Circulating Factor Seven Activating Protease (FSAP) in the Hyperacute Phase of Stroke

Background. Factor VII activating protease (FSAP) is a circulating serine protease that could be involved in the pathophysiology of stroke. We analyzed the temporal changes in FSAP antigen and FSAP activity after acute cerebral ischemia (ACI) and tested if FSAP could be used to differentiate between stroke subtypes in the hyperacute phase (<4.5 hours after symptom onset). Methods. Of the 118 suspected stroke patients enrolled, 76 had ACI; of which 20 suffered from large vessel occlusion (LVO), 19 had intracerebral hemorrhage (ICH), and 23 had stroke mimics. Median time from symptom onset to the two plasma sample collections, <4.5 hours, were 66 and 107 minutes for the entire study population. Additional samples were collected up to 90 days post stroke in a subset of ACI patients (). FSAP antigen, FSAP activity, FSAP-α2-antiplasmin-complex (FSAP-AP complex), and nucleosomes were measured by activity assays or ELISA. Results. ACI patients treated with tissue plasminogen activator (tPA) had elevated FSAP hours () that subsequently normalized after 6 hours. FSAP-AP complex levels decreased significantly from <4.5 hours () to 6 hours after symptom onset. tPA did not increase FSAP activity significantly in plasma in vitro. FSAP antigen significantly hours after symptom onset in LVO () and ICH () patients. FSAP could not differentiate ACI from ICH or strokes (ACI and ICH) from stroke mimics. FSAP did not correlate with stroke severity. Conclusion. LVO and ICH seem to influence FSAP levels in the hyperacute phase of stroke, but FSAP does not differentiate between stroke subtypes in a hyperacute setting.publishedVersio

Components of the Plasminogen Activation System Promote Engraftment of Porous Polyethylene Biomaterial via Common and Distinct Effects

Rapid fibrovascularization is a prerequisite for successful biomaterial engraftment. In addition to their well-known roles in fibrinolysis, urokinase-type plasminogen activator (uPA) and tissue plasminogen activator (tPA) or their inhibitor plasminogen activator inhibitor-1 (PAI-1) have recently been implicated as individual mediators in non-fibrinolytic processes, including cell adhesion, migration, and proliferation. Since these events are critical for fibrovascularization of biomaterial, we hypothesized that the components of the plasminogen activation system contribute to biomaterial engraftment. Employing in vivo and ex vivo microscopy techniques, vessel and collagen network formation within porous polyethylene (PPE) implants engrafted into dorsal skinfold chambers were found to be significantly impaired in uPA-, tPA-, or PAI-1-deficient mice. Consequently, the force required for mechanical disintegration of the implants out of the host tissue was significantly lower in the mutant mice than in wild-type controls. Conversely, surface coating with recombinant uPA, tPA, non-catalytic uPA, or PAI-1, but not with non-catalytic tPA, accelerated implant vascularization in wild-type mice. Thus, uPA, tPA, and PAI-1 contribute to the fibrovascularization of PPE implants through common and distinct effects. As clinical perspective, surface coating with recombinant uPA, tPA, or PAI-1 might provide a novel strategy for accelerating the vascularization of this biomaterial

The G534E polymorphism of the gene encoding the factor VII–activating protease is associated with cardiovascular risk due to increased neointima formation

The G534E polymorphism (Marburg I [MI]) of factor VII–activating protease (FSAP) is associated with carotid stenosis and cardiovascular disease. We have previously demonstrated that FSAP is present in atherosclerotic plaques and it is a potent inhibitor of vascular smooth muscle proliferation and migration in vitro. The effect of wild-type (WT)- and MI-FSAP on neointima formation in the mouse femoral artery after wire-induced injury was investigated. Local application of WT-FSAP led to a 70% reduction in the neointima formation, and this effect was dependent on the protease activity of FSAP. MI-FSAP did not inhibit neointima formation in vivo. This is due to a reduced proteolytic activity of MI-FSAP, compared to WT-FSAP, toward platelet-derived growth factor BB, a key mediator of neointima development. The inability of MI-FSAP to inhibit vascular smooth muscle accumulation explains the observed linkage between the MI-polymorphism and increased cardiovascular risk. Hence, FSAP has a protective function in the vasculature, and analysis of MI polymorphism is likely to be clinically relevant in restenosis

