Protein disulfide-isomerase mediates delivery of nitric oxide redox derivatives into platelets

Bell, Susannah E.; Shah, Chirag; Gordge, Michael P.

doi:10.1042/bj20061146

Cited by 37 publications

(43 citation statements)

References 35 publications

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“…As shown in Figure 2A, the 2 mAbs used at 10 g/mL significantly enhanced the Xa generation on TF-EC, whereas the 2 polyclonal antibodies did not. In addition to RL-90 mAb, a reported inhibitor of PDI enzymatic activity in vitro 40,41 and in vivo, 14,29 we found that BD34 mAb was the most potent inhibitor in our screening. We used an insulin reduction assay to test the functional properties of BD34 mAb against purified bovine PDI ( Figure 2B).…”

Section: Extracellular Pdi Inhibition Enhances Coagulationmentioning

confidence: 82%

“…In comparison, RL-90 inhibition of PDI activity was reportedly approximately 25% to 30%. 41 Next, we sought to confirm these findings in ECs expressing endogenous TF in response to tumor necrosis factor (TNF). As shown in Figure 2C, PDI inhibition with BD34 mAb significantly BLOOD, 12 AUGUST 2010 ⅐ VOLUME 116, NUMBER 6 For personal use only.…”

Section: Extracellular Pdi Inhibition Enhances Coagulationmentioning

confidence: 95%

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Extracellular protein disulfide isomerase regulates coagulation on endothelial cells through modulation of phosphatidylserine exposure

Popescu

Lupu

2010

Blood

109

112

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Tissue factor (TF) is the cellular receptor for plasma protease factor VIIa (FVIIa), and the TF-FVIIa complex initiates coagulation in both hemostasis and thrombosis. Cell surface-exposed TF is mainly cryptic and requires activation to fully exhibit the procoagulant potential. Recently, the protein disulfide isomerase (PDI) has been hypothesized to regulate TF decryption through the redox switch of an exposed disulfide in TF extracellular domain. In this study, we analyzed PDI contribution to coagulation using an in vitro endothelial cell model. In this model, extracellular PDI is detected by imaging and flow cytometry. Inhibition of cell surface PDI induces a marked increase in TF procoagulant function, whereas exogenous addition of PDI inhibits TF decryption. The coagulant effects of PDI inhibition were sensitive to annexin V treatment, suggesting exposure of phosphatidylserine (PS), which was confirmed by prothrombinase assays and direct labeling.In contrast, exogenous PDI addition enhanced PS internalization. Analysis of fluorescent PS revealed that PDI affects both the apparent flippase and floppase activities on endothelial cells. In conclusion, we identified a new mechanism for PDI contribution to coagulation on endothelial cells, namely, the regulation of PS exposure, where PDI acts as a negative regulator of coagulation. (Blood. 2010; 116(6):993-1001) IntroductionTissue factor (TF) is a transmembrane glycoprotein that binds with high affinity to the plasma protease factor VII in either zymogen (FVII) or activated form (FVIIa). The formation of the TF-FVIIa complex is crucial for initiation of coagulation, leading to thrombin generation and fibrin formation. Although the primary role of TF-FVIIa is to maintain hemostasis after vascular injury, aberrant activation of coagulation underlies thrombosis, the major cause of mortality in most industrialized countries. 1 In physiologic conditions, initiation of coagulation is maintained silent by restricting the exposure of TF to the plasma factors. 2,3 In pathologic conditions, however, TF may become exposed on the endothelium 4,5 and on circulating monocytes. 6 At these sites, TF can initiate thrombotic events associated with sepsis, 4,7 cancer, 8,9 or atherosclerosis. 10,11 Multiple in vitro studies have indicated that most of the cell-exposed TF is "cryptic," thus not fully active toward coagulation, 12,13 and TF "decryption" has been proposed as the initial step in the activation of coagulation. 14 Although the molecular mechanisms of TF decryption are not completely understood, many of the stimuli that decrypt TF also increase the exposure of phosphatidylserine (PS), [15][16][17][18] which is known to enhance coagulation. PS-independent mechanisms of TF decryption have also been postulated, such as TF self-association, 19 association with lipid rafts, [20][21][22] and the redox switch of an exposed disulfide in the membrane proximal domain of TF. 23 Protein disulfide isomerase (PDI) is an oxidoreductase 24 localized mainly in the endoplasmic reticulum (ER...

