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Pathway Inhibitor (pathway + inhibitor)
Kinds of Pathway Inhibitor Selected AbstractsFractalkine reduces N -methyl- d -aspartate-induced calcium flux and apoptosis in human neurons through extracellular signal-regulated kinase activationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2004Kumaran Deiva Abstract Our purpose was to investigate in human neurons the neuroprotective pathways induced by Fractalkine (FKN) against glutamate receptor-induced excitotoxicity. CX3CR1 and FKN are expressed constitutively in the tested human embryonic primary neurons and SK-N-SH, a human neuroblastoma cell line. Microfluorometry assay demonstrated that CX3CR1 was functional in 44% of primary neurons and in 70% of SK-N-SH. Fractalkine induced ERK1/2 phosphorylation within 1 min and Akt phosphorylation after 10 min, and both phosphorylation decreased after 20 min. No p38 and SAPK/JNK activation was observed after FKN treatment. Application of FKN triggered a 53% reduction of the NMDA-induced neuronal calcium influx, which was insensitive to pertussis toxin and LY294002 an inhibitor of Akt pathway, but abolished by PD98059, an ERK1/2 pathway inhibitor. Moreover, FKN significantly reduced neuronal NMDA-induced apoptosis, which was pertussis toxin insensitive and abolished in presence of PD98059 and LY294002. In conclusion, FKN protected human neurons from NMDA-mediated excitotoxicity in at least two ways with different kinetics: (i) an early ERK1/2 activation which reduced NMDA-mediated calcium flux; and (ii), a late Akt activation associated with the previously induced ERK1/2 activation. [source] Human airway trypsin-like protease induces amphiregulin release through a mechanism involving protease-activated receptor-2-mediated ERK activation and TNF ,-converting enzyme activity in airway epithelial cellsFEBS JOURNAL, Issue 24 2005Manabu Chokki Human airway trypsin-like protease (HAT), a serine protease found in the sputum of patients with chronic airway diseases, is an agonist of protease-activated receptor-2 (PAR-2). Previous results have shown that HAT enhances the release of amphiregulin (AR); further, it causes MUC5AC gene expression through the AR-epidermal growth factor receptor pathway in the airway epithelial cell line NCI-H292. In this study, the mechanisms by which HAT-induced AR release can occur were investigated. HAT-induced AR gene expression was mediated by extracellular signal-regulated kinase (ERK) pathway, as pretreatment of cells with ERK pathway inhibitor eliminated the effect of HAT on AR mRNA. Both HAT and PAR-2 agonist peptide (PAR-2 AP) induced ERK phosphorylation; further, desensitization of PAR-2 with a brief exposure of cells to PAR-2 AP resulted in inhibition of HAT-induced ERK phosphorylation, suggesting that HAT activates ERK through PAR-2. Moreover, PAR-2 AP induced AR gene expression subsequent to protein production in the cellular fraction through the ERK pathway indicating that PAR-2-mediated activation of ERK is essential for HAT-induced AR production. However, in contrast to HAT, PAR-2 AP could not cause AR release into extracellular space; it appears that activation of PAR-2 is not sufficient for HAT-induced AR release. Finally, HAT-induced AR release was eliminated by blockade of tumour necrosis factor ,-converting enzyme (TACE) by the TAPI-1 and RNA interference, suggesting that TACE activity is necessary for HAT-induced AR release. These observations show that HAT induces AR production through the PAR-2 mediated ERK pathway, and then causes AR release by a TACE-dependent mechanism. [source] Progestin upregulates G-protein-coupled receptor 30 in breast cancer cellsFEBS JOURNAL, Issue 10 2002Tytti M. Ahola A differential display method was used to study genes the expression of which is altered during growth inhibition induced by medroxyprogesterone acetate (MPA). A transcript of G-protein-coupled receptor 30 (GPR30) was upregulated by MPA in estrogen-treated MCF-7 breast cancer cells. Northern-blot analysis showed a progestin-specific primary target gene, which was enhanced by progesterone and different progestins, but not by dihydrotestosterone or dexamethasone, and which was abrogated by antiprogestin RU486. The dose-dependent and time-dependent increase in GPR30 mRNA expression correlated with MPA-induced growth inhibition in MCF-7 cells. Additionally, GPR30 upregulation by progestin correlated with growth inhibition when a comparison was made between different breast cancer cell lines. The ERK1/ERK2 pathway is capable of inducing progesterone receptor-dependent and ligand-dependent transcription. Thus we sought to establish whether different MAPK pathway inhibitors affect progestin-induced GPR30 mRNA regulation. The regulation of GPR30 was independent of ERK pathway activation, but the p38 pathway inhibitor induced GPR30 expression, which suggested a potential gene regulation pathway. These data demonstrate a new progestin target gene, the expression of which correlates with growth inhibition. [source] Hepatocyte growth factor promotes cell survival from Fas-mediated cell death in hepatocellular carcinoma cells via Akt activation and Fas-death,inducing signaling complex suppressionHEPATOLOGY, Issue 4 