Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein C, a vitamin K-dependent serine protease zymogen that circulates in plasma, is converted by limited proteolysis to activated protein C (APC) by the thrombin-thrombomodulin complex. APC exerts anticoagulant, antiinflammatory, cytoprotective, and antiapoptotic activities. Recombinant APC therapy reduces mortality in severe sepsis patients. This review summarizes data from clinical observations, from in vitro studies, and from animal models of focal ischemic injury that provide a compelling rationale for clinical trials of APC for ischemic stroke.
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PMID:The promise of protein C. 1646 23

Inter-alpha inhibitor proteins (IaIp) are a family of structurally related serine protease inhibitors found in relatively high concentrations in human plasma. Recent studies have implicated a role for IaIp in sepsis, and have demonstrated their potential as biomarkers in sepsis and cancer. For characterization of isolated IaI proteins and contaminating proteins during the last steps of the purification process, SELDI-TOF MS and HPLC-ESI-MS/MS were used. After separation by SDS-PAGE or 2-DE, polypeptide bands of 80, 125 and 250 kDa were excised from gels and digested by trypsin. The tryptic peptides were analyzed by both MS methods. The main contamination during the purification process, a band of 80 kDa, contains mainly IaIp heavy chain (HC) H3. HC H1 and H2 were also found in this band. In addition, some vitamin K-dependent clotting factors and inhibitors and other plasma proteins were identified. The 125-kDa band, representing the pre-alpha inhibitor, was found to contain both bikunin and HC H3. The presence of other HC H1, H2 and the recently described HC H4 was also detected by SELDI-TOF MS. The presence of HC H1, H2, and H3 in the 125-kDa band was confirmed by ESI-MS/MS, but not the presence of the H4. Three polypeptides, H1 and H2 together with bikunin, were identified in the 250-kDa band, representing the ITI, by both MS techniques. Once again, the presence of H4 was detected in this band only by SELDI-TOF MS, but the number of corresponding peptides was still not sufficient for final identification of this polypeptide. The importance of the application of proteomic methods for the proper evaluation of therapeutic drugs based on human plasma is discussed.
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PMID:Proteomic characterization of inter-alpha inhibitor proteins from human plasma. 1659 6

The anticoagulant protein C system is a dual function cofactor-dependent system. On one hand, it is designed to regulate coagulation, maintain the fluidity of the vasculature and prevent thrombosis. On the other hand, the protein C pathway provides anti-inflammatory and cytoprotective activities. Protein C, a vitamin K-dependent serine protease zymogen that circulates in plasma, is converted by limited proteolysis to activated protein C (APC) by the thrombin-thrombomodulin-endothelial protein C receptor complex on endothelial surfaces. APC and the cofactors of the protein C pathway exert two major distinct types of activities, namely a well-studied anticoagulant activity and a more recently revealed cytoprotective activity due to direct effects on cells. Because of these pleiotropic properties, APC and the protein C pathway components have important roles in the body's host-defense system and provide opportunities for therapeutic treatment of complex and challenging medical disorders, including thrombosis, severe sepsis and stroke.
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PMID:Protein C anticoagulant activity in relation to anti-inflammatory and anti-apoptotic activities. 1672 Mar 21

Sepsis is one of the common causes of acute renal failure (ARF). The objective of this study was to identify new biomarkers and therapeutic targets. We present a new rat model of sepsis-induced ARF based on cecal ligation and puncture (CLP). We used this model to find urinary proteins which may be potential biomarkers and/or drug targets. Aged rats were treated with fluids and antibiotics after CLP. Urinary proteins from septic rats without ARF and urinary proteins from septic rats with ARF were compared by difference in-gel electrophoresis (DIGE). CLP surgery elevated interleukin (IL)-6 and IL-10 serum cytokines and blood nitrite compared with sham-operated rats. However, there was a range of serum creatinine values at 24 h (0.4-2.3 mg/dl) and only 24% developed ARF. Histology confirmed renal injury in these rats. Forty-nine percent of rats did not develop ARF. Rats without ARF also had less liver injury. The mortality rate at 24 h was 27% but was increased by housing the post-surgery rats in metabolic cages. Creatinine clearance and urine output 2-8 h after CLP was significantly reduced in rats which died within 24 h. Using DIGE we identified changes in a number of urinary proteins including albumin, brush-border enzymes (e.g., meprin-1-alpha) and serine protease inhibitors. The meprin-1-alpha inhibitor actinonin prevented ARF in aged mice. In summary, we describe a new rat model of sepsis-induced ARF which has a heterogeneous response similar to humans. This model allowed us to use DIGE to find changes in urinary proteins and this approach identified a potential biomarker and drug target - meprin-1-alpha.
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PMID:Biomarker and drug-target discovery using proteomics in a new rat model of sepsis-induced acute renal failure. 1676 Sep 4

