37 expression was conserved in HLSS regions, it was downregulated to ~50% in low laminar or oscillatory flow regions. To study the mechanisms involved, HUVECs or bEnd.3 cells were exposed to flow in vitro. Cx37 and KLF2 expression were increased after 24h of HLSS. Interestingly, shear-dependent Cx37 expression was significantly reduced after silencing of KLF2. Moreover after exposure to simvastatin, a well-known KLF2 inducer, KLF2 binds to the Cx37 promoter region as shown by ChIP. Finally, GJIC dye transfer was highly reduced after KLF2 silencing and was increased after exposure to simvastatin. HLSS upregulates the expression of Cx37 in ECs by inducing its transcription factor KLF2, which increases intercellular communication. Therefore, this effect of shear stress on Cx37 expression may contribute to the synchronization of ECs and participate in the protective effect of HLSS.
Collapse
|
73
|
Boyle JJ, Johns M, Lo J, Chiodini A, Ambrose N, Evans PC, Mason JC, Haskard DO. Heme induces heme oxygenase 1 via Nrf2: role in the homeostatic macrophage response to intraplaque hemorrhage. Arterioscler Thromb Vasc Biol 2012; 31:2685-91. [PMID: 21868703 DOI: 10.1161/atvbaha.111.225813] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Intraplaque hemorrhage (IPH) is an important progression event in advanced atherosclerosis, in large part because of the delivery of prooxidant hemoglobin in erythrocytes. We have previously defined a novel macrophage phenotype (hemorrhage-associated-mac) in human advanced plaques with IPH. These may be atheroprotective in view of raised heme oxygenase 1 (HO-1), CD163, and interleukin-10 expression and suppressed oxidative stress. METHODS AND RESULTS We have used a combination of small interfering RNA and pharmacological reagents, protein analysis, and oxidative stress measurements to dissect the pathway leading to the development of this phenotype. We found that erythrocytes, hemoglobin, or purified heme similarly induced CD163 and suppressed human leukocyte antigen and reactive oxygen species. HO-1 was required for the development of each of these features. Challenge of macrophages with purified heme provoked nuclear translocation of Nrf2, and Nrf2 small interfering RNA resulted in significant inhibition of the ability of heme to induce HO-1 protein. Furthermore, tert-butyl-hydroquinone, which activates Nrf2, upregulated CD163, suppressed human leukocyte antigen, and induced interleukin-10, further supporting a role for Nrf2-mediated signaling. However, an inducible protein transactivator is also probably necessary, as heme-induced HO-1 mRNA expression was fully inhibited by the protein synthesis inhibitor cycloheximide. CONCLUSION Our experiments define an Nrf2-mediated pathway by which heme induces a homeostatic macrophage response following IPH.
Collapse
|
74
|
Kuhlmann MT, Cuhlmann S, Hoppe I, Krams R, Evans PC, Strijkers GJ, Nicolay K, Hermann S, Schäfers M. Implantation of a carotid cuff for triggering shear-stress induced atherosclerosis in mice. J Vis Exp 2012:3308. [PMID: 22294044 DOI: 10.3791/3308] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
It is widely accepted that alterations in vascular shear stress trigger the expression of inflammatory genes in endothelial cells and thereby induce atherosclerosis (reviewed in (1) and (2)). The role of shear stress has been extensively studied in vitro investigating the influence of flow dynamics on cultured endothelial cells and in vivo in larger animals and humans. However, highly reproducible small animal models allowing systematic investigation of the influence of shear stress on plaque development are rare. Recently, Nam et al. introduced a mouse model in which the ligation of branches of the carotid artery creates a region of low and oscillatory flow. Although this model causes endothelial dysfunction and rapid formation of atherosclerotic lesions in hyperlipidemic mice, it cannot be excluded that the observed inflammatory response is, at least in part, a consequence of endothelial and/or vessel damage due to ligation. In order to avoid such limitations, a shear stress modifying cuff has been developed based upon calculated fluid dynamics, whose cone shaped inner lumen was selected to create defined regions of low, high and oscillatory shear stress within the common carotid artery. By applying this model in Apolipoprotein E (ApoE) knockout mice fed a high cholesterol western type diet, vascular lesions develop upstream and downstream from the cuff. Their phenotype is correlated with the regional flow dynamics as confirmed by in vivo Magnetic Resonance Imaging (MRI): Low and laminar shear stress upstream of the cuff causes the formation of extensive plaques of a more vulnerable phenotype, whereas oscillatory shear stress downstream of the cuff induces stable atherosclerotic lesions. In those regions of high shear stress and high laminar flow within the cuff, typically no atherosclerotic plaques are observed. In conclusion, the shear stress-modifying cuff procedure is a reliable surgical approach to produce phenotypically different atherosclerotic lesions in ApoE-deficient mice.
