Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have recently shown that endothelial cell-derived IL-8 inhibits neutrophil adhesion to IL1-beta-activated human umbilical vein endothelial cell monolayers. IL-8 secreted by T lymphocytes or monocytes has been characterized as a promoter of neutrophil degranulation and chemotaxis. The IL-8 isolated from each of these cell types is a mixture of two IL-8 polypeptides, one consisting of 72 amino acids (herein called [ser-IL-8]72) and the other 77 amino acids (an N-terminal extended form herein called [ala-IL-8]77). IL-8 derived from T lymphocytes and monocytes is predominantly [ser-IL-8]72, whereas endothelial-derived IL-8 is highly enriched (greater than 80%) in [ala-IL-8]77. We address the relationship and activities of these two forms of IL-8 using recombinant proteins expressed by both mammalian cells and Escherichia coli. Thrombin was found to efficiently convert [ala-IL-8]77 to [ser-IL-8]72. In contrast, urokinase and tissue-type plasminogen activator were unable to cleave [ala-IL-8]77, and trypsin generated multiple IL-8 cleavage fragments. In competitive binding assays using 125I[ala-IL-8]77 neutrophils exhibited a twofold preference for [ser-IL-8]72 over [ala-IL-8]77. Both forms of IL-8 inhibited neutrophil adhesion to IL-1-beta-activated HUVEC monolayers by up to 90%. However, [ser-IL-8]72 was approximately 10-fold more potent than [ala-IL-8]77 in these assays (ED50 approximately 0.3 nM for [ser-IL-8]72 vs approximately 3 nM for [ala-IL-8]77. Both forms of IL-8 promoted degranulation of cytochalasin B-treated neutrophils [[ser-IL-8]72 (ED50 greater than 10 nM) was two- to three-fold more potent than [ala-IL-8]77], although in this regard they were less active than FMLP. Our data suggest that [ala-IL-8]77 and [ser-IL-8]72 have qualitatively similar and potentially complex biological activities, and that full activation of IL-8 requires cleavage to the [ser-IL-8]72 form. In the case of inflamed endothelial cells this activation could be mediated by thrombin generated in the procoagulant environment associated with these cells.
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PMID:Endothelial and leukocyte forms of IL-8. Conversion by thrombin and interactions with neutrophils. 221 72

IL-10 protects mice from LPS-induced lethality. To determine the effects of IL-10 on LPS-induced inflammatory responses, six Papio anubis baboons were i.v. injected with a sublethal dose of LPS (Salmonella typhimurium; 500 microg/kg) directly preceded by either human rIL-10 (n = 3, 500 microg/kg) or diluent (n = 3). IL-10 strongly inhibited LPS-induced release of TNF, IL-6, IL-8, and IL-12 (all p < 0.05). By contrast, IL-10 did neither influence the activation of the coagulation system (plasma levels of thrombin/antithrombin III complexes), nor the activation of the fibrinolytic system (plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor type I, and plasmin/alpha 2-antiplasmin complexes). IL-10 modestly attenuated neutrophilic leukocytosis and neutrophil degranulation (plasma concentrations of elastase/alpha1-antitrypsin complexes) (both p < 0.05). Changes in surface TNF receptor expression on circulating granulocytes were not affected by IL-10. These results suggest that during sublethal endotoxemia the predominant anti-inflammatory effect of IL-10 treatment is inhibition of proinflammatory cytokine release.
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PMID:Effects of IL-10 on systemic inflammatory responses during sublethal primate endotoxemia. 902 40

