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Chu AJ. Tissue factor upregulation drives a thrombosis-inflammation circuit in relation to cardiovascular complications. Cell Biochem Funct 2006; 24:173-92. [PMID: 15617024 DOI: 10.1002/cbf.1200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The extrinsic coagulation is recognized as an 'inducible' signalling cascade resulting from tissue factor (TF) upregulation by exposure to clotting zymogen FVII upon inflammation or tissue injury. Following the substantial initiation, an array of proteolytic activation generates mediating signals (active serine proteases: FVIIa, FXa and FIIa) that lead to hypercoagulation with fibrin overproduction manifesting thrombosis. In addition, TF upregulation plays a central role in driving a thrombosis-inflammation circuit. Coagulant mediators (FVIIa, FXa and FIIa) and endproduct (fibrin) are proinflammatory, eliciting tissue necrosis factor, interleukins, adhesion molecules and many other intracellular signals in different cell types. Such resulting inflammation could ensure 'fibrin' thrombosis via feedback upregulation of TF. Alternatively, the resulting inflammation triggers platelet/leukocyte/polymononuclear cell activation thus contributing to 'cellular' thrombosis. TF is very vulnerable to upregulation resulting in hypercoagulability and subsequent thrombosis and inflammation, either of which presents cardiovascular risks. The prevention and intervention of TF hypercoagulability are of importance in cardioprotection. Blockade of inflammation reception and its intracellular signalling prevents TF expression from upregulation. Natural (activated protein C, tissue factor pathway inhibitor, or antithrombin III) or pharmacological anticoagulants readily offset the extrinsic hypercoagulation mainly through FVIIa, FXa or FIIa inhibition. Therefore, anticoagulants turn off the thrombosis-inflammation circuit, offering not only antithrombotic but anti-inflammatory significance in the prevention of cardiovascular complications.
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Affiliation(s)
- Arthur J Chu
- Surgery Department, Wayne State University, Detroit, MI 48201, USA.
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Chu AJ. Tissue factor mediates inflammation. Arch Biochem Biophys 2005; 440:123-32. [PMID: 16036212 DOI: 10.1016/j.abb.2005.06.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Accepted: 06/10/2005] [Indexed: 02/06/2023]
Abstract
The role of tissue factor (TF) in inflammation is mediated by blood coagulation. TF initiates the extrinsic blood coagulation that proceeds as an extracellular signaling cascade by a series of active serine proteases: FVIIa, FXa, and thrombin (FIIa) for fibrin clot production in the presence of phospholipids and Ca2+. TF upregulation resulting from its enhanced exposure to clotting factor FVII/FVIIa often manifests not only hypercoagulable but also inflammatory state. Coagulant mediators (FVIIa, FXa, and FIIa) are proinflammatory, which are largely transmitted by protease-activated receptors (PAR) to elicit inflammation including the expression of tissue necrosis factor, interleukins, adhesion molecules (MCP-1, ICAM-1, VCAM-1, selectins, etc.), and growth factors (VEGF, PDGF, bFGF, etc.). In addition, fibrin, and its fragments are also able to promote inflammation. In the event of TF hypercoagulability accompanied by the elevations in clotting signals including fibrin overproduction, the inflammatory consequence could be enormous. Antagonism to coagulation-dependent inflammation includes (1) TF downregulation, (2) anti-coagulation, and (3) PAR blockade. TF downregulation and anti-coagulation prevent and limit the proceeding of coagulation cascade in the generation of proinflammatory coagulant signals, while PAR antagonists block the transmission of such signals. These approaches are of significance in interrupting the coagulation-inflammation cycle in contribution to not only anti-inflammation but also anti-thrombosis for cardioprotection.
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Affiliation(s)
- Arthur J Chu
- MRC, Shantou University, Shantou, Guangdong 515063, PR China.