Collapse
|
75
|
Luong LA, Evans PC. Targeting inhibitor of apoptosis proteins to block vascular inflammation. Arterioscler Thromb Vasc Biol 2011; 31:2165-6. [PMID: 21918207 DOI: 10.1161/atvbaha.111.235762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
76
|
Jevon M, Ansari TI, Finch J, Zakkar M, Evans PC, Shurey S, Sibbons PD, Hornick P, Haskard DO, Dorling A. Smooth muscle cells in porcine vein graft intimal hyperplasia are derived from the local vessel wall. Cardiovasc Pathol 2011; 20:e91-4. [PMID: 20537564 DOI: 10.1016/j.carpath.2010.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 04/06/2010] [Accepted: 04/19/2010] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Accelerated intimal hyperplasia (IH) is an important cause of morbidity and mortality in patients with atherosclerotic vascular disease treated with bypass vein grafts. We used an interposition vein graft model to determine the source of neointimal cells in a clinically relevant large animal model. METHODS Jugular vein segments from sex-mismatched, MHC-in-bred pigs were implanted into common carotid arteries bilaterally and harvested up to 8 weeks postsurgery for stereological, histological, and immunofluorescence analyses. RESULTS Progressive IH lesions contained macrophages and smooth muscle cells (SMC). Fluorescent in situ hybridization following grafting of female veins into male arteries revealed that only ∼10% of the SMC were male, confirming that the majority of intimal SMC derived from the local vessel wall. CONCLUSIONS The majority of neointimal SMC in the IH seen after interposition vein grafting derive from the engrafted local vessel wall. These are the first results from a clinically relevant large animal model that confirm data from rodent models. They have implications for the utility of therapeutic stem cells in this type of intimal hyperplasia.
Collapse
|
77
|
Warboys CM, Amini N, de Luca A, Evans PC. The role of blood flow in determining the sites of atherosclerotic plaques. F1000 MEDICINE REPORTS 2011; 3:5. [PMID: 21654925 PMCID: PMC3096883 DOI: 10.3410/m3-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids and inflammatory cells along the inner walls of arteries, and is an underlying cause of cardiovascular disease. Atherosclerotic lesions develop predominantly at branches, bends, and bifurcations in the arterial tree because these sites are exposed to low or disturbed blood flow, which exerts low/oscillatory shear stress on the vessel wall. This mechanical environment alters endothelial cell physiology by enhancing inflammatory activation. In contrast, regions of the arterial tree that are exposed to uniform, unidirectional blood flow and experience high shear stress are protected from inflammation and lesion development. Shear stress is sensed by the endothelium via mechanoreceptors and is subsequently transduced into biochemical signals resulting in modulation of proinflammatory signaling pathways. In this article, we address the molecular mechanisms behind the spatial localization of vascular inflammation and atherosclerosis, with particular focus on studies by our own group of two key proinflammatory signaling pathways, the mitogen-activated protein kinase pathway and the nuclear factor-kappa-B pathway.
Collapse
|
78
|
Cuhlmann S, Van der Heiden K, Saliba D, Tremoleda JL, Khalil M, Zakkar M, Chaudhury H, Luong LA, Mason JC, Udalova I, Gsell W, Jones H, Haskard DO, Krams R, Evans PC. Disturbed blood flow induces RelA expression via c-Jun N-terminal kinase 1: a novel mode of NF-κB regulation that promotes arterial inflammation. Circ Res 2011; 108:950-9. [PMID: 21350211 DOI: 10.1161/circresaha.110.233841] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
RATIONALE The nuclear factor (NF)-κB pathway is involved in arterial inflammation. Although the signaling pathways that regulate transcriptional activation of NF-κB are defined, the mechanisms that regulate the expression levels of NF-κB transcription factors are uncertain. OBJECTIVE We studied the signaling mechanisms that regulate RelA NF-κB subunit expression in endothelial cells (ECs) and their role in arterial inflammation. METHODS AND RESULTS Gene silencing and chromatin immunoprecipitation revealed that RelA expression was positively regulated by c-Jun N-terminal kinase (JNK) and the downstream transcription factor ATF2 in ECs. We concluded that this pathway promotes focal arterial inflammation as genetic deletion of JNK1 reduced NF-κB expression and macrophage accumulation at an atherosusceptible site. We hypothesized that JNK signaling to NF-κB may be controlled by mechanical forces because atherosusceptibility is associated with exposure to disturbed blood flow. This was assessed by positron emission tomography imaging of carotid arteries modified with a constrictive cuff, a method that was developed to study the effects of disturbed flow on vascular physiology in vivo. This approach coupled to en face staining revealed that disturbed flow elevates NF-κB expression and inflammation in murine carotid arteries via JNK1. CONCLUSIONS We demonstrate that disturbed blood flow promotes arterial inflammation by inducing NF-κB expression in endothelial cells via JNK-ATF2 signaling. Thus, our findings illuminate a novel form of JNK-NF-κB crosstalk that may determine the focal nature of arterial inflammation and atherosclerosis.
Collapse
|
79
|
Evans PC. The influence of sulforaphane on vascular health and its relevance to nutritional approaches to prevent cardiovascular disease. EPMA J 2011. [PMID: 23199123 PMCID: PMC3405367 DOI: 10.1007/s13167-011-0064-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Oxidation of low-density lipoproteins (LDL) promotes atherosclerosis by enhancing vascular inflammation and foam cell formation. The corollary is that diets that stimulate endogenous anti-oxidants may protect against atherosclerosis. This review focuses on sulforaphane, an isothiocyanate derived from green vegetables, which induces multiple anti-oxidant enzymes via activation of a transcription factor called Nrf2. Although studies of cultured cells and experimental animals revealed that sulforaphane can suppress inflammatory activation of vascular cells, the potential beneficial effects of sulforaphane in atherosclerosis have not been studied directly. A deeper understanding of vascular responses to sulforaphane may inform nutritional approaches to prevent vascular inflammation and atherosclerosis.