2000Atsushi Suzuki The Akt/PI-3 kinase pathway is a system essential for cell survival. In the current study, we showed that hepatocyte growth factor (HGF) activates the Akt/PI-3 kinase pathway to suppress Fas-mediated cell death in human hepatocellular carcinoma (HCC; 3 lines; SK-Hep1, HLE, and Chang Liver cell lines), hepatoblastoma (1 line; HepG2), and embryonic hepatocyte (1 line; WRL). Five tested cell lines showed the resistance to Fas-mediated cell death by the pretreatment of HGF. This HGF-induced cell survival was suppressed by wortmannin (Akt/PI-3 kinase pathway inhibitor), suggesting an involvement of Akt. When cells were pretreated with HGF, Fas-mediated cell death was suppressed, followed by Akt phosphorylation at Ser473. Fas-death,inducing signaling complex (DISC) formation, especially FADD and caspase 8 interaction, was suppressed by HGF and the suppression of the Akt/PI-3 kinase pathway by transient expression of PTEN, resulting in acquisition of Fas-DISC formation and Fas-mediated cell death in HGF-treated cells. We suggest that HGF promotes cell survival in hepatocyte-derived cell lines (HCC, hepatoblastoma, and embryonic hepatocyte) from Fas-mediated cell death via Fas-DISC suppression as a result of Akt activation. [source] Oxysterol-induced osteogenic differentiation of marrow stromal cells is regulated by Dkk-1 inhibitable and PI3-kinase mediated signalingJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2008Christopher M. Amantea Abstract Osteoporosis and its complications cause morbidity and mortality in the aging population, and result from increased bone resorption by osteoclasts in parallel with decreased bone formation by osteoblasts. A widely accepted strategy for improving bone health is targeting osteoprogenitor cells in order to stimulate their osteogenic differentiation and bone forming properties through the use of osteoinductive/anabolic factors. We previously reported that specific naturally occurring oxysterols have potent osteoinductive properties, mediated in part through activation of hedgehog signaling in osteoprogenitor cells. In the present report, we further demonstrate the molecular mechanism(s) by which oxysterols induce osteogenesis. In addition to activating the hedgehog signaling pathway, oxysterol-induced osteogenic differentiation is mediated through a Wnt signaling-related, Dkk-1-inhibitable mechanism. Bone marrow stromal cells (MSC) treated with oxysterols demonstrated increased expression of osteogenic differentiation markers, along with selective induced expression of Wnt target genes. These oxysterol effects, which occurred in the absence of ,-catenin accumulation or TCF/Lef activation, were inhibited by the hedgehog pathway inhibitor, cyclopamine, and/or by the Wnt pathway inhibitor, Dkk-1. Furthermore, the inhibitors of PI3-Kinase signaling, LY 294002 and wortmanin, inhibited oxysterol-induced osteogenic differentiation and induction of Wnt signaling target genes. Finally, activators of canonical Wnt signaling, Wnt3a and Wnt1, inhibited spontaneous, oxysterol-, and Shh-induced osteogenic differentiation of bone marrow stromal cells, suggesting the involvement of a non-canonical Wnt pathway in pro-osteogenic differentiation events. Osteogenic oxysterols are, therefore, important small molecule modulators of critical signaling pathways in pluripotent mesenchymal cells that regulate numerous developmental and post-developmental processes. J. Cell. Biochem. 105: 424,436, 2008. © 2008 Wiley-Liss, Inc. [source] Vitamin E protected cultured cortical neurons from oxidative stress-induced cell death through the activation of mitogen-activated protein kinase and phosphatidylinositol 3-kinaseJOURNAL OF NEUROCHEMISTRY, Issue 4 2006Yumiko Numakawa Abstract The role of vitamin E in the CNS has not been fully elucidated. In the present study, we found that pre-treatment with vitamin E analogs including ,T (,-tocopherol), ,T3 (, -tocotrienol), ,T, and ,T3 for 24 h prevented the cultured cortical neurons from cell death in oxidative stress stimulated by H2O2, while Trolox, a cell-permeable analog of ,T, did not. The preventive effect of ,T was dependent on de novo protein synthesis. Furthermore, we found that ,T exposure induced the activation of both the MAP kinase (MAPK) and PI3 kinase (PI3K) pathways and that the ,T-dependent survival effect was blocked by the inhibitors, U0126 (an MAPK pathway inhibitor) or LY294002 (a PI3K pathway inhibitor). Interestingly, the up-regulation of Bcl-2 (survival promoting molecule) was induced by ,T application. The up-regulation of Bcl-2 did not occur in the presence of U0126 or LY294002, suggesting that ,T-up-regulated Bcl-2 is mediated by these kinase pathways. These observations suggest that vitamin E analogs play an essential role in neuronal maintenance and survival in the CNS. [source] Atorvastatin or transgenic expression of TFPI inhibits coagulation initiated by anti-nonGal IgG binding to porcine aortic endothelial cellsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2010C. C. LIN Summary.,Background:,Intravascular thrombosis remains a barrier to successful xenotransplantation. Tissue factor (TF) expression on porcine aortic endothelial cells (PAECs), which results from their activation