Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although the shock syndrome is recognized as a form of "mediator poisoning", a plethora of details is hardly converging into a coherent concept of chronological and molecular order. As a model for organ failure in septic shock, three alternative experimental approaches with a common pathology are presented: When galactosamine-sensitized mice receive either lipopolysaccharide or leukotriene D4 or tumor necrosis factor alpha they develop fulminant hepatitis within few hours with a lethal outcome within one day. Detailed pharmacological intervention studies allow to conclude that endotoxin-induced leukotriene D4 release induces a transient ischemia by the known vasoconstrictive action of this eicosanoid. A following reperfusion/reoxygenation phase gives rise to superoxide formation which inactivates alpha 1 proteinase inhibitor. Thus a serine protease becomes active which is responsible for the processing of a monocytic tumor necrosis factor alpha precursor to be released into the circulation after proteolytic cleavage. By this sequence the final central mediator of shock and sepsis becomes systematically abundant. The concept arising from these studies reconciles previously known findings and provides a link between the role of reactive oxygen species in inflammation, the balance of proteases and antiproteases in the extracellular space and the release of the cytokine tumor necrosis factor in sepsis and shock.
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PMID:Reactive oxygen species, antiproteases, and cytokines in sepsis. 179 93

To define the relationship between renal epidermal growth factor (EGF) expression and thyroid hormones in acute renal failure, we performed an analysis of the renal thyroid hormone-EGF axis following acute ischemic renal injury in rats. Levels of mature EGF extractable from kidney were elevated 24 h postinjury, and levels of membrane-associated EGF precursor were reduced. Administration of triodothyronine (T3) to rats, either prior to or immediately following the induction of injury, did not further increase levels of extractable EGF. Levels of EGF mRNA in kidneys were reduced 24 h following acute ischemic damage and not affected by administration of T3. Enhanced production of mature EGF from EGF precursor occurred in membranes isolated from kidneys of rats 24 h postinjury compared with production in membranes from kidneys of normal rats. In addition, levels of thyroxine 5'-deiodinase activity in renal membranes were increased 24 h following injury. Levels of circulating total thyroxine (T4), free T4, and free T3 were reduced postischemic injury. Total T3 was unchanged. The administration of T3 to normal rats increased renal 5'-deiodinase activity and EGF precursor cleavage. Administration of propylthiouracil to rats inhibited renal 5'-deiodinase activity and prevented the increase in extractable EGF postischemic injury. We conclude that the increase in levels of mature EGF extractable from kidneys of rats postischemic injury results from enhanced activity of the serine protease that cleaves the EGF precursor. This activity may be stimulated by T3 produced in kidney. These alterations in renal T4 metabolism and EGF expression could serve to facilitate recovery of renal function following ischemia.
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PMID:Altered EGF expression and thyroxine metabolism in kidneys following acute ischemic injury in rat. 876 19

It is well known that activation of proteases in the lysosomes and cytosol is one of the mechanisms of ischemic injury. It might thus be beneficial to determine whether the addition of several clinically available protease inhibitors to a cardioplegic solution can improve its protective ability. Using an isolated working rat heart preparation, the effects of several protease inhibitors (serine protease inhibitors; nafamostat mesilate and gabexate mesilate, a thiol-protease inhibitor; NCO-700; and a urinary trypsin inhibitor, urinastatin) on the postischemic recovery of function and enzyme leakage were investigated in this study. These protease inhibitors were added to either the cardioplegic solution or reperfusion solution. The addition of each of the protease inhibitors, except urinastatin, to the cardioplegic solution improved the postischemic recovery of function and reduced enzyme leakage. The dose-response characteristics of these three protease inhibitors were bell shaped, and the optimal concentrations of nafamostat mesilate, gabexate mesilate, and NCO-700 were 5 microM, 100 microM, and 20 microM, respectively. In contrast to the results of the preischemic treatment study, the addition of any of the protease inhibitors to the perfusion medium during Langendorff reperfusion failed to improve the postischemic recovery of function and to reduce enzyme leakage. Surprisingly, the addition of NCO-700 to the reperfusion solution at a concentration of 5 microM or higher had rather harmful effects on both functional recovery and enzyme leakage. These findings suggest that serine and thiol proteases may play an important role in myocardial injury during ischemia, but not necessarily during reperfusion.
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PMID:Effects of protease inhibitors on postischemic recovery of the heart. 935 59

