Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure of blood to tissue factor (TF) rapidly initiates the coagulation serine protease cascades. TF is expressed by macrophages and other types of cell within atherosclerotic lesions and plays an important role in thrombus formation after plaque rupture. Macrophage TF expression is induced by pro-inflammatory stimuli including lipopolysaccharide (LPS), interleukin-1beta and tumor necrosis factor-alpha. Here we demonstrate that activation of liver X receptors (LXRs) LXRalpha and LXRbeta suppresses TF expression. Treatment of mouse peritoneal macrophages with synthetic LXR agonist T0901317 or GW3965 reduced TF expression induced by pro-inflammatory stimuli. LXR agonists also suppressed TF expression and its activity in human monocytes. Human and mouse TF promoters contain binding sites for the transcription factors AP-1, NFkappaB, Egr-1 and Sp1, but no LXR-binding sites could be found. Cotransfection assays with LXR and TF promoter constructs in RAW 264.7 cells revealed that LXR agonists suppressed LPS-induced TF promoter activity. Analysis of TF promoter also showed that inhibition of TF promoter activity by LXR was at least in part through inhibition of the NFkappaB signaling pathway. In addition, in vivo, LXR agonists reduced TF expression within aortic lesions in an atherosclerosis mouse model as well as in kidney and lung in mice stimulated with LPS. These findings indicate that activation of LXR results in reduction of TF expression, which may influence atherothrombosis in patients with vascular disease.
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PMID:Liver X receptor agonists inhibit tissue factor expression in macrophages. 1575 69

Serine protease inhibitors, termed serpins, are key regulators of numerous biological pathways that initiate inflammation, coagulation, angiogenesis, apoptosis, extra-cellular matrix composition and complement activation responses. Viruses have encoded serpins to guard themselves from host immune attack. The myxoma virus which infects rabbits secretes a highly potent anti-inflammatory serpin, Serp-1, which targets thrombolytic and thrombotic proteases as a means to fend off coagulation and inflammatory reactions to viral infection. These reactions act as a defense, produced by the host, to counter viral infection and invasion. When infused in animals after vascular injury, Serp-1 elicits exceptional anti-inflammatory activity, whereas the mammalian serpin, plasminogen activator inhibitor-1 (PAI-1), which also targets thrombotic and thrombolytic proteases can induce a pro-thrombotic response. During arterial injury, PAI-1 is highly expressed and increased PAI-1 concentration can result in acute thrombosis after aortic transplant in mouse models. The reactive center loop amino acid sequence is a fingerprint for serpin function and this function is highly sequence specific such that modification in this sequence can markedly alter activity. For instance, the alteration of the serpin reactive site loop P1-P1I amino acid sequence nullified the anti-inflammatory activity of Serp-1 and modification of P2-P7 initiated a pro-inflammatory response with vascular remodeling with aneurysm formation. Furthermore Serp-1 has demonstrated the capacity to utilize a mammalian serine protease receptor, the urokinase-type plasminogen activator receptor (uPAR), to alter cellular signaling in part through the actin binding protein cytoskeletal system (via filamin B). In this review, the molecular mechanisms relating inflammation and coagulation pathways to atherosclerosis and how the viral serpin, Serp-1, modifies these pathways in order to exhibit this profound anti-inflammatory activity without associated adverse thrombosis are discussed. Viral and vascular serpins targeting the thrombolytic cascade represent a potential new and untapped therapeutic resource.
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PMID:Serpins, the vasculature, and viral therapeutics. 1614 96

Elevated levels of circulating low-density lipoprotein cholesterol (LDL-C) play a central role in the development of atherosclerosis. Mutations in proprotein convertase subtilisin/kexin type 9 (PCSK9) that are associated with lower plasma levels of LDL-C confer protection from coronary heart disease. Here, we show that four severe loss-of-function mutations prevent the secretion of PCSK9 by disrupting synthesis or trafficking of the protein. In contrast to recombinant wild-type PCSK9, which was secreted from cells into the medium within 2 hours, the severe loss-of-function mutations in PCSK9 largely abolished PCSK9 secretion. This finding predicted that circulating levels of PCSK9 would be lower in individuals with the loss-of-function mutations. Immunoprecipitation and immunoblotting of plasma for PCSK9 provided direct evidence that the serine protease is present in the circulation and identified the first known individual who has no immunodetectable circulating PCSK9. This healthy, fertile college graduate, who was a compound heterozygote for two inactivating mutations in PCSK9, had a strikingly low plasma level of LDL-C (14 mg/dL). The very low plasma level of LDL-C and apparent good health of this individual demonstrate that PCSK9 plays a major role in determining plasma levels of LDL-C and provides an attractive target for LDL-lowering therapy.
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PMID:Molecular characterization of loss-of-function mutations in PCSK9 and identification of a compound heterozygote. 1690 89