Activated protein C is the first effective biological therapy for the treatment of severe sepsis. Although activated protein C is well established as a physiological anticoagulant, emerging data suggest that it also exerts anti-inflammatory and antiapoptotic effects. In this study, we investigated the ability of activated protein C to modulate monocyte apoptosis, inflammation, phagocytosis, and adhesion. Using the immortalized human monocytic cell line THP-1, we demonstrated that activated protein C inhibited camptothecin-induced apoptosis in a dose-dependent manner. The antiapoptotic effect of activated protein C requires its serine protease domain and is dependent on the endothelial cell protein C receptor and protease-activated receptor-1. In primary blood monocytes from healthy individuals, activated protein C inhibited spontaneous apoptosis. With respect to inflammation, activated protein C inhibited the production of TNF, IL-1beta, IL-6, and IL-8 by LPS-stimulated THP-1 cells. Activated protein C did not influence the phagocytic internalization of Gram-negative and Gram-positive bioparticles by THP-1 cells or by primary blood monocytes. Activated protein C also did not affect the expression of adhesion molecules by LPS-stimulated blood monocytes nor the ability of monocytes to adhere to LPS-stimulated endothelial cells. We hypothesize that the protective effect of activated protein C in sepsis reflects, in part, its ability to prolong monocyte survival in a manner that selectively inhibits inflammatory cytokine production while maintaining phagocytosis and adherence capabilities, thereby promoting antimicrobial properties while limiting tissue damage.
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PMID:Modulation of monocyte function by activated protein C, a natural anticoagulant. 1688 70

Therapeutic complement inhibition is a promising strategy for treatment of a number of diseases as judged from rodent studies. The species distance from rodents to humans may limit the clinical relevance of these studies. The pig is an alternative animal for studies of human diseases like sepsis and ischemia/reperfusion injury. However, available complement inhibitors for use in pigs are scarce. The aim of the present study was to investigate and compare the efficacy of selected candidate inhibitors of porcine complement in vitro for possible future application in vivo. Sera from three different pigs were each incubated with three different activators of the complement system (zymosan, heat-aggregated immunoglobulin G (HAIGG) and Escherichia coli). Three groups of complement inhibitor candidates were tested: serine protease inhibitors (FUT-175 and C1-inhibitor), monoclonal antibodies (anti-factor B (fB) and anti-factor D (fD)) and a recombinant regulatory protein (vaccinia virus complement control protein (VCP)). Read-out was the terminal C5b-9 complement complex (TCC). The serine protease inhibitors FUT-175 and C1-inhibitor dose-dependently inhibited TCC formation in zymosan-, HAIGG- and E. coli-activated porcine sera, but with different efficacy. Complete inhibition of TCC was obtained using 0.2 mg/mL FUT-175, but required 16 mg/mL of C1-inhibitor. The monoclonal anti-fB and -fD antibodies both inhibited TCC formation dose-dependently, but in different ways. Anti-fB at high dose (1 mg/mL) completely inhibited TCC formation in sera activated with zymosan and virtually completely in sera activated with HAIGG, but not in sera activated with E. coli. Anti-fD inhibited all three activators at low dose (0.05 mg/mL), and approximately 50% TCC reduction was obtained. The recombinant complement regulatory protein VCP efficiently and dose-dependently inhibited TCC formation with a complete inhibition found at 0.05 mg/mL for all three activators. All candidates tested inhibited porcine complement activation, but in different ways and to different degrees. Of the complement-specific candidates, VCP inhibited all activators completely at low doses.
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PMID:Candidate inhibitors of porcine complement. 1710 63

Activated protein C (APC), a plasma serine protease, is best known for its ability to inhibit blood clot formation. APC acts as an anticoagulant by degrading coagulation cofactors Va and VIIIa, thereby attenuating the coagulation cascade. Over the past 15 years, impressive research advances have provided novel insights into the diverse biological activities of this molecule. APC is now viewed not only as an anticoagulant but also as a signaling molecule that provides a pivotal link between the pathways of coagulation, inflammation, apoptosis, and vascular permeability. The protective effect of APC supplementation in patients with severe sepsis likely reflects the ability of APC to modulate multiple pathways implicated in sepsis pathophysiology. This review attempts to summarize key studies that support the therapeutic potential of APC in conditions beyond sepsis such as stroke, ischemia-reperfusion injury, lung injury, asthma, pancreatitis, wound healing, and angiogenesis. A comprehensive PUBMED literature review up to May 2006 was conducted.
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PMID:Activated protein C in sepsis and beyond: update 2006. 1712 35