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Chu AJ, Rauci M, Nwobi OI, Mathews ST, Beydoun S. Novel anticoagulant activity of polyamino acid offsets bacterial endotoxin-induced extrinsic hypercoagulation: downregulation of monocytic tissue factor-dependent FVII activation. J Cardiovasc Pharmacol 2004; 42:477-83. [PMID: 14508232 DOI: 10.1097/00005344-200310000-00004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The extrinsic hypercoagulation often resulting from sepsis could contribute to disseminated intravascular coagulation and cardiovascular complications. The effective prevention and intervention remained largely complex and unclear. In a cell model of human leukemia THP-1 monocytes following bacterial endotoxin (LPS) exposure, we show the novel anticoagulant ability of polyamino acid (polyAA) to suppress the extrinsic hypercoagulation. LPS-induced monocytic tissue factor (mTF) procoagulation was readily offset by poly-L-lysine (PLK), poly-L-arginine (PLR), or poly-L-ornithine (POR) included in single-stage clotting assays. IC50 was estimated at 0.35, 0.30, or 0.58 microM for PLR, POR, or PLK, respectively, whereas, poly-L-asparatic acid (PLD) remained ineffective. In a separate approach, inclusion of cationic polyAA in human plasma significantly prolonged prothrombin time, confirming the depressed extrinsic coagulation. In chromogenic assays dissecting the extrinsic pathway, we further determined the inhibitory site(s). PLK, PLR, or POR significantly inhibited LPS-induced FVII activation, which was consistent with the diminished FVIIa formation shown on Western blotting analysis. In contrast, polyAA did not show any additional effect on either FVIIa/FXa amidolytic activities or mTF/FVIIa-catalyzed FX activation. Nor did polyAA show any effect on FVII activation directly catalyzed by FXa. Taken together, PLK, PLR, or POR preferentially inhibited mTF-dependent FVII activation, accounting for their novel anticoagulant activities. PolyAA might present the specific antagonists to arrest the extrinsic hypercoagulation following inflammation.
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Affiliation(s)
- Arthur J Chu
- Department of Surgery, School of Medicine, Wayne State University, Detroit, Michigan, USA.
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Abstract
BACKGROUND Hypercoagulability often resulting from sepsis, trauma, and other conditions is widely associated with thrombotic and cardiovascular disorders. The development of effective and safe anticoagulation is in great demand to relieve complications and improve human health. OBJECTIVE We study the anticoagulant potential of a polyclonal antibody to human FVII (anti-hFVII Ab). METHODS AND RESULTS Preincubating FVII with anti-hFVII Ab, we showed the significantly blocked tissue factor (TF)-dependent FVII activation monitored by a two-stage chromogenic assay. Consistently, the antibody depressed TF/FVII-catalyzed FX activation was shown on Western blotting analysis. As a result, TF procoagulation derived from rabbit brain thromboplastin was prolonged significantly by the preincubation of human normal plasma with the antibody, which mimicked FVII-deficient plasma in a single-stage clotting assay. In contrast, the anti-hFVII Ab had no effect on either FVIIa amidolytic activity or TF/FVIIa binary complex. CONCLUSIONS Anti-hFVII Ab readily blocked clot formation, which was mediated by the upstream downregulation of the extrinsic coagulation of inhibiting FVII activation. Further research warrants establishing its in vivo application as an anticoagulant.
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Affiliation(s)
- Arthur J Chu
- Department of Surgery, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
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Chu AJ, Beydoun S, Mathews ST, Hoang J. Novel anticoagulant polyethylenimine: inhibition of thrombin-catalyzed fibrin formation. Arch Biochem Biophys 2003; 415:101-8. [PMID: 12801518 DOI: 10.1016/s0003-9861(03)00216-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Hypercoagulability is often associated with a variety of disease states, leading to cardiovascular complications. Polyethylenimine (PEI) prolonged prothrombin time, demonstrating its anticoagulant potential. In vitro, PEI at low concentration (nM) significantly blocked thrombin-catalyzed fibrin formation, accounting for its mode of anticoagulation. The uncompetitive inhibition by PEI of fibrin formation was independent of the concentration of fibrinogen (FBG), thrombin, or NaCl. PEI showed no effect on thrombin amidolytic activity, suggesting that the blockade of thrombin interaction with FBG could account for the inhibition on fibrin formation. PEI drastically depressed rabbit brain thromboplastin procoagulation monitored by a single-stage clotting assay using human plasma. In a THP-1 monocytic hypercoagulation model, a 4-h exposure to bacterial endotoxin or Ca(2+) ionophore A23187, respectively, resulted in a 5- or 10-fold enhancement in monocytic tissue factor (mTF) procoagulation. mTF hypercoagulation was offset by PEI included in the assay mixture. PEI showed the potential to arrest mTF hypercoagulation with IC(50) around 1.2 nM. Using a chromogenic assay to dissect the extrinsic pathway, we further assessed whether PEI has any effect on other clotting factors. PEI was not an inhibitor for either FVIIa or FXa, having no effect on not only the amidolytic but also their corresponding functionally catalytic activities. Although PEI upregulated TF-dependent FVII activation under the low-salt condition, the effective downstream inhibition of fibrin formation readily abolished and overrode the upstream enhancement, demonstrating the overall anticoagulation. PEI could present a new class of anticoagulant.
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Affiliation(s)
- Arthur J Chu
- Department of Surgery, School of Medicine, University Health Center, Wayne State University, Detroit, MI 48201, USA.