Collapse
|
80
|
Zakkar M, Luong LA, Chaudhury H, Ruud O, Punjabi PP, Anderson JR, Mullholand JW, Clements AT, Krams R, Foin N, Athanasiou T, Leen ELS, Mason JC, Haskard DO, Evans PC. Dexamethasone arterializes venous endothelial cells by inducing mitogen-activated protein kinase phosphatase-1: a novel antiinflammatory treatment for vein grafts? Circulation 2011; 123:524-32. [PMID: 21262999 DOI: 10.1161/circulationaha.110.979542] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Vein grafting in coronary artery surgery is complicated by a high restenosis rate resulting from the development of vascular inflammation, intimal hyperplasia, and accelerated atherosclerosis. In contrast, arterial grafts are relatively resistant to these processes. Vascular inflammation is regulated by signaling intermediaries, including p38 mitogen-activated protein (MAP) kinase, that trigger endothelial cell (EC) expression of chemokines (eg, interleukin-8, monocyte chemotactic protein-1) and other proinflammatory molecules. Here, we have tested the hypothesis that p38 MAP kinase activation in response to arterial shear stress (flow) may occur more readily in venous ECs, leading to greater proinflammatory activation. METHODS AND RESULTS Comparative reverse-transcriptase polymerase chain reaction and Western blotting revealed that arterial shear stress induced p38-dependent expression of monocyte chemotactic protein-1 and interleukin-8 in porcine jugular vein ECs. In contrast, porcine aortic ECs were protected from shear stress-induced expression of p38-dependent chemokines as a result of rapid induction of MAP kinase phosphatase-1. However, we observed with both cultured porcine jugular vein ECs and perfused veins that venous ECs can be protected by brief treatment with dexamethasone, which induced MAP kinase phosphatase-1 to suppress proinflammatory activation. CONCLUSIONS Arterial but not venous ECs are protected from proinflammatory activation in response to short-term exposure to high shear stress by the induction of MAP kinase phosphatase-1. Dexamethasone pretreatment arterializes venous ECs by inducing MAP kinase phosphatase-1 and may protect veins from inflammation.
Collapse
|
81
|
Sperone A, Dryden NH, Birdsey GM, Madden L, Johns M, Evans PC, Mason JC, Haskard DO, Boyle JJ, Paleolog EM, Randi AM. The transcription factor Erg inhibits vascular inflammation by repressing NF-kappaB activation and proinflammatory gene expression in endothelial cells. Arterioscler Thromb Vasc Biol 2010; 31:142-50. [PMID: 20966395 DOI: 10.1161/atvbaha.110.216473] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To test whether ETS-related gene (Erg) inhibits tumor necrosis factor (TNF)-α-dependent endothelial activation and inflammation. METHODS AND RESULTS Endothelial activation underlies many vascular diseases, including atherosclerosis. Endothelial activation by proinflammatory cytokines decreases expression of the ETS transcription factor Erg. By using human umbilical vein endothelial cells (HUVECs), we showed that Erg overexpression by adenovirus (AdErg) repressed basal and TNF-α-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM), and interleukin 8 (IL-8). Erg inhibited TNF-α-dependent activation of the ICAM-1 promoter, nuclear factor (NF)-κB activity, and NF-κB p65 phosphorylation. Basal NF-κB activity was also inhibited by Erg overexpression. Chromatin immunoprecipitation showed that Erg binds to the ICAM-1 proximal promoter region, which contains 7 putative ETS binding sites. To test the anti-inflammatory role of Erg in vivo, we used a murine model of TNF-α-dependent acute inflammation. The injection of AdErg into the paw decreased TNF-α-induced inflammation compared with control. Finally, staining of human coronary plaques showed loss of Erg expression from the endothelium overlaying active plaque shoulders. CONCLUSIONS We have identified a novel physiological anti-inflammatory pathway under the control of the transcription factor Erg; this pathway inhibits NF-κB-dependent transcription and TNF-α-induced inflammation in vivo. These results suggest a novel approach to anti-inflammatory therapies.