by xenoreactive antibodies (Abs) to Gal,1,3Gal (Gal) and subsequent complement activation, plays an important role. Objectives:,The present study aimed to clarify the role of Abs directed against nonGal antigens in the activation of PAECs to express functional TF and to investigate selected methods of inhibiting TF activity. Methods:,PAECs from wild-type (WT), ,1,3-galactosyltransferase gene-knockout (GT-KO) pigs, or pigs transgenic for CD46 or tissue factor pathway inhibitor (TFPI), were incubated with naïve baboon serum (BS) or sensitized BS (with high anti-nonGal Ab levels). TF activity of PAECs was assessed. Results:,Only fresh, but not heat-inactivated (HI), naïve BS activated WT PAECs to express functional TF. Similarly, PAECs from CD46 pigs were resistant to activation by naïve BS, but not to activation by fresh or HI sensitized BS. HI sensitized BS also activated GT-KO PAECs to induce TF activity. TF expression on PAECs induced by anti-nonGal Abs was inhibited if serum was pretreated with (i) an anti-IgG Fab Ab or (ii) atorvastatin, or (iii) when PAECs were transgenic for TFPI. Conclusions:,Anti-nonGal IgG Abs activated PAECs to induce TF activity through a complement-independent pathway. This implies that GT-KO pigs expressing a complement-regulatory protein may be insufficient to prevent the activation of PAECs. Genetic modification with an ,anticoagulant' gene (e.g. TFPI) or a therapeutic approach (e.g. atorvastatin) will be required to prevent coagulation dysregulation after pig-to-primate organ transplantation. [source] Interaction between tissue factor pathway inhibitor and factor V levels on the risk of venous thrombosisJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2010A. E. A. DAHM No abstract is available for this article. [source] Regulation of TFPI function by protein SJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2009T. M. HACKENG Summary., Protein S is an anticoagulant cofactor of full-length tissue factor pathway inhibitor (TFPI) that facilitates optimal factor Xa-inhibition and efficient down-regulation of thrombin generation in plasma. Protein S and TFPI are constitutively active in plasma and therefore provide an effective anticoagulant barrier against unwanted procoagulant activity in the circulation. In this review, we describe the current status on how TFPI-activity depends on protein S, and show that TFPI and protein S are major regulators of thrombin generation both in the absence and presence of activated protein C (APC). As there is covariation of plasma TFPI and protein S levels both in health and in disease, these findings suggest that the risk of venous thrombosis associated with protein S deficiency states might be in part explained by the accompanying low plasma TFPI levels. [source] Increased acquired activated protein C resistance in unselected patients with hematological malignanciesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2008H. F. S. NEGAARD Summary.,Background: We have previously found that activation of coagulation in patients with various hematological malignancies was apparently not initiated by tissue factor (TF). Acquired activated protein C (APC) resistance may be another mechanism responsible for such hypercoagulation, and has been demonstrated in patients with solid tumors, but not in patients with hematological malignancy. Objective: To investigate acquired APC resistance in a hypercoagulable cohort of patients with hematological malignancies. Patients/methods: Blood samples from 93 patients with acute myeloid leukemia (AML), chronic lymphatic leukemia, multiple myeloma, or non-Hodgkin's lymphoma, were analyzed before start and after completion of cancer therapy. APC resistance was measured using calibrated automated thrombography. The APC sensitivity ratio (APC-SR) was calculated as the ratio of the endogenous thrombin potential (ETP) determined in plasma probed with either APC or buffer. Results: Untreated patients were found to have higher APC-SR than healthy controls, and patients with AML had higher APC-SR as compared to the other diagnoses, both findings being consistent with acquired APC resistance. The acquired APC resistance was partly ameliorated with cancer treatment. Decreased levels of protein S and TF pathway inhibitor were inversely correlated to APC resistance. Conclusions: APC resistance may contribute to the hypercoagulable state in hematological malignancies. [source] Activity and regulation of glycoPEGylated factor VIIa analogsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2008S. GHOSH Summary.,Background:,Recombinant coagulation factor VIIa (rFVIIa) has proven to be a safe and effective drug for treatment of bleeding episodes in hemophilic patients with inhibitors. However, rFVIIa is cleared from the circulation relatively quickly. Protein modification with poly(ethylene glycol) (PEG) can prolong the circulatory lifetime of proteins but it could also impair protein function by molecular shielding of the protein surface. Objectives:, To characterize the interaction of glycoPEGylated rFVIIa , rFVIIa-10K PEG and rFVIIa-40K PEG , with tissue factor (TF), factor X (FX) and plasma inhibitors, tissue factor pathway inhibitor (TFPI) and antithrombin (AT). Methods:, The amidolytic and