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Chu AJ, Lin SH, Piasentin E. Possible role of Marcks in the cellular modulation of monocytic tissue factor-initiated hypercoagulation. Br J Haematol 2002; 118:569-76. [PMID: 12139748 DOI: 10.1046/j.1365-2141.2002.03611.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The enhanced extrinsic tissue factor (TF)-initiated coagulation, often resulting from sepsis, could lead to disseminated intravascular coagulation presenting cardiovascular complications. Using model human leukaemia THP-1 monocytes, we studied monocytic TF (mTF) hypercoagulation and its regulation. After an 8 h exposure to bacterial endotoxin [lipopolysaccharide (LPS); 100 ng/ml], mTF activity was significantly upregulated as the result of the enhanced mTF synthesis. Thereafter, LPS induction declined, exhibiting a "quiescent-desensitizing' phenomenon. Such diminished LPS induction was,however,associated with sustained LPS-enhanced mTF synthesis, revealing the possible occurrence of a post-translational downregulation. It was noted that LPS desensitization was accompanied by the increased expression of myristoylated alanine-rich C kinase substrate (Marcks). In contrast, A23187 (20 micromol/l) or Quin-2AM (20 micromol/l) drastically activated mTF activity without detectable effect on mTF synthesis; both of which showed that sustained functional upregulation during 24 h culture did not enhance Marcks expression. These inverse correlations between mTF activity upregulation and Marcks expression suggested that Marcks could be inhibitory. Marcks phosphorylation site domain (151-175) (Marcks PSD) readily inhibited mTF-dependent FVII activation and diminished FVIIa formation in LPS-challenged cells. As a result, Marcks PSD offset LPS-induced mTF hypercoagulation upon inclusion in the single-stage clotting assays. The anticoagulant activity was confirmed by showing that Marcks PSD significantly blocked rabbit brain thromboplastin (rbTF) procoagulation and inhibited rbTF-dependent FVII activation as well as FVIIa formation. Our study suggests that Marcks expression plays a role in a novel cellular modulation to downregulate mTF hypercoagulation.
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Affiliation(s)
- Arthur J Chu
- Department of Surgery, School of Medicine, Wayne State University, 416 Lande Medical Research Building, 550 E. Canfield, Detroit, MI 48201, USA.
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Chu AJ, Rauci M, Nwobi OI, Mathews ST, Beydoun S. Novel anticoagulant activity of polybrene: inhibition of monocytic tissue factor hypercoagulation following bacterial endotoxin induction. Blood Coagul Fibrinolysis 2002; 13:123-8. [PMID: 11914654 DOI: 10.1097/00001721-200203000-00007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The enhanced extrinsic coagulation in response to inflammation could contribute to disseminated intravascular coagulation, often manifesting cardiovascular complications. The complex mechanism remains unclear. Nor is the effective anticoagulation well established. The search for arresting hypercoagulation is of antithrombotic relevance. The ability of polybrene (PB) to inhibit tissue factor (TF)-initiated extrinsic blood coagulation was demonstrated at the protein and cellular levels as well as in human plasma samples. In a single-stage clotting assay, PB dose-dependently offset bacterial endotoxin (lipopolysaccharide)-induced monocytic TF (mTF) hypercoagulation and inhibited rabbit brain thromboplastin (rbTF) procoagulation. Consistent with these findings, the significantly prolonged prothrombin time indicated the depressed extrinsic coagulation by PB. However, PB showed no effect on thrombin time. We dissected the extrinsic pathway to further determine the inhibitory site(s) of PB. A two-stage chromogenic assay monitoring S-2288 hydrolysis showed that PB readily blocked mTF-dependent or rbTF-dependent FVII activation, which was verified by the diminished activated factor VII (FVIIa) formation derived from the proteolytic cleavage of its zymogen factor VII on Western blotting analyses. PB had no effect on FVIIa and activated factor X amidolytic activity. Nor was the dissected TF/FVIIa-catalyzed factor X activation affected. In conclusion, the preferential downregulation of factor VII activation was responsible for the depressed extrinsic coagulation. PB could present a novel anticoagulant antagonizing the extrinsic hypercoagulation for the prevention of thrombotic complication following sepsis and inflammations.
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Affiliation(s)
- A J Chu
- Department of Surgery, School of Medicine, Wayne State University, Detroit, Michigan, USA.