Collapse
|
82
|
Vossenkämper A, Marchès O, Fairclough PD, Warnes G, Stagg AJ, Lindsay JO, Evans PC, Luong LA, Croft NM, Naik S, Frankel G, MacDonald TT. Inhibition of NF-κB signaling in human dendritic cells by the enteropathogenic Escherichia coli effector protein NleE. THE JOURNAL OF IMMUNOLOGY 2010; 185:4118-27. [PMID: 20833837 DOI: 10.4049/jimmunol.1000500] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intestinal dendritic cells (DCs) send processes between epithelial cells into the gut lumen to sample pathogens. Noninvasive enteropathogenic Escherichia coli (EPEC) colonize the gut using a type three secretion system (T3SS) to inject effector proteins into epithelial cells. We hypothesized that EPEC might also inject proteins into DC processes to dampen immune recognition. Using a T3SS-linked fluorescence resonance energy transfer-based system we show that EPEC injects effectors into in vitro grown human myeloid DCs. Injected cells emit a blue signal due to cleavage of the green fluorescence resonance energy transfer-based substrate CCF2/AM by β-lactamase. When cultured with a mutant EPEC unable to translocate effector proteins, myeloid DCs show rapid activation of NF-κB, secrete large amounts of proinflammatory cytokines and increase expression of CD80, CD83, and CD86, whereas wild-type EPEC barely elicits cytokine production and shuts off nuclear translocation of NF-κB p65. By deleting effector protein genes, we identified NleE as being critical for this effect. Expression of NleE in HeLa cells completely prevented nuclear p65 accumulation in response to IL1-β, and luciferase production in an NF-κB reporter cell line. DCs cocultured with wild-type EPEC or NleE-complemented strains were less potent at inducing MLR. EPEC was also able to inject effectors into DCs sending processes through model gut epithelium in a transwell system and into Peyer's patch myeloid DCs. Thus, EPEC translocate effectors into human DCs to dampen the inflammatory response elicited by its own pathogen-associated molecular patterns.
Collapse
|
83
|
Hummel J, Evans PC, Lee H. Medication reconciliation in the emergency department: opportunities for workflow redesign. Qual Saf Health Care 2010; 19:531-5. [PMID: 20554575 DOI: 10.1136/qshc.2009.035121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To examine the role of workflow redesign to improve medication reconciliation at four Washington State community hospital emergency departments. METHOD Lean redesign methodology was used for workflow process mapping and redesign workshops attended by emergency department staff. Observations were made about barriers to successful operation of current medication reconciliation workflows, and ideal future process maps were developed to improve the efficacy of creating a current, complete and accurate medication list for each patient seen in the emergency department. CONCLUSION Ideas for an optimal workflow to generate a medication list include involving patients and utilising clerical staff to a greater extent in medication information gathering, identifying and flagging patients with missing medication information, and gathering only the medication information needed to make clinical decisions in the emergency department.
Collapse
|
84
|
Hamdulay SS, Wang B, Birdsey GM, Ali F, Dumont O, Evans PC, Haskard DO, Wheeler-Jones CP, Mason JC. Celecoxib activates PI-3K/Akt and mitochondrial redox signaling to enhance heme oxygenase-1-mediated anti-inflammatory activity in vascular endothelium. Free Radic Biol Med 2010; 48:1013-23. [PMID: 20083195 DOI: 10.1016/j.freeradbiomed.2010.01.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 12/11/2009] [Accepted: 01/09/2010] [Indexed: 11/19/2022]
Abstract
Although nonsteroidal anti-inflammatory drugs (NSAIDs) provide important control of pain and inflammation, they have been overshadowed by concerns regarding atherothrombotic complications. However, celecoxib seems to have a relatively good cardiovascular profile and may improve endothelial function in coronary heart disease. This led us to the hypothesis that celecoxib induces the vasculoprotective enzyme heme oxygenase-1 (HO-1). In human umbilical vein and aortic endothelial cells, 24-48 h treatment with celecoxib induced HO-1 mRNA and protein expression and increased HO-1 enzyme activity. This effect was not seen with rofecoxib or indomethacin. Supplementation of culture medium with iloprost or prostaglandin E(2) failed to reverse celecoxib-mediated HO-1 induction, indicating a cyclooxygenase-independent mechanism. Rather, this action of celecoxib involved generation of mitochondria-derived reactive oxygen species, Akt phosphorylation, and nuclear translocation of the transcription factor Nrf2, with N-acetylcysteine, PI-3K antagonist LY290042, and dominant-negative Akt abrogating the effects. Furthermore, celecoxib-induced HO-1 was inhibited by dominant-negative Nrf2. The functional significance of HO-1 induction was revealed by celecoxib-mediated inhibition of VCAM-1 expression, a response reversed by the HO-1 antagonist zinc protoporphyrin. HO-1 induction provides a molecular mechanism for clinical observations indicating relative freedom from atherothrombotic complications in patients taking celecoxib compared to other NSAIDs with comparable anti-inflammatory activity.
Collapse
|
85
|
Chaudhury H, Zakkar M, Boyle J, Cuhlmann S, van der Heiden K, Luong LA, Davis J, Platt A, Mason JC, Krams R, Haskard DO, Clark AR, Evans PC. c-Jun N-Terminal Kinase Primes Endothelial Cells at Atheroprone Sites for Apoptosis. Arterioscler Thromb Vasc Biol 2010; 30:546-53. [DOI: 10.1161/atvbaha.109.201368] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Objective—
Atherosclerosis is a focal disease that occurs predominantly at branches and bends of the arterial tree. Endothelial cells (EC) at atherosusceptible sites are prone to injury, which can contribute to lesion formation, whereas EC at atheroprotected sites are resistant. The c-Jun N-terminal kinase (JNK) is activated constitutively in EC at atherosusceptible sites but is inactivated at atheroprotected sites by mitogen-activated protein kinase phosphatase-1 (MKP-1). Here, we examined the effects of JNK activation on EC physiology at atherosusceptible sites.
