Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endotoxin (lipopolysaccharide [LPS]) is the major pathogenic factor of gram-negative septic shock, and endotoxin-induced death is associated with the host overproduction of tumor necrosis factor alpha (TNF-alpha). In the search for new antiendotoxin molecules, we studied the endotoxin-neutralizing capacity of a human lactoferrin-derived 33-mer synthetic peptide (GRRRRSVQWCAVSQPEATKCFQWQRNMRKVRGP; designated LF-33) representing the minimal sequence for lactoferrin binding to glycosaminoglycans. LF-33 inhibited the coagulation of the Limulus amebocyte lysate and the secretion of TNF-alpha by RAW 264.7 cells induced by lipid A and four different endotoxins with a potency comparable to that of polymyxin B. The first six residues at the N terminus of LF-33 were critical for its antiendotoxin activity. The endotoxin-neutralizing capacity of LF-33 and polymyxin B was attenuated by human serum. Coinjection of Escherichia coli LPS (125 ng) with LF-33 (2.5 microg) dramatically reduced the lethality of LPS in the galactosamine-sensitized mouse model. Significant protection of the mice against the lethal LPS challenge was also observed when LF-33 (100 microg) was given intravenously after intraperitoneal injection of LPS. Protection was correlated with a reduction in TNF-alpha levels in the mouse serum. These results demonstrate the endotoxin-neutralizing capability of LF-33 in vitro and in vivo and its potential use for the treatment of endotoxin-induced septic shock.
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PMID:Neutralization of endotoxin in vitro and in vivo by a human lactoferrin-derived peptide. 1002 82

Oligonucleotide N3'->P5' Phosphoramidates (PN) may confer advantages over unmodified phosphodiester compounds for therapeutic applications (1). Previous in vitro data demonstrated that PN Oligodeoxynucleotides (ODNs) possess several advantageous features, including RNase H-independence, an improved resistance to nuclease degradation, decreased protein binding, and high affinity sequence-specific binding to complementary RNAs (1, 2). Consequently, we undertook a study to investigate the effects of PN antisense (AS) oligos targeted against the p65 subunit of the Nuclear Factor Kappa beta (NF-kappaB) transcription factor in vivo, in mice. The ability of the antisense molecules to inhibit IL-6 elevation induced by lipopolysaccharide (LPS) in mice, was studied. A 16 mer uniformly modified PN and a chimeric phosphoramidate-phosphodiester oligodeoxynucleotide complementary to the region surrounding the starting codon, (PN-PO-PN) of the NK-kappaB p65 subunit mRNA, both caused a sequence specific reduction of the serum IL-6 level in mice. A scrambled oligodeoxynucleotide showed much lower IL-6 inhibition in mice. These results show that the p65 PN-AS can modulate expression of IL-6 in mice without uptake enhancers and therefore may be a useful prototype for RNAse-H independent therapeutic agents.
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PMID:Inhibition of IL-6 in mice by anti-NF-kappaB oligodeoxyribonucleotide N3'-->oligodeoxyribonnucleotide N3' --> P5' phosphoramidates. 1056 71

DNA is a complex macromolecule whose immunological properties vary with sequence and structure. To determine whether DNA can inhibit immune responses, the effects of mammalian DNA and synthetic phosphodiester (Po) and phosphorothioate (Ps) oligonucleotides (ODNs) on IL-12 production were tested using murine macrophages. With bacterial DNA as a stimulant, calf thymus DNA and human placenta DNA blocked IL-12 production by splenic and bone marrow macrophages. A (dG)(30) Po ODN and all single-base Ps 30 mer ODNs were also effective inhibitors. The Ps ODNs also blocked IL-12 production induced by lipopolysaccharide (LPS) and a stimulatory Ps ODN. With the J774 cell line, single-base Ps ODNs inhibited IL-12 production induced by bacterial DNA, LPS, and a stimulatory Ps ODN. Together, these results indicate that DNA has inhibitory properties, suggesting that mammalian DNA could limit immune activation during inflammation and counteract the effects of bacterial DNA.
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PMID:Inhibition of murine macrophage IL-12 production by natural and synthetic DNA. 1096 37