Aeromonas hydrophila is a ubiquitous Gram-negative bacterium which can cause motile aeromonad septicemia in both fish and humans. A. hydrophila secretes many extracellular proteins associated with pathogenicity and environmental adaptability. In this study, an extracellular proteome map of A. hydrophila AH-1 was constructed. The major extracellular virulence factors were characterized by comparing the proteomes of various deletion mutants with that of the wild type. The results suggested that serine protease was involved in the processing of a toxin and secreted enzymes such as hemolysin, glycerophospholipid-cholesterol acyltransferase and metalloprotease. We also showed that expressions of polar and lateral flagellins were under the control of temperature, FlhA, LafK, and RpoN. In addition, three novel proteins (potential effector proteins including one ExoT-like protein) were revealed to be secreted via the type III secretion system (TTSS) of A. hydrophila AH-1. Another novel finding was the demonstration of a crosstalk between the lateral flagellar system and the TTSS in A. hydrophila. These results showed that proteomics is a powerful tool for characterizing virulence factors. The construction of proteome maps will provide a valuable means of finding potential candidates for developing suitable diagnostics and therapeutics for this emerging pathogen.
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PMID:Characterization of extracellular proteins produced by Aeromonas hydrophila AH-1. 1720 9

Activated protein C (APC) is a vitamin K-dependent plasma serine protease which down-regulates the clotting cascade by inactivating procoagulant factors Va and VIIIa by limited proteolysis. In addition to its anticoagulant effect, APC also exhibits cytoprotective and antiinflammatory activity through the endothelial protein C receptor-dependent cleavage of protease activated receptor 1 (PAR-1) on endothelial cells. Recent mutagenesis data have indicated that the basic residues of two surface loops including those on 39 and the Ca2+-binding 70-80 loops constitute interactive sites for both factors Va and VIIIa, thereby mediating the interaction of APC specifically with these procoagulant cofactors. The basic residues of both loops have been discovered to be dispensable for the interaction of APC with PAR-1. It is not known if a similar exosite-dependent interaction contributes to the specificity of APC recognition of PAR-1 on endothelial cells. In this study, we have identified two acidic residues on helix-162 (Glu-167 and Glu-170) on the protease domain of APC which are required for the protease interaction with PAR-1, but not for its interaction with the procoagulant cofactors. Thus, the substitution of either Glu-167 or Glu-170 with Ala eliminated the cytoprotective signaling properties of APC without affecting its anticoagulant activity. These mutants provide useful tools for initiating in vivo studies to understand the extent to which the anticoagulant versus antiinflammatory activity of APC contributes to its beneficial effect in treating severe sepsis.
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PMID:Identification of a specific exosite on activated protein C for interaction with protease-activated receptor 1. 1758 Mar 6

Group B streptococci (GBS) are the most common cause of neonatal sepsis and meningitis. Most infants who are colonized with GBS at birth do not develop invasive disease, although many of these uninfected infants lack protective levels of capsular polysaccharide (CPS)-specific antibody. The lectin pathway of complement is a potential mechanism for initiating opsonization of GBS with CPS-specific antibody-deficient serum. In this study, we determined whether mannose-binding lectin (MBL)/MBL-associated serine protease (MASP) complexes and L-ficolin/MASP complexes bind to different strains of GBS to activate the lectin pathway, and we identified the molecules recognized by lectins on the GBS surface. We found that MBL did not bind to any GBS examined, whereas L-ficolin bound to GBS cells of many serotypes. L-ficolin binding to GBS cells correlated with the CPS content in serotypes Ib, III (restriction digestion pattern types III-2 and III-3), and V but not with the group B-specific polysaccharide (GBPS) content or with the lipoteichoic acid (LTA) content. L-ficolin bound to purified CPS and GBPS in a concentration-dependent manner but not to purified LTA. All strains to which L-ficolin/MASP complexes bound consumed C4. When N-acetylneuraminic acid (NeuNAc) was selectively removed from GBS cells by treatment with neuraminidase, the reduction in L-ficolin binding was correlated with the amount of NeuNAc removed. Additionally, L-ficolin was able to bind to wild-type strains but was able to bind only weakly to unencapsulated mutants and a mutant strain in which the CPS lacks NeuNAc. We concluded that L-ficolin/MASP complexes bind to GBS primarily through an interaction with NeuNAc of CPS.
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PMID:L-Ficolin/mannose-binding lectin-associated serine protease complexes bind to group B streptococci primarily through N-acetylneuraminic acid of capsular polysaccharide and activate the complement pathway. 1793 15


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