Neutrophils play an important part in the development of acute inflammatory injury. Human neutrophils contain high levels of the serine protease elastase, which is stored in azurophilic granules and is secreted in response to inflammatory stimuli. Elastase is capable of degrading many components of extracellular matrix [1-4] and has cytotoxic effects on endothelial cells [5-7] and airway epithelial cells. Three types of endogenous protease inhibitors control the activity of neutrophil elastase, including alpha-1 protease inhibitor (alpha-1PI), alpha-2 macroglobulin and secreted leukoproteinase inhibitor (SLPI) [8-10]. A disturbed balance between neutrophil elastase and these inhibitors has been found in various acute clinical conditions (such as adult respiratory syndrome and ischemia-reperfusion injury) and in chronic diseases. We investigated the effect of NX21909, a selected oligonucleotide (aptamer) inhibitor of elastase, in an animal model of acute lung inflammatory disease [11-14]. This inhibitor was previously selected from a hybrid library of randomized DNA and a small-molecule irreversible inhibitor of elastase (a valine diphenyl ester phosphonate, Fig. 1), by the blended SELEX process [15]. We show that NX21909 inhibits lung injury and neutrophil influx in a dose-dependent manner, the first demonstration of efficacy by an aptamer in an animal disease model.
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PMID:Protective effects of an aptamer inhibitor of neutrophil elastase in lung inflammatory injury. 938 99

Heat shock proteins (HSPs) have a cytoprotective role in several human diseases, including ischemia and viral infection. Nuclear factor-kappaB (NF-kappaB) is a critical regulator of inflammation and virus replication. Here we report that a class of serine protease inhibitors with NF-kappaB-inhibitory activity are potent HSP inducers via activation of heat shock transcription factor 1 (HSF1) in human cells. 3,4-Dichloroisocoumarin, the most effective compound, rapidly induces HSF1 DNA binding activity and phosphorylation, leading to transcription and translation of heat shock genes for a period of several hours. HSF1 activation is independent of de novo protein synthesis and is correlated in a concentration- and time-dependent manner with NF-kappaB inhibition. Cysteine protease inhibitors E64 and calpain inhibitor II, which do not block NF-kappaB activation, do not induce HSF DNA binding activity. HSP induction by 3,4-dichloroisocoumarin is associated with antiviral activity during rhabdovirus infection. These results identify a new class of HSP inducers and indicate a link between the regulatory pathways of HSF and NF-kappaB, suggesting novel strategies to simultaneously switch on cytoprotective genes and down-regulate inflammatory and viral genes.
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PMID:Activation of the heat shock factor 1 by serine protease inhibitors. An effect associated with nuclear factor-kappaB inhibition. 963 11

Hepatocyte growth factor (HGF) is a potent pleiotrophic peptide which has a trophic role for neuronal cells. As it exerts its effect only after a conversion to its heterodimeric active form, the activation step, which is catalyzed by an enzyme serine protease named HGF activator (HGFA), is of great importance. HGF activated by HGFA may act as a protecting agent in injured brain. In the present study, we investigated expression of immunoreactive HGF and HGFA in rat brain after permanent middle cerebral artery (MCA) occlusion. By immunohistochemical analysis, HGF and HGFA were normally expressed only in ependymal cells and choroid plexus. At 1 h after MCA occlusion, neurons in the ischemic penumbra region of the cerebral cortex slightly expressed immunoreactive HGFA. HGF was not induced at that time. At 3 h of ischemia, however, immunoreactive HGF as well as HGFA became detectable in neurons of the ischemic cerebral cortex and caudate. Immunoreactivity for HGF continued to increase until 24 h, while that for HGFA remained almost constant from 3 to 24 h. No glial or vascular endothelial cells expressed HGF nor HGFA. By Western blot analysis for HGF, a single band of molecular weight (MW) 34 kDa became apparent at 24 h, corresponding to the light chain of the active form HGF. The present study suggests that HGF and HGFA were induced in neurons under permanent ischemia with slightly different temporal profiles. Through activation by HGFA, the active form of HGF could serve as a neurotrophic factor in ischemic brain.
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PMID:Inductions of hepatocyte growth factor and its activator in rat brain with permanent middle cerebral artery occlusion. 967 23

We studied the effects of LEX032, a novel serine protease inhibitor, on N(G)-nitro-L-arginine methyl ester (L-NAME) induced leukocyte-endothelium interactions in vivo, utilizing intravital microscopy of the rat mesentery. Superfusion of the rat mesentery with 50 microM L-NAME, a nitric oxide (NO) inhibitor, for 90 min resulted in a significant and time-dependent increase in leukocyte rolling, leukocyte adherence, and transmigration of leukocytes, compared to control rats superfused with Krebs-Henseleit (K-H) solution. However, systemic administration of LEX032 (15 mg/kg bolus injection followed by a 15 mg/kg per hour infusion) to L-NAME superfused rats significantly attenuated leukocyte rolling and adherence along the venular endothelium of the rat mesentery, and also inhibited transmigration of leukocytes through the microvascular endothelial wall. Moreover, no significant changes were observed in mean arterial blood pressure or local venular shear rates following systemic administration of LEX032. Our data demonstrate that systemic inhibition of serine proteases by LEX032 reduces enhanced leukocyte-endothelium interactions provoked by inhibition of NO synthesis. These results also explain some of the beneficial effects exerted by serine protease inhibitors in ischemia-reperfusion and other inflammatory states.
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PMID:Effects of LEX032, a novel recombinant serine protease inhibitor, on N(G)-nitro-L-arginine methyl ester induced leukocyte-endothelial cell interactions. 976 25