Inflammatory response in tissue results from a complex network of interactions between inflammatory cells (mast cells, eosinophils, basophils, macrophages) and resident cells belonging to the lung structure (like endothelial cells, fibroblasts, epithelial cells). Among structural cells, endothelial cells play a critical role. The important role of endothelium is also reflected in the fact that it occupies an area exceeding 1000 m2. Thus, endothelium is the largest and the most active paracrine organ in the body, producing potent vasoactive, procoagulant, anticoagulant, and proinflammatory substances. Endothelial cells have four key functions that alter in the process of inflammation: 1 a) Regulation and control of leukocyte traffic through the expression of adhesion molecules (selectins E and P, molecules of immunoglobulin superfamily ICAM-1, ICAM-2, VCAM); 1 b) They are also able to amplify leukocyte activation through the production of proinflammatory cytokines like IL-1, IL-6 and chemokines like IL-8 and RANTES molecules; 2) Regulation of vascular tone by production of PGI-2, EDRF/NO and elements of local renin-angiotensin system; 3) Regulation of local coagulation by controlling the production of t-PA and PAI-1; 4) Regulation of the vascular permeability. In the states of acute inflammation, the endothelial cell takes on a proinflammatory phenotype and as such becomes chemoattractant, facilitating leukocyte adhesion, activation and migration, becomes prothrombotic and demonstrates enhanced vascular permeability.
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PMID:[The role of endothelial cells in allergic inflammation reactions]. 986 70

To determine in vivo effects of interleukin (IL)-12 on host inflammatory mediator systems, 4 healthy chimpanzees received recombinant human IL-12 (1 microg/kg) by intravenous injection. IL-12 induced increases in plasma concentrations of IL-15, IL-18, and interferon-gamma (IFN-gamma), plus a marked antiinflammatory cytokine response (IL-10, soluble tumor necrosis factor [TNF] receptors, IL-1 receptor antagonist) and secretion of alpha-chemokines (IL-8, IFN-gamma-inducible protein 10) and beta-chemokines (monocyte chemoattractant protein-1, macrophage inflammatory protein-1beta). In addition, IL-12 elicited neutrophilic leukocytosis, neutrophil degranulation (elastase-alpha1-antitrypsin complexes), coagulation activation (F1 + 2 prothrombin fragment, thrombin-antithrombin III complexes), and fibrinolytic activation (tissue-type plasminogen activator, plasmin-alpha2-antiplasmin complexes). IL-12-induced activation of multiple host mediator systems was found only after 8-24 h, remained detectable until the end of the 48-h observation period, and occurred in the absence of detectable TNF and IL-1beta. These data may contribute to understanding the role of IL-12 in the pathogenesis of sepsis syndrome and the toxicity found after repeated injections of IL-12.
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PMID:Interleukin-12 induces sustained activation of multiple host inflammatory mediator systems in chimpanzees. 995 71

Nitrogen dioxide (NO2) is a common indoor air pollutant, especially in homes with unvented combustion appliances. Epidemiological studies suggest that children living in homes with unvented heating sources are more prone to respiratory infections than children living in homes with lower levels of NO2. However, experimental studies in which human volunteers were exposed acutely to moderate levels of NO2 (0.5-2.0 ppm) have shown little evidence of lung inflammation or decreased host resistance capacity. In the study reported here, 8 healthy volunteers were exposed to 2.0 ppm NO2 and to filtered air for 4 h while undergoing intermittent moderate exercise. Bronchoalveolar lavage was performed the following morning. The lavage was divided into a predominantly bronchial washing (first 20 ml of lavage; BL) and a predominantly alveolar washing (BAL). In the BL, NO2 exposure caused increases in polymorphonuclear neutrophils (PMNs), interleukin 6 (IL-6), IL-8, alpha1-antitrypsin, and tissue plasminogen activator, and decreases in epithelial cells. In the BAL, there were no NO2-induced changes in either cell numbers or soluble mediators. On the other hand, alveolar macrophages from BAL showed a decrease in the ability to phagocytose unopsonized Candida albicans and a decrease in superoxide production. No difference in susceptibility to virus infection was found between the NO2- and air-exposed macrophages. No changes in lung function were observed, but the aerosol bolus recovery technique revealed a statistically significant (p <.05) decrease in the fraction of aerosol recovered following nitrogen dioxide exposure, which is suggestive of small obstructive changes induced by NO2.
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PMID:Inflammatory response in humans exposed to 2.0 ppm nitrogen dioxide. 1038 Jan 61