FX activation assays were employed to investigate the interaction of glycoPEGylated rFVIIa with its macromolecular substrate and inhibitors. Results:, Both the glycoPEGylated rFVIIa analogs exhibited similar amidolytic activity as that of rFVIIa in the absence or the presence of relipidated TF. The analogs were as effective as rFVIIa in activating FX in the absence of TF. In the presence of TF, the glycoPEGylated rFVIIa variants, relative to rFVIIa, were slightly less effective at lower concentrations, but no significant differences were found among them in activating FX at saturating concentrations. Both AT/heparin and TFPI effectively inhibited the glycoPEGylated rFVIIa bound to relipidated TF or TF on stimulated endothelial cells. In contrast to their normal interaction with TF, the glycoPEGylated rFVIIa variants appeared to interact poorly with phospholipids. Conclusions:, The glycoPEGylated rFVIIa variants retained their catalytic activity and interacted efficiently with TF, FX and the plasma inhibitors. Further work with appropriate in vitro and in vivo model systems is needed to determine the feasibility of using glycoPEGylated rFVIIa to improve therapeutic options for bleeding disorders. [source] Thrombin generation in acute coronary syndrome and stable coronary artery disease: dependence on plasma factor compositionJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2008K. BRUMMEL-ZIEDINS Summary.,Background:,Acute coronary syndrome (ACS) is associated with thrombin formation, triggered by ruptured or eroded coronary atheroma. We investigated whether thrombin generation based on circulating coagulation protein levels, could distinguish between acute and stable coronary artery disease (CAD). Methods and results:,Plasma coagulation factor (F) compositions from 28 patients with ACS were obtained after onset of chest pain. Similar data were obtained from 25 age- and sex-matched patients with stable CAD. All individuals took aspirin. Patients on anticoagulant therapy were excluded. The groups were similar in demographic characteristics, comorbidities and concomitant treatment. Using each individual's coagulation protein composition, tissue factor (TF) initiated thrombin generation was assessed both computationally and empirically. TF pathway inhibitor (TFPI), antithrombin (AT), factor II (FII) and FVIII differed significantly (P < 0.01) between the groups, with levels of FII, FVIII and TFPI higher and AT lower in ACS patients. When thrombin generation profiles from individuals in each group were compared, simulated maximum thrombin levels (P < 0.01) and rates (P < 0.01) were 50% higher with ACS while the initiation phases of thrombin generation were shorter. Empirical reconstructions of the populations reproduced the thrombin generation profiles generated by the computational model. The differences between the thrombin generation profiles for each population were primarily dependent upon the collective contribution of AT, FII and FVIII. Conclusion:,Simulations of thrombin formation based on plasma composition can discriminate between acute and stable CAD. [source] Combined tissue factor pathway inhibitor and thrombomodulin deficiency produces an augmented hypercoagulable state with tissue-specific fibrin depositionJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2008S. A. MARONEY Summary.,Background and Objective:,Tissue factor pathway inhibitor (TFPI) and thrombomodulin (TM) are endothelial-associated anticoagulant proteins thought to control hemostasis in specific vascular beds. Here, we have examined the consequences of TFPI deficiency in the presence of a compounding procoagulant state caused by reduced TM function. Methods and results:,TFPI+/,/TMpro/pro mice are born at less than expected frequency in either TFPI+/,/TMpro/+ or TMpro/pro mothers but are born at near the expected frequency in TMpro/+ mothers. Adult TFPI+/,/TMpro/pro mice have elevated thrombin,antithrombin complex and increased thrombus volume in an electrical injury model of venous thrombosis. In striking contrast to mice with single deficiency of TFPI or TM, TFPI+/,/TMpro/pro mice exhibit augmented fibrin deposition not only in the liver, but also in the cerebral microvasculature. Conclusions:,TFPI+/,/TMpro/pro mice exhibit partial intrauterine lethality when carried by mothers with an underlying prothrombotic state, providing the first experimental evidence in an animal model that TFPI-dependent control of hemostasis in the vascular bed of the placenta fulfills a critical role for successful pregnancy outcome. In addition to the placenta, partial TFPI deficiency interacts with decreased TM function in an organ selective manner to produce fibrin deposition in other specific vascular beds, the liver and brain. [source] Tissue factor-dependent blood coagulation is enhanced following delivery irrespective of the mode of deliveryJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2007K. BOER Summary. Background:,The risk of thrombosis is clearly increased in the postpartum period. Mice with a targeted deletion of the transmembrane domain of tissue factor (TF) develop serious activation of blood coagulation and widespread thrombosis after delivery. Objective and methods:,We hypothesized that TF, abundantly