Methods and Results—
We identified transcriptional programs regulated by JNK by applying a specific pharmacological inhibitor to cultured EC and assessing the transcriptome using microarrays. This approach and subsequent validation by gene silencing revealed that JNK positively regulates the expression of numerous proapoptotic molecules. Analysis of aortae of wild-type, JNK1
−/−
, and MKP-1
−/−
mice revealed that EC at an atherosusceptible site express proapoptotic proteins and are primed for apoptosis and proliferation in response to lipopolysaccharide through a JNK1-dependent mechanism, whereas EC at a protected site expressed lower levels of proapoptotic molecules and were protected from injury by MKP-1.
Conclusion—
Spatial variation of JNK1 activity delineates the spatial distribution of apoptosis and turnover of EC in arteries.
Collapse
|
86
|
Amirak E, Zakkar M, Evans PC, Kemp PR. Perfusion of veins at arterial pressure increases the expression of KLF5 and cell cycle genes in smooth muscle cells. Biochem Biophys Res Commun 2009; 391:818-23. [PMID: 19958749 PMCID: PMC2824850 DOI: 10.1016/j.bbrc.2009.11.145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 11/21/2009] [Indexed: 01/14/2023]
Abstract
Vascular smooth muscle cell (VSMC) proliferation remains a major cause of veno-arterial graft failure. We hypothesised that exposure of venous SMCs to arterial pressure would increase KLF5 expression and that of cell cycle genes. Porcine jugular veins were perfused at arterial or venous pressure in the absence of growth factors. The KLF5, c-myc, cyclin-D and cyclin-E expression were elevated within 24h of perfusion at arterial pressure but not at venous pressure. Arterial pressure also reduced the decline in SM-myosin heavy chain expression. These data suggest a role for KLF5 in initiating venous SMCs proliferation in response to arterial pressure.
Collapse
|
87
|
Zakkar M, Van der Heiden K, Luong LA, Chaudhury H, Cuhlmann S, Hamdulay SS, Krams R, Edirisinghe I, Rahman I, Carlsen H, Haskard DO, Mason JC, Evans PC. Activation of Nrf2 in endothelial cells protects arteries from exhibiting a proinflammatory state. Arterioscler Thromb Vasc Biol 2009; 29:1851-7. [PMID: 19729611 DOI: 10.1161/atvbaha.109.193375] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Proinflammatory mediators influence atherosclerosis by inducing adhesion molecules (eg, VCAM-1) on endothelial cells (ECs) via signaling intermediaries including p38 MAP kinase. Regions of arteries exposed to high shear stress are protected from inflammation and atherosclerosis, whereas low-shear regions are susceptible. Here we investigated whether the transcription factor Nrf2 regulates EC activation in arteries. METHODS AND RESULTS En face staining revealed that Nrf2 was activated in ECs at an atheroprotected region of the murine aorta where it negatively regulated p38-VCAM-1 signaling, but was expressed in an inactive form in ECs at an atherosusceptible site. Treatment with sulforaphane, a dietary antioxidant, activated Nrf2 and suppressed p38-VCAM-1 signaling at the susceptible site in wild-type but not Nrf2(-/-) animals, indicating that it suppresses EC activation via Nrf2. Studies of cultured ECs revealed that Nrf2 inactivates p38 by suppressing an upstream activator MKK3/6 and by enhancing the activity of the negative regulator MKP-1. CONCLUSIONS Nrf2 prevents ECs at the atheroprotected site from exhibiting a proinflammatory state via the suppression of p38-VCAM-1 signaling. Pharmacological activation of Nrf2 reduces EC activation at atherosusceptible sites and may provide a novel therapeutic strategy to prevent or reduce atherosclerosis.
Collapse
|
88
|
Ali F, Zakkar M, Karu K, Lidington EA, Hamdulay SS, Boyle JJ, Zloh M, Bauer A, Haskard DO, Evans PC, Mason JC. Induction of the cytoprotective enzyme heme oxygenase-1 by statins is enhanced in vascular endothelium exposed to laminar shear stress and impaired by disturbed flow. J Biol Chem 2009; 284:18882-92. [PMID: 19457866 PMCID: PMC2707208 DOI: 10.1074/jbc.m109.009886] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Indexed: 12/11/2022] Open
Abstract
In addition to cholesterol-lowering properties, statins exhibit lipid-independent immunomodulatory, anti-inflammatory actions. However, high concentrations are typically required to induce these effects in vitro, raising questions concerning therapeutic relevance. We present evidence that endothelial cell sensitivity to statins depends upon shear stress. Using heme oxygenase-1 expression as a model, we demonstrate differential heme oxygenase-1 induction by atorvastatin in atheroresistant compared with atheroprone sites of the murine aorta. In vitro, exposure of human endothelial cells to laminar shear stress significantly reduced the statin concentration required to induce heme oxygenase-1 and protect against H(2)O(2)-mediated injury. Synergy was observed between laminar shear stress and atorvastatin, resulting in optimal expression of heme oxygenase-1 and resistance to oxidative stress, a response inhibited by heme oxygenase-1 small interfering RNA. Moreover, treatment of laminar shear stress-exposed endothelial cells resulted in a significant fall in intracellular cholesterol. Mechanistically, synergy required Akt phosphorylation, activation of Kruppel-like factor 2, NF-E2-related factor-2 (Nrf2), increased nitric-oxide synthase activity, and enhanced HO-1 mRNA stability. In contrast, heme oxygenase-1 induction by atorvastatin in endothelial cells exposed to oscillatory flow was markedly attenuated. We have identified a novel relationship between laminar shear stress and statins, demonstrating that atorvastatin-mediated heme oxygenase-1-dependent antioxidant effects are laminar shear stress-dependent, proving the principle that biomechanical signaling contributes significantly to endothelial responsiveness to pharmacological agents. Our findings suggest statin pleiotropy may be suboptimal at disturbed flow atherosusceptible sites, emphasizing the need for more specific therapeutic agents, such as those targeting Kruppel-like factor 2 or Nrf2.