Adverse cardiovascular events are the consequence of a molecular chain reaction at the site of vulnerable plaques. Key players are platelets and coagulation factors that are activated following plaque rupture and often cause arterial obstruction. Thrombin, a plasma serine protease, plays a role in hemostasis of coagulation as well as in thrombosis and cell growth, leading to restenosis and atherosclerosis. Interesting and promising new molecules, the direct thrombin inhibitors, have been shown to be as effective as the combination of glycoprotein IIb-IIIa inhibitors and heparin for the prevention of arterial thrombosis. Until recently, direct thrombin inhibitors could be applied only parenterally; therefore, therapy was limited to hospitalized patients. As a result of recent drug development, orally active direct thrombin inhibitors are now available and have been evaluated for the long-term treatment of venous thrombosis and arterial fibrillation. Due to their specific pharmacodynamic characteristics by binding directly to thrombin--and thus inhibiting platelet aggregation and fibrin generation--these novel drugs may also have therapeutic potential for the treatment of atherothrombotic disease and its complications such as myocardial infarction, stroke or limb ischemia.
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PMID:Therapeutical potential of direct thrombin inhibitors for atherosclerotic vascular disease. 1746 31

Clearance of fibrin through proteolytic degradation is a critical step of matrix remodeling that contributes to tissue repair in a variety of pathological conditions, such as stroke, atherosclerosis, and pulmonary disease. However, the molecular mechanisms that regulate fibrin deposition are not known. Here, we report that the p75 neurotrophin receptor (p75(NTR)), a TNF receptor superfamily member up-regulated after tissue injury, blocks fibrinolysis by down-regulating the serine protease, tissue plasminogen activator (tPA), and up-regulating plasminogen activator inhibitor-1 (PAI-1). We have discovered a new mechanism in which phosphodiesterase PDE4A4/5 interacts with p75(NTR) to enhance cAMP degradation. The p75(NTR)-dependent down-regulation of cAMP results in a decrease in extracellular proteolytic activity. This mechanism is supported in vivo in p75(NTR)-deficient mice, which show increased proteolysis after sciatic nerve injury and lung fibrosis. Our results reveal a novel pathogenic mechanism by which p75(NTR) regulates degradation of cAMP and perpetuates scar formation after injury.
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PMID:p75 neurotrophin receptor regulates tissue fibrosis through inhibition of plasminogen activation via a PDE4/cAMP/PKA pathway. 1757 3

Atherosclerosis is initially a chronic inflammatory disease as it involves inflammatory cells such as macrophages, T-lymphocytes and mast cells. At later stages, when plaques manifest clinically, thrombosis, coagulation and fibrinolysis contribute to the escalation of the disease, which culminates in acute cardiovascular syndromes. Serine proteases are instrumental in all of these processes, rendering their inhibition of clinical interest for the prevention of atherosclerotic plaque progression. Viral serine protease inhibitors, specifically engineered by pathogens to evade the host's defense system, not only display profound anti-inflammatory activity but also inhibit a range of serine proteases implicated in cardiovascular disease. In this review, the potential of viral serine protease inhibitors in anti-atherosclerotic therapy is discussed.
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PMID:Viral serine protease inhibitors as anti-atherosclerotic therapy. 1772 84

Thrombin is a multifunctional serine protease generated at the site of vascular injury that transforms fibrinogen into fibrin, activates blood platelets and elicits multiple effects on a variety of cell types including endothelial cells, vascular smooth muscle cells (VSMC), monocytes, T lymphocytes and fibroblasts. Cellular effects of thrombin are mediated by protease-activated receptors (PARs), members of the G protein-coupled receptors that carry their own ligand which remains cryptic until unmasked by proteolytic cleavage. Thrombin signalling in platelets contributes to haemostasis and thrombosis. In normal arteries PARs are mainly expressed in endothelial cells, while their expression in VSMC is limited. Endothelial PARs participate in the regulation of vascular tone, vascular permeability and endothelial secretory activity while in VSMC they mediate contraction, migration, proliferation, hypertrophy and production of extracellular matrix. PARs contribute to the pro-inflammatory phenotype observed in endothelial dysfunction and their up-regulation in VSMC seems to be a key element in the pathogenesis of atherosclerosis and restenosis. In the last years a myriad of studies have emphasized the critical role of PAR signalling in thrombin mediated effects in haemostasis, inflammation, cancer and embryonic development. Lately, PARs have become a therapeutic target to inhibit platelet aggregation and thrombosis. Early data from a clinical trial (TRA-PCI) to evaluate safety and efficacy of a potent new oral thrombin receptor antagonist (TRA) have promisingly indicated that overall TRA treatment reduces adverse event rates without an increase in bleeding risk. In this paper we review cellular responses triggered by thrombin and their implication in vascular pathophysiology.
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PMID:Thrombin and protease-activated receptors (PARs) in atherothrombosis. 1827 79