present in placental tissue, is released during delivery, resulting in the activation of blood coagulation. We measured sensitive markers for TF-dependent activation of coagulation before and after induction of labor in two groups: a vaginal delivery (VAG) group and a cesarean section (CS) group.Results:,One hour after delivery, soluble TF (sTF) significantly increased in both groups [VAG group (mean ± SD) 226 ± 42 to 380 ± 42 pg mL,1 and CS group 193 ± 17 to 355 ± 44 pg mL,1]. The day after delivery, sTF was somewhat less increased. Both groups also showed an increase in factor VIIa, indicating activation of the TF pathway of coagulation. Indeed, after delivery, TF-dependent coagulation, as measured by the TF clotting time assay, was significantly enhanced. Increased plasma levels of prothrombin fragment 1 + 2 and thrombin,antithrombin complexes demonstrated thrombin generation following delivery. TF pathway-dependent activation of coagulation upon delivery was not blocked by TF pathway inhibitor and was not dependent on the mode of delivery.Conclusion:,The postdelivery increase in TF-dependent activation of coagulation is likely to be a natural mechanism to prevent excessive blood loss during and after delivery, and may also indicate a novel mechanism by which puerperal women have an increased risk of venous thromboembolism. [source] Fibronectin-adherent monocytes express tissue factor and tissue factor pathway inhibitor whereas endotoxin-stimulated monocytes primarily express tissue factor: physiologic and pathologic implicationsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2007M. S. BAJAJ Summary Background:,Monocytes are critical cells in initiating physiologic and/or pathologic tissue factor (TF)-induced intravascular and extravascular coagulation. Monocytes constitutively express small amounts of TF and tissue factor pathway inhibitor (TFPI). Non-adherent lipopolysaccharide (LPS)-stimulated monocytes express significant amounts of TF; however, increased expression of TFPI by these cells is controversial. Further, whether fibronectin-adherent monocytes (mimicking conditions in the extravascular space) express sufficient TFPI to inhibit TF-procoagulant activity (PCA) is unknown.Objective:,To compare TF and TFPI expression by fibronectin-adherent and LPS-stimulated non-adherent monocytes.Methods:,Monocytes were isolated from normal peripheral blood, adhered to fibronectin or stimulated with lipopolysaccharide (LPS) under non-adherent conditions and examined for expression of TF and TFPI using quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR), ELISA and factor X (FX) activation.Results:,Under LPS-free conditions, the fibronectin-adherent monocyte TF mRNA, antigen and activity were markedly upregulated. Notably, cell and microparticle (MP)-associated TF and alternatively spliced TF (asTF) were all upregulated. TFPI mRNA and antigen were also upregulated in the fibronectin-adherent monocytes, which significantly inhibited TF-PCA. TFPI mRNAs for both alpha and beta forms were detected. The peak in TFPI activity occurred in tandem with the peak in TF-PCA. In contrast, LPS-stimulated monocytes, which expressed cell and MP-associated TF and asTF, demonstrated only minimal expression of TFPI as determined by mRNA, antigen or inhibition of TF activity.Conclusion:,Both LPS-stimulated and fibronectin-adherent monocytes demonstrate a procoagulant phenotype by expressing TF but only fibronectin-adherent monocytes express significant amounts of TFPI to control thrombin generation and fibrin formation in the context of extravascular space. [source] Efficacy and safety of recombinant human soluble thrombomodulin (ART-123) in disseminated intravascular coagulation: results of a phase III, randomized, double-blind clinical trialJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2007H. SAITO Summary.,Background: Soluble thrombomodulin is a promising therapeutic natural anticoagulant that is comparable to antithrombin, tissue factor pathway inhibitor and activated protein C. Objectives: We conducted a multicenter, double-blind, randomized, parallel-group trial to compare the efficacy and safety of recombinant human soluble thrombomodulin (ART-123) to those of low-dose heparin for the treatment of disseminated intravascular coagulation (DIC) associated with hematologic malignancy or infection. Methods: DIC patients (n = 234) were assigned to receive ART-123 (0.06 mg kg,1 for 30 min, once daily) or heparin sodium (8 U kg,1 h,1 for 24 h) for 6 days, using a double-dummy method. The primary efficacy endpoint was DIC resolution rate. The secondary endpoints included clinical course of bleeding symptoms and mortality rate at 28 days. Results: DIC was resolved in 66.1% of the ART-123 group, as compared with 49.9% of the heparin group [difference 16.2%; 95% confidence interval (CI) 3.3,29.1]. Patients in the ART-123 group also showed more marked improvement in clinical course of bleeding symptoms (P = 0.0271). The incidence of bleeding-related adverse events up to 7 days after the start of infusion was lower in the ART-123 group than in the heparin group (43.1% vs. 56.5%, P = 0.0487). Conclusions: When compared with heparin therapy, ART-123 therapy more significantly improves DIC