The tissue type plasminogen activator (t-PA) is a serine protease that is involved in neuronal plasticity and cell death induced by excitotoxins and ischemia in the brain. t-PA activity in the central nervous system is regulated through the activation of serine protease inhibitors (serpins) such as the plasminogen activator inhibitor (PAI-1), the protease nexin-1 (PN-1), and neuroserpin (NSP). Recently we demonstrated in vitro that PAI-1 produced by astrocytes mediates the neuroprotective effect of the transforming growth factor-beta1 (TGF-beta1) in NMDA-induced neuronal cell death. To investigate whether serpins may be involved in neuronal cell death after cerebral ischemia, we determined, by using semiquantitative RT-PCR and in situ hybridization, that focal cerebral ischemia in mice induced a dramatic overexpression of PAI-1 without any effect on PN-1, NSP, or t-PA. Then we showed that although the expression of PAI-1 is restricted to astrocytes, PN-1, NSP, and t-PA are expressed in both neurons and astrocytes. Moreover, by using semiquantitative RT-PCR and Western blotting, we observed that only the expression of PAI-1 was modulated by TGF-beta1 treatment via a TGF-beta-inducible element contained in the PAI-1 promoter (CAGA box). Finally, we compared the specificity of TGF-beta1 action with other members of the TGF-beta family by using luciferase reporter genes. These data show that TGF-beta and activin were able to induce the overexpression of PAI-1 in astrocytes, but that bone morphogenetic proteins, glial cell line-derived neutrophic factor, and neurturin did not. These results provide new insights into the regulation of the serpins/t-PA axis and the mechanism by which TGF-beta may be neuroprotective.
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PMID:Transforming growth factor-beta1 as a regulator of the serpins/t-PA axis in cerebral ischemia. 1042 56

Although the serine protease, tissue plasminogen activator (tPA), is approved by the US Food and Drug Administration for therapy to combat focal cerebral infarction, the basic concept of thrombolytic tPA therapy for stroke was challenged by recent studies that used genetically manipulated tPA-deficient (tPA-/-) mice, which suggested that tPA mediates ischemic neuronal damage. However, those studies were potentially flawed because the genotypes of tPA-/- and wild-type control mice were not entirely clear, and ischemic neuronal injury was evaluated in isolation of tPA effects on brain thrombosis. Using mice with appropriate genetic backgrounds and a middle cerebral artery occlusion stroke model with nonsiliconized thread, which does lead to microvascular thrombus formation, in the present study we determined the risk for cerebrovascular thrombosis and neuronal injury in tPA-/- and genetically matched tPA+/+ mice subjected to transient focal ischemia. Cerebrovascular fibrin deposition and the infarction volume were increased by 8.2- and 6. 7-fold in tPA-/- versus tPA+/+ mice, respectively, and these variables were correlated with reduced cerebral blood flow up to 58% (P<0.05) and impaired motor neurological score by 70% (P<0.05). Our findings indicate that tPA deficiency exacerbates ischemia-induced cerebrovascular thrombosis and that endogenous tPA protects the brain from an ischemic insult, presumably through its thrombolytic action. In addition, our study emphasizes the importance of appropriate genetic controls in murine stroke research.
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PMID:Tissue plasminogen activator (tPA) deficiency exacerbates cerebrovascular fibrin deposition and brain injury in a murine stroke model: studies in tPA-deficient mice and wild-type mice on a matched genetic background. 1089 28

Activated factor X (FXa) is a trypsinlike serine protease involved in the cascade of blood coagulation. The monocyte chemoattractant protein-1 (MCP-1) may be important in the pathophysiology of liver ischemia-reperfusion injury. We investigated the effects of a selective FXa inhibitor, DX-9065a, on MCP-1 expression after ischemia-reperfusion in the rat liver. Liver ischemia was induced in rats by occluding the portal vein for 30 min. DX-9065a was injected intravenously 5 min before vascular clamping. Serum concentrations of MCP-1 were measured by enzyme-linked immunosorbent assay. The levels of MCP-1 mRNA in the liver after reperfusion were determined by northern blot analysis. In vitro MCP-1 production by peritoneal macrophages in response to alpha-thrombin was examined. Serum concentrations of MCP-1 increased and peaked at 6 hr after reperfusion. However, pretreatment of animals with DX-9065a resulted in significantly smaller increases in the serum concentration of MCP-1 after reperfusion in a dose-dependent manner. Pretreatment with DX-9065a significantly reduced MCP-1 mRNA levels in the liver after ischemia-reperfusion. In vitro MCP-1 production by peritoneal macrophages was enhanced by alpha-thrombin. In addition, DX-9065a significantly reduced tissue factor mRNA levels in peripheral monocytes after ischemia-reperfusion, compared to untreated animals. In conclusion, a selective inhibitor of FXa, DX-9065a, limited MCP-1 production after ischemia-reperfusion of the rat liver.
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PMID:A synthetic selective inhibitor of factor Xa, DX-9065a, reduces monocyte chemoattractant protein-1 expression after ischemia-reperfusion injury in rat liver. 1063 May 15


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