Collapse
|
89
|
|
90
|
Evans PC. Effects of shear stress on endothelial activation and vascular inflammation. Pharmacotherapy 2008. [DOI: 10.1016/j.biopha.2008.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
91
|
Zakkar M, Chaudhury H, Sandvik G, Enesa K, Luong LA, Cuhlmann S, Mason JC, Krams R, Clark AR, Haskard DO, Evans PC. Increased Endothelial Mitogen-Activated Protein Kinase Phosphatase-1 Expression Suppresses Proinflammatory Activation at Sites That Are Resistant to Atherosclerosis. Circ Res 2008; 103:726-32. [DOI: 10.1161/circresaha.108.183913] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease of arteries. It is triggered by proinflammatory mediators which induce adhesion molecules (eg, vascular cell adhesion molecule [VCAM]-1) in endothelial cells (ECs) by activating p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinases by phosphorylation. Blood flow influences atherosclerosis by exerting shear stress (mechanical drag) on the inner surface of arteries, a force that alters endothelial physiology. Regions of the arterial tree exposed to high shear are protected from endothelial activation, inflammation, and atherosclerosis, whereas regions exposed to low or oscillatory shear are susceptible. We examined whether MAP kinase phosphatase (MKP)-1, a negative regulator of p38 and JNK, mediates the antiinflammatory effects of shear stress. We observed that expression of MKP-1 in cultured ECs was elevated by shear stress, whereas the expression of VCAM-1 was reduced. MKP-1 induction was shown to be necessary for the antiinflammatory effects of shear stress because gene silencing of MKP-1 restored VCAM-1 expression in sheared ECs. Immunostaining revealed that MKP-1 is preferentially expressed by ECs in a high-shear, protected region of the mouse aorta and is necessary for suppression of EC activation at this site, because p38 activation and VCAM-1 expression was enhanced by genetic deletion of MKP-1. We conclude that MKP-1 induction is required for the antiinflammatory effects of shear stress. Thus, our findings reveal a novel molecular mechanism contributing to the spatial distribution of vascular inflammation and atherosclerosis.
Collapse
|
92
|
Ridger V, Krams R, Carpi A, Evans PC. Hemodynamic parameters regulating vascular inflammation and atherosclerosis: a brief update. Biomed Pharmacother 2008; 62:536-40. [PMID: 18757166 DOI: 10.1016/j.biopha.2008.07.053] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 07/01/2008] [Indexed: 12/21/2022] Open
Abstract
Atherosclerosis is a chronic lipid-driven inflammatory disease of the arteries. Early lesions (fatty streaks) contain monocytes and T lymphocytes which are recruited from the circulation by adhesion to activated vascular endothelial cells (EC). This process is described as the leukocyte adhesion cascade. Atherogenesis occurs predominantly at branches and bends of the arterial tree that are exposed to relatively low or re-circulating blood flow. Here we briefly review the effects of blood flow and shear stress on the leukocyte adhesion cascade and endothelial cell function.