and alleviates bleeding symptoms in DIC patients. [source] Postinjury vascular intimal hyperplasia in mice is completely inhibited by CD34+ bone marrow-derived progenitor cells expressing membrane-tethered anticoagulant fusion proteinsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2006D. CHEN Summary.,Background:,Coagulation proteins promote neointimal hyperplasia and vascular remodelling after vessel injury, but the precise mechanisms by which they act in vivo remain undetermined. Objectives:,This study, using an injury model in which the neointima is derived from bone marrow (BM)-derived cells, compared inhibition of tissue factor or thrombin on either BM-derived or existing vascular smooth muscle cells. Methods:,Two transgenic (Tg) mouse strains expressing membrane-tethered tissue factor pathway inhibitor (TFPI) or hirudin (Hir) fusion proteins driven by an , smooth muscle actin (SMA) promoter were generated (, -TFPI-Tg and , -Hir-Tg) and the phenotype after wire-induced endovascular injury was compared with that in wild-type (WT) controls. Results:,WT mice developed progressive neointimal expansion, whereas injury in either Tg was followed by repair back to a preinjured state. This was also seen when WT mice were reconstituted with BM from Tg mice but not when Tgs were reconstituted with WT BM, in which injury was followed by slowly progressive neointimal expansion. Injection of CD34+ cells from Tg mice into injured WT mice resulted in the accumulation of fusion protein-expressing cells from day 3 onwards and an absence of neointimal hyperplasia in those areas. Conclusions:,Neointimal development after wire-induced endovascular injury in mice was completely inhibited when BM-derived cells infiltrating the damaged artery expressed membrane tethered anticoagulant fusion proteins under an , -SMA promoter. These findings enhance our understanding of the pathological role that coagulation proteins play in vascular inflammation. [source] Tissue factor pathway inhibitor revisitedJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2004L. VIJAYA MOHNA RAO [source] Tissue factor pathway inhibitor revisitedJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2004A. MAST [source] Antibodies to tissue factor pathway inhibitor are uncommonly detected in patients with infection-related antiphospholipid antibodiesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2003R. R. Forastiero No abstract is available for this article. [source] The rediscovery and isolation of TFPIJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2003G. J. Broze Jr Summary., Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type proteinase inhibitor that produces factor (F)Xa-dependent feedback inhibition of the factor VIIa/tissue factor (FVIIa/TF) catalytic complex that is responsible for the initiation of coagulation. Since 1985, when Rapaport and colleagues reported that the lipoprotein fraction of plasma contained a FXa-dependent inhibitor of FVIIa/TF, myriad articles have established its biochemical structure, its mechanism of action, and its physiological importance. This brief personal account reviews historical studies that established the existence of the inhibitor and the events that led to its initial isolation. [source] Poor anticoagulant response to tissue factor pathway inhibitor in patients with venous thrombosisJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2003B. Tardy-Poncet Summary., Tissue factor pathway inhibitor (TFPI) is of major importance in regulating the coagulation triggering effects of tissue factor. An association between TFPI deficiency and thrombosis has still not been clearly demonstrated. We evaluated the anticoagulant activity of exogenous TFPI added either to the plasma of patients with venous thrombosis (n = 118) or to the plasma of healthy controls similar in terms of mean age and sex ratio (n = 107). A poor anticoagulant response to TFPI, defined as TFPI resistance, was observed in 4.7% of controls and in 11.0% of patients. TFPI resistance was associated with an almost threefold increase in the risk of thrombosis and could therefore represent a novel hemostatic risk factor for venous thrombosis. [source] Modulation of endothelial cell inflammatory integrins and stress markers with rh-factor VIIa in patients with advanced chronic hepatitis CJOURNAL OF VIRAL HEPATITIS, Issue 4 2003D. H. Van Thiel Summary. Individuals with chronic hepatitis C (CHC) progress to cirrhosis and hepatic cancer. Individuals with advanced CHC are coagulopathic and can manifest fibrinolysis. The coagulopathy is a consequence of hepatocytic dysfunction. The fibrinolysis represents a response to local endothelial cell injury, and is of a low-grade. Based upon this hypothesis, the effect of the infusion of recombinant human factor VIIa (rh-FVIIa) on endothelial cell inflammatory integrins and measures of endothelial stress were determined in 17 individuals with advanced CHC. Immediately prior to the infusion of rh-FVIIa, the plasma levels of tissue factor (TF), Thrombomodulin (TM), human soluble ICAM-1 (hs-ICAM-1), human soluble VCAM-1 (hs-VCAM-1), human soluble L-Selectin (hs-L-Selectin), the prothrombin time and the activated partial thromboplastin time were determined. The same parameters