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Section: Extracellular Pdi Inhibition Enhances Coagulationmentioning

confidence: 82%

Section: Extracellular Pdi Inhibition Enhances Coagulationmentioning

confidence: 95%

Extracellular protein disulfide isomerase regulates coagulation on endothelial cells through modulation of phosphatidylserine exposure

Popescu

Lupu

2010

Blood

109

112

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“…13 Inhibition of PDI blocks the delivery of NO from the physiologic NO donor, S-nitrosoglutathione, into both megakaryocytes 31 and into platelets. 35 PDI-mediated transnitrosylation is proposed to occur via the delivery of NO into cell membranes in the form of N 2 O 3 .…”

Section: S-nitrosylation Of Thiol Isomerasesmentioning

confidence: 99%

Vascular thiol isomerases

Flaumenhaft

Furie

2016

Blood

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Thiol isomerases are multifunctional enzymes that influence protein structure via their oxidoreductase, isomerase, and chaperone activities. These enzymes localize at high concentrations in the endoplasmic reticulum of all eukaryotic cells where they serve an essential function in folding nascent proteins. However, thiol isomerases can escape endoplasmic retention and be secreted and localized on plasma membranes. Several thiol isomerases including protein disulfide isomerase, ERp57, and ERp5 are secreted by and localize to the membranes of platelets and endothelial cells. These vascular thiol isomerases are released following vessel injury and participate in thrombus formation. Although most of the activities of vascular thiol isomerases that contribute to thrombus formation are yet to be defined at the molecular level, allosteric disulfide bonds that are modified by thiol isomerases have been described in substrates such as αIIbβ3, αvβ3, GPIbα, tissue factor, and thrombospondin. Vascular thiol isomerases also act as redox sensors. They respond to the local redox environment and influence S-nitrosylation of surface proteins on platelets and endothelial cells. Despite our rudimentary understanding of the mechanisms by which thiol isomerases control vascular function, the clinical utility of targeting them in thrombotic disorders is already being explored in clinical trials.

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“…149, 150 The functional effects of PDI on eNOS signaling remain elusive, but probably involve interactions with metal binding proteins. For example, metallothionein is a small (7kDa) cysteine-rich protein that functions as an antioxidant and intracellular buffer against the toxic effects of non-essential metals.…”

Section: Protein Disulfide Isomerase (Pdi)mentioning

confidence: 99%

Subcellular Localization of Oxidants and Redox Modulation of Endothelial Nitric Oxide Synthase

Maron

Michel

2012

Circ J

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Reactive oxygen species (ROS) have long been viewed as deleterious chemicals that lead to oxidative stress. More recently, ROS, especially the stable ROS hydrogen peroxide (H2O2), have been shown to have roles in normal physiological responses in vascular cells. Endothelial nitric oxide synthase (eNOS) is dynamically targeted to plasmalemmal caveolae, and represents the principal enzymatic source of nitric oxide (NO • ) in the vascular wall. eNOS maintains normal vascular tone and inhibits the clinical expression of many cardiovascular diseases. Increases in oxidative stress are associated with eNOS dysfunction. In a paradigm shift in the conceptual framework linking redox biochemistry and vascular function, H2O2 has been established as a physiological mediator in signaling pathways, yet the intracellular sources of H2O2 and their regulation remain incompletely understood. The subcellular distributions of ROS and of ROS-modified proteins critically influence the redox-sensitive regulation of eNOS-dependent pathways. ROS localization in specific subcellular compartments can lead to selective oxidative modifications of eNOS and eNOS-associated proteins. Likewise, the dynamic targeting of eNOS and other signaling proteins influences their interactions with reactive nitrogen species and ROS that are also differentially distributed within the cell. Thus, the subcellular distribution both of eNOS and redox-active biomolecules serves as a critical basis for the control of the "redox switch" that influences NO• - and oxidant-regulated signaling pathways. Here we discuss the biochemical factors, cellular determinants, and molecular mechanisms that modulate redox-sensitive regulation of eNOS and NO tion of eNOS is dynamically regulated 9 and the enzyme is thus exposed to different concentrations of ROS depending upon where in the cell the protein is localized. Alterations in eNOS function due to changes in ROS levels may reflect either physiological or pathological responses in both normal cells and in vascular disease states. The relationship between impaired eNOS activity and the development of vascular dysfunction has been extensively studied: NO • is a potent vasodilator molecule that also attenuates platelet aggregation, vascular smooth muscle cell (VSMC) proliferation, and negative vascular remodeling. 10 Collectively, these properties contribute to the prevention of intermediate pathophenotypes of vascular disease, including cardiac and/or vascular hypertrophy, fibrosis, and atherosclerosis. In counterpoise to these deleterious effects of ROS, there also appears to be a key physiological role for H2O2 in eNOS regulation. 11 Elucidating the redoxdependent mechanisms involved in the physiological and pathophysiological regulation of eNOS by ROS will provide critical new insights into vascular disease states and may lead to the identification of novel treatment targets related to eNOS and eNOS-modulated vascular responses.

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Protein disulfide-isomerase mediates delivery of nitric oxide redox derivatives into platelets

Cited by 37 publications

References 35 publications

Extracellular protein disulfide isomerase regulates coagulation on endothelial cells through modulation of phosphatidylserine exposure

Extracellular protein disulfide isomerase regulates coagulation on endothelial cells through modulation of phosphatidylserine exposure

Vascular thiol isomerases

Subcellular Localization of Oxidants and Redox Modulation of Endothelial Nitric Oxide Synthase

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