Collapse
|
93
|
Enesa K, Ito K, Luong LA, Thorbjornsen I, Phua C, To Y, Dean J, Haskard DO, Boyle J, Adcock I, Evans PC. Hydrogen Peroxide Prolongs Nuclear Localization of NF-κB in Activated Cells by Suppressing Negative Regulatory Mechanisms. J Biol Chem 2008; 283:18582-90. [DOI: 10.1074/jbc.m801312200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
94
|
Birks EJ, Latif N, Enesa K, Folkvang T, Luong LA, Sarathchandra P, Khan M, Ovaa H, Terracciano CM, Barton PJR, Yacoub MH, Evans PC. Elevated p53 expression is associated with dysregulation of the ubiquitin-proteasome system in dilated cardiomyopathy. Cardiovasc Res 2008; 79:472-80. [PMID: 18375498 DOI: 10.1093/cvr/cvn083] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The molecular mechanisms that regulate cardiomyocyte apoptosis and their role in human heart failure (HF) are uncertain. Expression of the apoptosis regulator p53 is governed by minute double minute 2 (MDM2), an E3 enzyme that targets p53 for ubiquitination and proteasomal processing, and by the deubiquitinating enzyme, herpesvirus-associated ubiquitin-specific protease (HAUSP), which rescues p53 by removing ubiquitin chains from it. Here, we examined whether elevated expression of p53 was associated with dysregulation of ubiquitin-proteasome system (UPS) components and activation of downstream effectors of apoptosis in human dilated cardiomyopathy (DCM). METHODS AND RESULTS Left ventricular myocardial samples were obtained from patients with DCM (n = 12) or from non-failing (donor) hearts (n = 17). Western blotting and immunohistochemistry revealed that DCM tissues contained elevated levels of p53 and its regulators MDM2 and HAUSP (all P < 0.01) compared with non-failing hearts. DCM tissues also contained elevated levels of polyubiquitinated proteins and possessed enhanced 20S-proteasome chymotrypsin-like activities (P < 0.04) as measured in vitro using a fluorogenic substrate. DCM tissues contained activated caspases-9 and -3 (P < 0.001) and reduced expression of the caspase substrate PARP-1 (P < 0.05). Western blotting and immunohistochemistry revealed that DCM tissues contained elevated expression levels of caspase-3-activated DNAse (CAD; P < 0.001), which is a key effector of DNA fragmentation in apoptosis and also contained elevated expression of a potent inhibitor of CAD (ICAD-S; P < 0.01). CONCLUSION Expression of p53 in human DCM is associated with dysregulation of UPS components, which are known to regulate p53 stability. Elevated p53 expression and caspase activation in DCM was not associated with activation of both CAD and its inhibitor, ICAD-S. Our findings are consistent with the concept that apoptosis may be interrupted and therefore potentially reversible in human HF.
Collapse
|
95
|
Kinderlerer AR, Ali F, Johns M, Lidington EA, Leung V, Boyle JJ, Hamdulay SS, Evans PC, Haskard DO, Mason JC. KLF2-dependent, shear stress-induced expression of CD59: a novel cytoprotective mechanism against complement-mediated injury in the vasculature. J Biol Chem 2008; 283:14636-44. [PMID: 18362151 DOI: 10.1074/jbc.m800362200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Complement activation may predispose to vascular injury and atherogenesis. The atheroprotective actions of unidirectional laminar shear stress led us to explore its influence on endothelial cell expression of complement inhibitory proteins CD59 and decay-accelerating factor. Human umbilical vein and aortic endothelial cells were exposed to laminar shear stress (12 dynes/cm(2)) or disturbed flow (+/- 5 dynes/cm(2) at 1Hz) in a parallel plate flow chamber. Laminar shear induced a flow rate-dependent increase in steady-state CD59 mRNA, reaching 4-fold at 12 dynes/cm(2). Following 24-48 h of laminar shear stress, cell surface expression of CD59 was up-regulated by 100%, whereas decay-accelerating factor expression was unchanged. The increase in CD59 following laminar shear was functionally significant, reducing C9 deposition and complement-mediated lysis of flow-conditioned endothelial cells by 50%. Although CD59 induction was independent of PI3-K, ERK1/2 and nitric oxide, an RNA interference approach demonstrated dependence upon an ERK5/KLF2 signaling pathway. In contrast to laminar shear stress, disturbed flow failed to induce endothelial cell CD59 protein expression. Likewise, CD59 expression on vascular endothelium was significantly higher in atheroresistant regions of the murine aorta exposed to unidirectional laminar shear stress, when compared with atheroprone areas exposed to disturbed flow. We propose that up-regulation of CD59 via ERK5/KLF2 activation leads to endothelial resistance to complement-mediated injury and protects from atherogenesis in regions of laminar shear stress.
Collapse
|
96
|
Enesa K, Zakkar M, Chaudhury H, Luong LA, Rawlinson L, Mason JC, Haskard DO, Dean JLE, Evans PC. NF-kappaB suppression by the deubiquitinating enzyme Cezanne: a novel negative feedback loop in pro-inflammatory signaling. J Biol Chem 2008; 283:7036-45. [PMID: 18178551 DOI: 10.1074/jbc.m708690200] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transcription factors belonging to the NF-kappaB family regulate inflammation by inducing pro-inflammatory molecules (e.g. interleukin (IL)-8) in response to cytokines (e.g. tumor necrosis factor (TNF) alpha, IL-1) or other stimuli. Several negative regulators of NF-kappaB, including the ubiquitin-editing enzyme A20, participate in the resolution of inflammatory responses. We report that Cezanne, a member of the A20 family of the deubiquitinating cysteine proteases, can be induced by TNFalpha in cultured cells. Silencing of endogenous Cezanne using small interfering RNA led to elevated NF-kappaB luciferase reporter gene activity and enhanced expression of IL-8 transcripts in TNFalpha-treated cells. Thus we conclude that endogenous Cezanne can attenuate NF-kappaB activation and the induction of pro-inflammatory transcripts in response to TNF receptor (TNFR) signaling. Overexpression studies revealed that Cezanne suppressed NF-kappaB nuclear translocation and transcriptional activity by targeting the TNFR signaling pathway at the level of the IkappaB kinase complex or upstream from it. These effects were not observed in a form of Cezanne that was mutated at the catalytic cysteine residue (Cys209), indicating that the deubiquitinating activity of Cezanne is essential for NF-kappaB regulation. Finally, we demonstrate that Cezanne can be recruited to activated TNFRs where it suppresses the build-up of polyubiquitinated RIP1 signal adapter proteins. Thus we conclude that Cezanne forms a novel negative feedback loop in pro-inflammatory signaling and that it suppresses NF-kappaB activation by targeting RIP1 signaling intermediaries for deubiquitination.