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Chu AJ, Wang ZG, Raicu M, Beydoun S, Ramos N. Protamine inhibits tissue factor-initiated extrinsic coagulation. Br J Haematol 2001; 115:392-9. [PMID: 11703341 DOI: 10.1046/j.1365-2141.2001.03100.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The enhanced extrinsic coagulation in response to inflammation could contribute to disseminated intravascular coagulation, often manifesting cardiovascular complications. The complex mechanism remains unclear and effective management is not well established. The ability of protamine to offset bacterial endotoxin (LPS)-induced tissue factor (TF)-initiated extrinsic coagulation was demonstrated in human peripheral blood monocytes and cultured human leukaemia THP-1 monocytes, which was consistent with the inhibition of rabbit brain thromboplastin (rbTF) procoagulant activity in a cell-free in vitro model. Protamine significantly prolonged prothrombin time, further confirming the downregulation of the extrinsic pathway. However, thrombin time remained unaltered. Chromogenic assays were performed to dissect the extrinsic pathway, identifying inhibitory site(s). Protamine significantly inhibited factor VII (FVII) activation but not the dissected FX activation. The amidolytic activities of FVIIa and FXa were unaffected. The inhibited FVII activation in the presence of protamine was confirmed by the diminished FVIIa formation on Western blot analyses. Protamine preferentially inhibited TF-catalysed FVII activation, downregulating the extrinsic cascade. Protamine could be of anticoagulant significance in the management of the extrinsic hypercoagulation.
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Affiliation(s)
- A J Chu
- Department of Surgery, School of Medicine, Wayne State University, Detroit, MI, USA.
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Chu AJ, Chen BM, Lin H, Beydoun S. Antimicrobial peptide buforin I inhibits tissue factor-initiated coagulation. Arch Biochem Biophys 2001; 392:3-7. [PMID: 11469787 DOI: 10.1006/abbi.2001.2444] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The enhanced extrinsic blood coagulation following septic shock often manifests cardiovascular complications. The upregulated monocytic tissue factor (mTF) was shown to be a primary contributor to the extrinsic hypercoagulation following acute bacterial endotoxin (LPS) infection. A single-stage clotting assay monitors TF-initiated coagulation. We herein demonstrate a novel anticoagulant activity of antimicrobial peptide Buforin I (BF I) in offsetting LPS-induced mTF hypercoagulation in THP-1 cells, which was confirmed in a cell-free in vitro model, showing that BF I effectively blocked rabbit brain thromboplastin (rbTF) procoagulant activity. Upon inclusion of 25 microM BF I into human plasma, the prolonged prothrombin time (PT) was consistent with the depressed TF-initiated coagulation. In a two-stage chromogenic assay monitoring S-2288 hydrolysis, BF I significantly inhibited not only mTF- but also rbTF-catalyzed FVII activation accompanied by the diminished FVIIa formation. The inhibition by BF I of FVII activation accounted for its novel anticoagulant activity in offsetting mTF-initiated hypercoagulation.
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Affiliation(s)
- A J Chu
- Department of Surgery, School of Medicine, Wayne State University, Detroit, Michigan 48201, USA.
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Chu AJ, Wang ZG, Nwobi OI, Beydoun S. Blockade by ruthenium red of tissue factor-initiated coagulation. Br J Pharmacol 2001; 133:659-64. [PMID: 11429389 PMCID: PMC1572830 DOI: 10.1038/sj.bjp.0704116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The ability of ruthenium red (RuR) to inhibit tissue factor (TF)-initiated blood coagulation was demonstrated at the protein and cellular levels as well as in human plasma. In a single-stage clotting assay, RuR concentration-dependently inhibited rabbit brain thromboplastin (rbTF)-induced coagulation and offset bacterial endotoxin (LPS)-induced monocytic TF (mTF) hypercoagulation; the IC(50)s were estimated at 7.5 and 12.3 microM, respectively. A 15-min preincubation of RuR with rbTF or monocyte suspension resulted in the pronounced inhibition with a significantly lowered IC(50) at 1.8 or 7.7 microM for rbTF or mTF procoagulation, respectively. The differences in IC(50)s between rbTF and mTF without or with the preincubation indicated that TF was a primary target for RuR action. The effect of RuR on the physiological function of TF in FVII activation was demonstrated by the proteolytic cleavage of FVII zymogen to its active forms of serine protease on Western blotting analyses. RuR readily blocked TF-catalyzed FVII activation (diminished FVIIa formation), thus down regulating the initiation of blood coagulation. Inclusion of RuR into human plasma samples in vitro significantly prolonged prothrombin time, indicating the depressed coagulation. FVII activity was inhibited by 30 - 60% depending on the dose; as a result, FX activity also decreased. However, RuR showed no effect on thrombin time. Thus, RuR inhibited FVII activation to block the initiation of coagulation.
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Affiliation(s)
- A J Chu
- Department of Surgery, School of Medicine, Wayne State University, USA.
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