Factor VII Activating Protease Polymorphism (G534E) Is Associated with Increased Risk for Stroke and Mortality

Introduction. The FSAP-Marburg I polymorphism (1704G > A), which reduces FSAP activity, is associated with late complications of carotid stenosis in humans. Therefore, this study examines the influence of the Marburg I polymorphism and the closely linked Marburg II polymorphism (1280G > C) on various cardiovascular outcomes in two large independent study populations. Methods. The two Marburg polymorphisms in the HABP2 gene encoding FSAP were genotyped in a large population of elderly patients at risk for vascular disease (the PROSPER-study, n = 5804) and in a study population treated with a percutaneous coronary intervention (the GENDER-study, n = 3104). Results. In the PROSPER study, the Marburg I polymorphism was associated with an increased risk of clinical stroke (HR: 1.60, 95% CI: 1.13–2.28) and all-cause mortality (HR: 1.33, 95% CI: 1.04–1.71). In the GENDER study carriers of this variant seemed at lower risk of developing restenosis (HR: 0.59, 95% CI: 0.34–1.01). The Marburg II polymorphism showed similar but weaker results. Conclusion. The increase in stroke risk in Marburg I carriers could be due to differential effects on smooth muscle cells and on matrix metalloproteinases, thereby influencing plaque stability. The possible protective effect on restenosis could be the result of reduced activation of zymogens, which are involved in hemostasis and matrix remodeling

Identification of a Phage Display-Derived Peptide Interacting with the N-Terminal Region of Factor VII Activating Protease (FSAP) Enables Characterization of Zymogen Activation

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Проблемы научно-технического прогресса в бурении скважин: сборник докладов Всероссийской научно-технической конференции с международным участием , посвященной 60-летию кафедры бурения скважин, Томск, 2014 г.

В материалах сборника представлены результаты исследований научных работников по важным вопросам бурения геологоразведочных, технических, нефтяных и газовых скважин, проведения горно-разведочных выработок: разрушение горных пород, упрочнение породоразрушающего инструмента, скважинная гидродобыча руды, подземное выщелачивание урана, новые подходы по изучению буровых растворов, цементирование обсадных колонн, поиск новых путей получения информации с забоя в процессе бурения; даны решения ряда актуальных вопросов при проведении горноразведочных выработок

The pseudophosphatase STYX targets the F‐box of FBXW7 and inhibits SCF^(FBXW7) function

The F‐box protein FBXW7 is the substrate‐recruiting subunit of an SCF ubiquitin ligase and a major tumor‐suppressor protein that is altered in several human malignancies. Loss of function of FBXW7 results in the stabilization of numerous proteins that orchestrate cell proliferation and survival. Little is known about proteins that directly regulate the function of this protein. In the current work, we have mapped the interactome of the enigmatic pseudophosphatase STYX. We reasoned that a catalytically inactive phosphatase might have adopted novel mechanisms of action. The STYX interactome contained several F‐box proteins, including FBXW7. We show that STYX binds to the F‐box domain of FBXW7 and disables its recruitment into the SCF complex. Therefore, STYX acts as a direct inhibitor of FBXW7, affecting the cellular levels of its substrates. Furthermore, we find that levels of STYX and FBXW7 are anti‐correlated in breast cancer patients, which affects disease prognosis. We propose the STYX–FBXW7 interaction as a promising drug target for future investigations

The pseudophosphatase STYX targets the F‐box of FBXW7 and inhibits SCF^(FBXW7) function

The F‐box protein FBXW7 is the substrate‐recruiting subunit of an SCF ubiquitin ligase and a major tumor‐suppressor protein that is altered in several human malignancies. Loss of function of FBXW7 results in the stabilization of numerous proteins that orchestrate cell proliferation and survival. Little is known about proteins that directly regulate the function of this protein. In the current work, we have mapped the interactome of the enigmatic pseudophosphatase STYX. We reasoned that a catalytically inactive phosphatase might have adopted novel mechanisms of action. The STYX interactome contained several F‐box proteins, including FBXW7. We show that STYX binds to the F‐box domain of FBXW7 and disables its recruitment into the SCF complex. Therefore, STYX acts as a direct inhibitor of FBXW7, affecting the cellular levels of its substrates. Furthermore, we find that levels of STYX and FBXW7 are anti‐correlated in breast cancer patients, which affects disease prognosis. We propose the STYX–FBXW7 interaction as a promising drug target for future investigations