Collapse
|
97
|
Helderman F, Segers D, de Crom R, Hierck BP, Poelmann RE, Evans PC, Krams R. Effect of shear stress on vascular inflammation and plaque development. Curr Opin Lipidol 2007; 18:527-33. [PMID: 17885423 DOI: 10.1097/mol.0b013e3282ef7716] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE OF REVIEW This review describes evidence that shear stress acts through modulation of inflammation and by that process affects atherogenesis and plaque composition. RECENT FINDINGS In low shear stress regions antiatherogenic transcription factors are downregulated and pro-atherogenic transcription factors are upregulated. Consequently, inflammatory cells may home low shear stress regions more easily to the plaques because of increased expression of adhesion factors, a decreased rolling speed and an increased expression of chemokines, thereby changing the composition of the plaques into a more vulnerable phenotype. In contrast, in advanced plaque development vascular lumen decreases and shear stress increases, especially upstream of the plaques. The predominant upstream location of lipids induces a prevalent upstream location of inflammatory cells leading to localized plaque rupture. SUMMARY Shear stress has been shown to play a role in plaque induction, plaque progression and plaque rupture. The mechanism for plaque induction seems to differ from the role of shear stress for plaque rupture, whereby the former mechanism is induced by low shear stress and the latter by high shear stress.
Collapse
|
98
|
Abstract
Resolution of inflammatory responses is the regulatory process that prevents prolonged inflammation, thus avoiding diseases such as atherosclerosis, rheumatoid arthritis and transplant rejection. There are various different aspects to this process which are discussed briefly here and in the accompanying papers from this Focused Meeting.
Collapse
|
99
|
Partridge J, Carlsen H, Enesa K, Chaudhury H, Zakkar M, Luong L, Kinderlerer A, Johns M, Blomhoff R, Mason JC, Haskard DO, Evans PC. Laminar shear stress acts as a switch to regulate divergent functions of NF-kappaB in endothelial cells. FASEB J 2007; 21:3553-61. [PMID: 17557931 DOI: 10.1096/fj.06-8059com] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Regions of the arterial tree exposed to laminar flow, which exerts high shear stress, are protected from inflammation, endothelial cell (EC) death and atherosclerosis. TNFalpha activates NF-kappaB transcription factors, which potentially exert dual functions by inducing both proinflammatory and cytoprotective transcripts. We assessed whether laminar shear stress protects EC by modulating NF-kappaB function. Human umbilical vein EC (HUVEC) were cultured under shear stress (12 dynes/cm2 for 16 h) using a parallel-plate flow chamber or were maintained in static conditions. Comparative real-time PCR revealed that preshearing significantly alters transcriptional responses to TNFalpha by enhancing the expression of cytoprotective molecules (Bcl-2, MnSOD, GADD45beta, A1) and suppressing proinflammatory transcripts (E-selectin, VCAM-1, IL-8). We demonstrated using assays of nuclear localization, NF-kappaB subunit phosphorylation, DNA-binding, and transcriptional activity that NF-kappaB is activated by TNFalpha in presheared HUVEC. Furthermore, a specific inhibitor revealed that NF-kappaB is essential for the induction of cytoprotective transcripts in presheared EC. Finally, we observed that NF-kappaB can be activated in vascular endothelium exposed to laminar shear stress in NF-kappaB-luciferase reporter mice, thus validating our cell culture experiments. We conclude that shear stress primes EC for enhanced NF-kappaB-dependent cytoprotective responsiveness while attenuating proinflammatory activation. Thus modulation of NF-kappaB function may underlie the atheroprotective effects of laminar shear stress.
Collapse
|
100
|
Marques C, Guo W, Pereira P, Taylor A, Patterson C, Evans PC, Shang F. The triage of damaged proteins: degradation by the ubiquitin-proteasome pathway or repair by molecular chaperones. FASEB J 2006; 20:741-3. [PMID: 16469848 PMCID: PMC2100384 DOI: 10.1096/fj.05-5080fje] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Accumulation of damaged proteins is causally related to many age-related diseases. The ubiquitin-proteasome pathway (UPP) plays a role in selective degradation of damaged proteins, whereas molecular chaperones, such as heat shock proteins, are involved in refolding denatured proteins. This work demonstrates for the first time that the UPP and molecular chaperones work in a competitive manner and that the fates of denatured proteins are determined by the relative activities of the UPP and molecular chaperones. Enhanced UPP activity suppresses the refolding of denatured proteins whereas elevated chaperone activity inhibits the degradation of denatured proteins. CHIP, a co-chaperone with E3 activity, plays a pivotal role in determining the fates of the damaged proteins. The delicate balance between UPP-mediated degradation and refolding of denatured proteins is governed by relative levels of CHIP and other molecular chaperones. Isopeptidases, the enzymes that reverse the actions of CHIP, also play an important role in determining the fate of denatured proteins.
Collapse
|