Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0012739 (disseminated intravascular coagulation)
 8,673 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endotoxin(lipopolysaccharide = LPS), cell wall component of gram-negative bacteria, activates monocytes and macrophages to release cytokines, reactive nitrogen intermediates (RNI), and to generate tissue factor(TF) which initiate coagulation. We have purified 7kDa and 18kDa cationic antibacterial proteins (CAP-7 and CAP-18) with LPS-binding and LPS-neutralizing activities from rabbit granulocytes using as an assay the agglutination of erythrocytes coated with Re-LPS. From protein sequencing, CAP-7 was identified as the C-terminal 37 amino acid fragment of CAP-18. Synthetic peptide #197 (identical sequence to CAP-7, Gly1-Try37) and #36-1 (a truncation of CAP consisting of 32 amino acid residues, Gly1-Ala32) showed LPS-binding activity. Each peptide inhibited LPS-induced tissue factor(TF) generation by murine peritoneal macrophages, even added 1-3 hours after stimulation of cells with LPS. C57BL/6 mice treated with #197 were significantly protected from lethal LPS challenge. Peptide #36 also blocked the LPS-induced lethality. These peptides had antibacterial activity to gram-negative bacteria, such as E.coli, S.typhimurium, K.pneumonia, Ps.aeruginosa and also to gram-positive S.aureus (Methicillin sensitive and resistant strains). Both peptides inhibited TF- and Xa-induced plasma clotting. Using synthetic chromotogenic substrates, both CAP7 peptides blocked the coagulation cascade at two sites, activation of factor X to Xa and conversion of Factor II (prothrombin) to factor IIa (thrombin). In vivo treatment of peptide #197 prevented acute lethality in mice injected with tissue factor (rabbit brain thromboplastin). Two other peptides, #32(Gly1-Phe9) and #50(Ile13-Typ37) failed to demonstrate LPS-binding, LPS-neutralizing, antibacterial and anticoagulant activities. The active peptides but not the inactive peptide maintain a putative heparin binding domain at their N-termini. This heparin binding domain is participate in the LPS-binding, LPS neutralizing, antibacterial and anticoagulant activities of CAP7. These active peptides may have a therapeutic potential for treatment for DIC due to sepsis and endotoxin shock.
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PMID:Endotoxin-binding synthetic peptides with endotoxin-neutralizing, antibacterial and anticoagulant activities. 783 55

CAP18 (cationic antimicrobial protein, 18kDa) is a 142 amino acid protein originally isolated from rabbit granulocytes using agglutination of LPS-coated erythrocytes as an assay. CAP-18 is composed of an N-terminal domain of unknown function (CAP181-105) and a C-terminal LPS-binding domain (CAP18106-142). Synthetic CAP18106-142 and CAP18106-137, a 32-amino acid peptide resulting from the truncation of 5 amino acids from the C-terminus of CAP18106-142, inhibited LPS-induced tissue factor generation, nitric oxide production and TNF release by macrophages. Mice treated with CAP18106-142 or CAP18106-137 were significantly protected from LPS lethality. Although CAP18106-142 and CAP18106-137 were highly active, other fragments of CAP18106-142, including CAP18110-142 with a truncated N-terminus, did not exhibit LPS-binding and LPS-neutralizing activities. Both peptides had broad anti-microbial activity against both Gram-negative bacteria such as Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa (IC50; 40-100 nM) and Gram-positive bacteria such as Staphylococcus aureus(Methicillin sensitive and resistant strains) and Streptococcus pneumoniae (IC50; 100-200nM). We cloned a CAP18 family protein from human granulocytes. The cloned cDNA encoded 140 amino acid residues. Human CAP18 (CAP181-140) was highly homologous to that of rabbit. A 32- amino-acid C-terminal fragment (CAP18104-135) was shown to bind LPS, inhibit LPS-induced tissue factor generation by murine macrophages, and protect mice from LPS lethality. This peptide exhibited antimicrobial activity against both Gram-negative and Gram-positive bacteria. We hypothesize that CAP18 and the derived peptides bind to LPS and alter the capacity of LPS to initiate disseminated intravascular coagulation. In this regard, CAP may act as host defense protein against infectious diseases, and have therapeutic potential for sepsis and endotoxin shock.
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PMID:Structure and functions of endotoxin-binding peptides derived from CAP18. 852 37