The plasma level of LDL cholesterol is clinically important and genetically complex. LDL cholesterol levels are in large part determined by the activity of LDL receptors (LDLR) in the liver. Autosomal dominant familial hypercholesterolaemia (FH) - with its high LDL cholesterol levels, xanthomas, and premature atherosclerosis - is caused by mutations in either the LDLR or in APOB - the protein in LDL recognised by the LDLR. A third, rare form - autosomal recessive hypercholesterolaemia - arises from mutations in the gene encoding an adaptor protein involved in the internalisation of the LDLR. A fourth variant of inherited hypercholesterolaemia was recently found to be associated with missense mutations in PCSK9, which encodes a serine protease that degrades LDLR. Whereas the gain-of-function mutations in PCSK9 are rare, a spectrum of more frequent loss-of-function mutations in PCSK9 associated with low LDL cholesterol levels has been identified in selected populations and could protect against coronary heart disease. Heterozygous familial hypobetalipoproteinaemia (FHBL) - with its low LDL cholesterol levels and resistance to atherosclerosis - is caused by mutations in APOB. In contrast to other inherited forms of severe hypocholesterolaemia such as abetalipoproteinaemia - caused by mutations in MTP - and homozygous FHBL, a deficiency of PCSK9 appears to be benign. Rare variants of NPC1L1, the gene encoding the putative intestinal cholesterol receptor, have shown more modest effects on plasma LDL cholesterol than PCSK9 variants, similar in magnitude to the effect of common APOE variants. Taken together, these findings indicate that heritable variation in plasma LDL cholesterol is conferred by sequence variation in various loci, with a small number of common and multiple rare gene variants contributing to the phenotype.
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PMID:Common and rare gene variants affecting plasma LDL cholesterol. 1856 65

Diabetic micro- and macroangiopathies are leading causes of acquired blindness, end-stage renal failure and accelerated atherosclerosis, which could account for disabilities and high mortality rates in patients with diabetes. Recent large landmark clinical studies have shown that intensive control of blood glucose or blood pressure (BP) reduces the risk for vascular complications in diabetes. However, the strict control of blood glucose or BP is often difficult to maintain, and current therapeutic options are far from satisfactory. Therefore, to develop novel therapeutic strategies that specifically target vascular complications in diabetes may be actually desired for most patients with diabetes. Pigment epithelium-derived factor (PEDF) is a glycoprotein that belongs to the superfamily of serine protease inhibitors with complex neurotrophic, neuroprotective, anti-angiogenic, anti-oxidative, and anti-inflammatory properties, any of which could potentially be exploited as a therapeutic option for the treatment of vascular complications in diabetes. This article summarizes the pathophysiological role of PEDF for vascular complication in diabetes and its potential therapeutic implication in this devastating disorder.
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PMID:Pigment epithelium-derived factor (PEDF): its potential therapeutic implication in diabetic vascular complications. 1899 13

Factor VII-activating protease (FSAP) circulates as an inactive zymogen in the plasma. FSAP also regulates fibrinolysis by activating pro-urokinase or cellular activation via cleavage of platelet-derived growth factor BB (PDGF-BB). As the Marburg I polymorphism of FSAP, with reduced enzymatic activity, is a risk factor for atherosclerosis and liver fibrosis, the regulation of FSAP activity is of major importance. FSAP is activated by an auto-catalytic mechanism, which is amplified by heparin. To further investigate the structural requirements of polyanions for controlling FSAP activity, we performed binding, activation and inhibition studies using heparin and derivatives with altered size and charge, as well as other glycosaminoglycans. Heparin was effective in binding to and activating FSAP in a size- and charge density-dependent manner. Polyphosphate was more potent than heparin with regard to its interactions with FSAP. Heparin was also an effective co-factor for inhibition of FSAP by plasminogen activator inhibitor 1 (PAI-1) and antithrombin, whereas polyphosphate served as co-factor for the inhibition of FSAP by PAI-1 only. For FSAP-mediated inhibition of PDGF-BB-induced vascular smooth muscle cell proliferation, heparin as well as a polyphosphate served as efficient co-factors. Native mast cell-derived heparin exhibited identical properties to those of unfractionated heparin. Despite the strong effects of synthetic polyphosphate, the platelet-derived material was a weak activator of FSAP. Hence, negatively charged polymers with a high charge-to-size ratio are responsible for the activation of FSAP, and also act as co-factors for its inhibition by serine protease inhibitors.
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PMID:High negative charge-to-size ratio in polyphosphates and heparin regulates factor VII-activating protease. 1966 58


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