Gene therapy utilizing leukocytes is an unexplored therapeutic strategy for targeting tissue-type plasminogen activator (t-PA) to fibrin and sites of inflammation. In this study, five cationic lipids were observed to enhance the adenovirus (Ad)-mediated expression of t-PA in human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner between 1000 and 15,000 lipid molecules per Ad particle (efficiency:LipofectAMINE > GenePORTER > Effectene > SuperFect > DMRIE-C). PBMCs treated with Ad/t-PA * LipofectAMINE complexes displayed elevated t-PA expression over a 4-day period and the t-PA-expressing cells facilitated the lysis of plasma clots in vitro. Functional and immunologic assays revealed that the Ad * LipofectAMINE infection protocol did not affect monocyte adhesion in vitro or elevate the expression of procoagulant activity, interleukin 8, or tumor necrosis factor alpha. The potential of this system was documented with an in vivo rat model system that involved the injection of lipopolysaccharide into the peritoneal cavity to induce an inflammatory response. Infusion of Ad/t-PA-infected rat PBMCs into the vasculature of lipopolysaccharide-treated animals was found to increase local fibrinolytic activity by 4-fold. These data provide a framework for utilizing adenovirus to transfer genes into PBMCs.
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PMID:Modulating the fibrinolytic system of peripheral blood mononuclear cells with adenovirus. 1124 35

Systemic inflammation because of sepsis results in endothelial cell activation and microvascular injury. High-mobility group protein-1 (HMGB1), a novel inflammatory molecule, is a late mediator of endotoxin shock and is present in the blood of septic patients. The receptor for advanced glycation end products (RAGE) is expressed on endothelium and is a receptor for HMGB1. Here we examine the effects of HMGB1 on human endothelial cell function. Recombinant human HMGB1 (rhHMGB1) was cloned and expressed in Escherichia coli and incubated with human microvascular endothelium. rhHMGB1 caused a dose- and time-dependent increase in the expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and RAGE. rhHMGB1 induced the secretion of tumor necrosis factor-alpha (TNFalpha), interleukin 8 (IL-8), monocyte chemotactic protein-1 (MCP-1), plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) (P <.01). rhHMGB1 stimulation resulted in transient phosphorylation of mitogen-activated protein (MAP) kinases, extracellular signal-related kinase (ERK), Jun N-terminal kinase (JNK), and p38, and in nuclear translocation of transcription factors NF-kappaB and Sp1. These effects are partially mediated by TNFalpha autocrine stimulation, as anti-TNFalpha antibodies significantly decrease chemokine and adhesion molecule responses (P </=.002). Thus, rhHMGB1 elicits proinflammatory responses on endothelial cells and may contribute to alterations in endothelial cell function in human inflammation.
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PMID:Inflammation-promoting activity of HMGB1 on human microvascular endothelial cells. 1245 6

Recent epidemiological studies indicated risk reductions in ovarian cancer with consumption of acetaminophen or non-steroid anti-inflammatory drugs. Until now, there is not a systematic analysis, why these agents may reduce risk of ovarian cancer, as it has been performed to explain aspirin-reduction of colon cancer risk. This review tries to explain molecular mechanisms pertinent to acetaminophen- and NSAID-reduction of ovarian cancer. It is proposed that the major mechanism by these anti-inflammatory agents is a shared pathway dependent on the suppression of NF-kappaB activity, which may subsequently decrease transcription of growth factors, chemokines and proteases such as COX-2, VEGF, IL-8/CXCL8, MCP-1/CCL-2, MIP1alpha/CCL-3, tPA and uPA, which are shown to be elevated in ovarian carcinoma, and which play diverse roles such as inducing angiogenesis, invasion, autocrine growth loops and resistance to apoptosis. Besides these, specific mechanisms of action can be attributed to acetaminophen-reduction of ovarian cancer risk via I. Induction of specific reproductive atrophy due its sex-steroid resembling phenolic ring; II. Reduction of glutathione pools due to its NAPQI metabolite, which may play an important role for sterilizing pre-malignant ovarian lesions, since they are shown to lack proper levels of glutathione; III. Inhibition of tautomerization activity of MIF (macrophage migration inhibitory factor), which is shown to be released from ovarian cancer, and which is necessary for proper ovulation; IV. Inhibition of cytokine-induced and endothelia-origined cyclooxygenases. Except the chemosensitization studies, acetaminophen and NSAIDs should be investigated in animal models to test likely benefits in ovarian cancer, since most of their activity may origin from intervening with the cancer growth-stimulating inflammatory stimuli, rather than with the direct cellular toxicity.
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PMID:NF-kappaB, macrophage migration inhibitory factor and cyclooxygenase-inhibitions as likely mechanisms behind the acetaminophen- and NSAID-prevention of the ovarian cancer. 1525 53