were assayed at 5, 10, 30, 120, 240 and 360 min after infusion. TF and TM levels were very high at baseline consistent with a vascular endothelial stress response. Similarly hs-ICAM-1, hs-VCAM-1 as well as L-Selectin levels were increased. Thirty minutes after the infusion, a marked reduction in ICAM-1 and VCAM-1 and to a lesser degree L-Selectin levels was observed. This reduction persisted for 360 min. No change in measures of fibrinolysis [plasminogen activator inhibitor-1 (PAI-1), total tissue factor pathway inhibitor (t-TFPI), activated tissue factor pathway inhibitor (TFPIa), d-dimers (DD), FSP and fibrinogen levels] occurred. In addition, no change in plasma Annexin-V was observed. Based upon these data it can be concluded that: (1) rh-FVIIa corrects the coagulopathy seen in advanced CHC; (2) reduces endothelial cell injury and/or stress as evidenced by the TF, TM, hs-ICAM-1 and hs-VCAM-1 levels in plasma; (3) these changes in coagulation occurred without inducing a propagated vascular thrombosis. [source] Aldosterone induces collagen synthesis via activation of extracellular signal-regulated kinase 1 and 2 in renal proximal tubulesNEPHROLOGY, Issue 8 2008GUOSHUANG XU SUMMARY: Aim: Aldosterone plays a crucial role in renal fibrosis by inducing mesangial cell proliferation and promoting collagen synthesis in renal fibroblasts. However, renal proximal tubule involvement in aldosterone-induced collagen synthesis has not yet been identified. The aim of this study was to examine the potential role of aldosterone in collagen expression and its possible mineralocorticoid receptor (MR)-dependent pathway, mediated by activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) in cultured human renal proximal tubular epithelial (HKC) cells. Methods: After HKC cells were stimulated by aldosterone with different concentrations for various time and periods, the gene expression and protein synthesis of collagen I, II, III and IV were measured by real-time polymerase chain reaction and western blot, respectively. ERK1/2 activation, ,-smooth muscle actin (,-SMA), and E-cadherin were also detected by western blot. Results: Aldosterone can increase ERK1/2 phosphorylation of human renal proximal tubular epithelial cells in a time- and dose-dependent manner. Although aldosterone had no effect on collagen I and II expression, it increased expression of ,-SMA and collagen III and IV and decreased that of E-cadherin in HKC cells after 48 h. These effects could be prevented by a ERK pathway inhibitor, U0126, or by a selective MR antagonist, spironolactone. Conclusion: The results suggest that aldosterone plays a pivotal role in tubulointerstitial fibrosis by promoting tubular epithelial,mesenchymal transition and collagen synthesis in proximal tubular cells. The process is MR-dependent, and mediated by ERK1/2 mitogen-activated protein kinase pathway. [source] Venous thrombosis associated with gene deletion of tissue factor pathway inhibitor,AMERICAN JOURNAL OF HEMATOLOGY, Issue 11 2009Alex Kentsis No abstract is available for this article. [source] Absence of hypercoagulability in acute Kawasaki diseasePEDIATRICS INTERNATIONAL, Issue 2 2005Ming-Tsan Lin AbstractBackground:,Kawasaki disease (KD) is a systemic vasculitis syndrome with the striking feature of cardiovascular involvement. Endothelial cell (EC) damage has been suggested to predispose individuals to the development of coronary vascular disorders. When EC are perturbed, prethrombotic complications ensue. The purpose of this study was to examine the clinical relevance of EC activation and hypercoagulability in the pathogenesis of KD and to determine if plasma levels of these markers are correlated with the development of coronary aneurysms. Methods:,EC function and coagulation status were assessed in 52 patients with acute KD, 20 febrile control subjects, and 20 healthy control subjects. Biological markers of EC and hypercoagulability were measured and included thrombomodulin, tissue factor, tissue factor pathway inhibitor, von Willebrand factor (vWF), coagulation factor VII (FVII), activated factor VII, prothrombin fragment 1 + 2 (F1 + 2), and D-dimer. Results:,Transient dilatation of coronary arteries was the most common complication (55.8%), and coronary aneurysm was noted in five patients (9.6%). Levels of vWF, FVII, F1 + 2 and D-dimer were higher in acute KD patients compared with healthy controls but not febrile controls. Markers of EC and hypercoagulability were not different between patients with cardiac complications and those without cardiac complications. Biological and immunological assays did not demonstrate the prethrombotic state in acute KD. Conclusions:,Our results suggest that hypercoagulability does not occur during the acute stage of KD. Markers of EC damage and hypercoagulability are not predictive of coronary aneurysms in KD. [source] Tissue factor and tissue factor pathway inhibitorANAESTHESIA, Issue 5 2004G. C. Price Summary The classical ,cascade/waterfall' hypothesis formulated to explain in vitro coagulation organised the amplification processes into the intrinsic and extrinsic pathways. Recent molecular biology and clinical data indicate that tissue factor/factor-VII interaction is the primary cellular initiator