We have recently shown that several proinflammatory chemokines can be stored in secretory granules of endothelial cells (ECs). Subsequent regulated exocytosis of such chemokines may then enable rapid recruitment of leukocytes to inflammatory sites. Although IL-8/CXCL8 and eotaxin-3/CCL26 are sorted to the rod-shaped Weibel-Palade body (WPB), we found that GROalpha/CXCL1 and MCP-1/CCL2 reside in small granules that, similarly to the WPB, respond to secretagogue stimuli. In the present study, we report that GROalpha and MCP-1 colocalized in 50- to 100-nm granules, which occur throughout the cytoplasm and at the cell cortex. Immunofluorescence confocal microscopy revealed no colocalization with multimerin or tissue plasminogen activator, i.e., proteins that are released from small granules of ECs by regulated exocytosis. Moreover, the GROalpha/MCP-1-containing granules were Rab27-negative, contrasting the Rab27-positive, WPB. The secretagogues PMA, histamine, and forskolin triggered distinct dose and time-dependent responses of GROalpha release. Furthermore, GROalpha release was more sensitive than IL-8 release to inhibitors and activators of PKA and PKC but not to an activator of Epac, a cAMP-regulated GTPase exchange factor, indicating that GROalpha release is regulated by molecular adaptors different from those regulating exocytosis of the WPB. On the basis of these findings, we designated the GROalpha/MCP-1-containing compartment the type 2 granule of regulated secretion in ECs, considering the WPB the type 1 compartment. In conclusion, we propose that the GROalpha/MCP-1-containing type 2 granule shows preferential responsiveness to important mediators of EC activation, pointing to the existence of selective agonists that would allow differential release of selected chemokines.
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PMID:Characterization of a novel chemokine-containing storage granule in endothelial cells: evidence for preferential exocytosis mediated by protein kinase A and diacylglycerol. 1621 Jun 42

The effects of steroids on the outcome of sepsis are dose dependent. Low doses appear to be beneficial, but high doses do not improve outcome for reasons that are insufficiently understood. The effects of steroids on systemic inflammation as a function of dose have not previously been studied in humans. To determine the effects of increasing doses of prednisolone on inflammation and coagulation in humans exposed to LPS, 32 healthy males received prednisolone orally at doses of 0, 3, 10, or 30 mg (n = 8 per group) at 2 h before i.v. injection of Escherichia coli LPS (4 ng/kg). Prednisolone dose-dependently inhibited the LPS-induced release of cytokines (TNF-alpha and IL-6) and chemokines (IL-8 and MCP-1), while enhancing the release of the anti-inflammatory cytokine IL-10. Prednisolone attenuated neutrophil activation (plasma elastase levels) and endothelial cell activation (von Willebrand factor). Most remarkably, prednisolone did not inhibit LPS-induced coagulation activation, measured by plasma concentrations of thrombin-antithrombin complexes, prothrombin fragment F1+2, and soluble tissue factor. In addition, activation of the fibrinolytic pathway (tissue-type plasminogen activator and plasmin-alpha(2)-antiplasmin complexes) was dose-dependently enhanced by prednisolone. These data indicate that prednisolone dose-dependently and differentially influences the systemic activation of different host response pathways during human endotoxemia.
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PMID:Prednisolone dose-dependently influences inflammation and coagulation during human endotoxemia. 1723 35


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