of coagulation in vivo. The process of blood coagulation is divided into an initiation phase followed by a propagation phase. The discovery of tissue factor pathway inhibitor further supports the revised theory of coagulation. Tissue factor is also a signalling receptor. Recent evidence has shown that blood-borne tissue factor has an important procoagulant function in sepsis, atherosclerosis and cancer, and other functions beyond haemostasis such as immune function and metastases. [source] Quantification of heparin-induced TFPI release: a maximum release at low heparin doseBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 6 2002Michiel J. B. Kemme Aims Heparin releases tissue factor pathway inhibitor (TFPI) from the endothelium and this release may decrease after repeated high dose heparin administration. The primary aim was to investigate and quantify this phenomenon during a short low dose heparin infusion. Also, the effects of heparin on tissue plasminogen activator (t-PA) were studied. Methods Nine healthy, nonsmoking, male volunteers (range 19,23 years) received a continuous heparin infusion (2000 IU) over 40 min. The endothelial TFPI release rate was estimated from the total TFPI concentration profile using a pharmacokinetic model. Results , Mean ,±,s.d. ,total ,and ,free ,TFPI ,increased ,from ,62.9 ± 9.4/8.3 ± 2.1 ng ml,1 at baseline to 237.2 ± 40.9/111.0 ± 19.9 ng ml,1 after 40 min infusion. The relationship between heparin concentration (anti-IIa activity) and TFPI concentration followed a maximum effect model and a clockwise loop (proteresis) was observed. The TFPI release rate rapidly increased to maximum of 200 ± 45 µg min,1 after 17.5 min heparin infusion but did not increase further although heparin concentrations further doubled. In contrast to TFPI, t-PA antigen decreased from 5.6 ± 1.0 at baseline to 4.5 ± 1.0 ng ml,1 at the end of infusion (t = 40 min) (difference of 1.1 ng ml,1 (95% confidence interval; 0.9, 1.3). Conclusions Our application of concentration-effect models and pharmacokinetic principles to these haemostatic variables showed that endothelial TFPI release has a maximum that is already reached at low heparin dose, corresponding with an anti-IIa activity of 0.08 IU ml,1. The relationship between anti-IIa activity and TFPI release rate showed signs of acute tolerance (clockwise loop) indicating exhaustion of endothelial TFPI pools. These findings may be of importance for the heparin dose used in conditions such as unstable angina, in which the favourable effects of heparin have been ascribed to its ability to release TFPI. [source] Expression analysis of chick Wnt and frizzled genes and selected inhibitors in early chick patterningDEVELOPMENTAL DYNAMICS, Issue 3 2004Susan C. Chapman Abstract Wnt signaling is an important component in patterning the early embryo and specifically the neural plate. Studies in Xenopus, mouse, and zebrafish have shown that signaling by members of the Wnt family of secreted signaling factors, their Frizzled receptors and several inhibitors (sFRP1, sFRP2, sFRP3/Frzb1, Crescent/Frzb2, Dkk1, and Cerberus) are involved. However, very little is known about the expression of genes in the Wnt signaling pathway during early anterior neural patterning in chick. We have performed an expression analysis at neural plate stages of several Wnts, Frizzled genes, and Wnt signaling pathway inhibitors using in situ hybridization. The gene expression patterns of these markers are extremely dynamic. We have identified two candidate molecules for anterior patterning of the neural plate, Wnt1 and Wnt8b, which are expressed in the rostral ectoderm at these stages. Further functional studies on the roles of these markers are underway. Developmental Dynamics 229:668,676, 2004. © 2004 Wiley-Liss, Inc. [source] Progestin upregulates G-protein-coupled receptor 30 in breast cancer cellsFEBS JOURNAL, Issue 10 2002Tytti M. Ahola A differential display method was used to study genes the expression of which is altered during growth inhibition induced by medroxyprogesterone acetate (MPA). A transcript of G-protein-coupled receptor 30 (GPR30) was upregulated by MPA in estrogen-treated MCF-7 breast cancer cells. Northern-blot analysis showed a progestin-specific primary target gene, which was enhanced by progesterone and different progestins, but not by dihydrotestosterone or dexamethasone, and which was abrogated by antiprogestin RU486. The dose-dependent and time-dependent increase in GPR30 mRNA expression correlated with MPA-induced growth inhibition in MCF-7 cells. Additionally, GPR30 upregulation by progestin correlated with growth inhibition when a comparison was made between different breast cancer cell lines. The ERK1/ERK2 pathway is capable of inducing progesterone receptor-dependent and ligand-dependent transcription. Thus we sought to establish whether different MAPK pathway inhibitors affect progestin-induced GPR30 mRNA regulation. The regulation of GPR30 was independent of ERK pathway activation, but the p38 pathway inhibitor induced GPR30 expression, which suggested a potential gene regulation pathway. These data demonstrate a new progestin target gene, the expression of which correlates with growth inhibition. [source] | ||||||||||||||||