T-cell activation usually requires at least two signals. The first signal is antigen-specific, and the second signal(s) involves the interaction of a T-cell costimulatory molecule(s) on the antigen-presenting cell (APC) with its ligand on the T cell. Dendritic cells (DCs) are the most potent APCs, attributable, in part, to their expression of several T-cell costimulatory molecules. Human DCs generated in vitro, however, will vary in methods of generation and maturation and in terms of expression of different phenotypic markers-including costimulatory molecules-among different donors. We report here that a recombinant avipox (fowlpox, rF) vector has been constructed that can efficiently express the transgenes for three human T-cell costimulatory molecules (B7-1, ICAM-1, and LFA-3) as a result of individual early avipox promoters driving the expression of each transgene. This triad of costimulatory molecules (designated TRICOM) was selected because each has an individual ligand on T cells and each has been shown previously to prime a unique signaling pathway in T cells. We report here that rF-TRICOM can efficiently infect human DCs of different states of maturity and hyperexpress each of the three costimulatory molecules on the DC surface without affecting other DC phenotypic markers. Infection of influenza or human papilloma virus 9-mer peptide-pulsed DCs from different individuals, or at different stages of maturity with rF-TRICOM, resulted in enhanced activation of T cells from peripheral blood mononuclear cells of autologous donors after 24 h of incubation with DCS: This enhanced activation was analyzed by both titrating the peptide and differing the DC:effector cell ratios. No effect was observed using the control wild-type avipox vector. No increase in apoptosis was observed in T cells hyperstimulated with the TRICOM vector, and no decrease in interleukin-12 production was seen in lipopolysaccharide-stimulated DCs infected with rF-TRICOM. Antibody-blocking experiments demonstrated that enhanced T-cell activation by TRICOM was attributed to each of the three costimulatory molecules. Peptide-pulsed, rF-TRICOM-infected DCs were also shown to be more effective than peptide-pulsed DCs in activating T cells to 9-mer peptides derived from two relatively weak "self" immunogens, i.e., human prostate-specific antigen and human carcinoembryonic antigen. These studies thus demonstrate for the first time that a vector that can simultaneously hyperexpress three costimulatory molecules can be used to efficiently infect human DCs, leading to enhanced peptide-specific T-cell activation. The use of this approach for in vitro studies and clinical applications in immunotherapy is discussed.
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PMID:Enhanced activation of human T cells via avipox vector-mediated hyperexpression of a triad of costimulatory molecules in human dendritic cells. 1132 45

Reaction to certain motifs in bacterial DNA is an important function of natural immunity. For example, single stranded oligonucleotides (ODN) containing the motif "not C, unmethylated C, G, not G" are powerful mitogens and apoptosis inhibitors for mouse spleen B cells. But replacing GCGTT or ACGTT with GCGGG or ACGGG converted a stimulatory 15-mer ODN into an inhibitory ODN. All inhibitory ODN had three consecutive G, and a fourth G increased inhibitory activity, but a deazaguanosine substitution to prevent planar stacking did not affect activity. Inhibitory ODN blocked apoptosis protection and cell-cycle entry induced by stimulatory ODN, but not that induced by lipopolysaccharide, anti-CD40 or anti-IgM+IL-4. ODN-driven up-regulation of cyclin D(2), c-Myc, c-Fos, c-Jun and Bcl(XL) and down-regulation of cyclin kinase inhibitor p27(kip1) were all blocked by inhibitory ODN. The relative potency of a series of stimulatory and inhibitory ODN was the same for all readouts measured. Interference with uptake of stimulatory ODN could not account for their inhibitory effects. Even if addition of inhibitory ODN was delayed several hours, partial inhibition of stimulatory ODN effects occurred. Inhibitory ODN hold potential as antidotes for excessive ODN stimulation in the clinical setting and provide an important tool for studying ODN recognition.
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PMID:Inhibitory oligonucleotides specifically block effects of stimulatory CpG oligonucleotides in B cells. 1198 8

Mammalian myeloid and epithelial cells express various peptide antibiotics (such as defensins and cathelicidins) that contribute to the innate host defense against invading microorganisms. Among these peptides, human cathelicidin CAP18/LL-37 (L(1) to S(37)) possesses not only potent antibacterial activity against gram-positive and gram-negative bacteria but also the ability to bind to gram-negative lipopolysaccharide (LPS) and neutralize its biological activities. In this study, to develop peptide derivatives with improved LPS-neutralizing activities, we utilized an 18-mer peptide (K(15) to V(32)) of LL-37 as a template and evaluated the activities of modified peptides by using the CD14(+) murine macrophage cell line RAW 264.7 and the murine endotoxin shock model. By replacement of E(16) and K(25) with two L residues, the hydrophobicity of the peptide (18-mer LL) was increased, and by further replacement of Q(22), D(26), and N(30) with three K residues, the cationicity of the peptide (18-mer LLKKK) was enhanced. Among peptide derivatives, 18-mer LLKKK displayed the most powerful LPS-neutralizing activity: it was most potent at binding to LPS, inhibiting the interaction between LPS and LPS-binding protein, and attaching to the CD14 molecule, thereby suppressing the binding of LPS to CD14(+) cells and attenuating production of tumor necrosis factor alpha (TNF-alpha) by these cells. Furthermore, in the murine endotoxin shock model, 18-mer LLKKK most effectively suppressed LPS-induced TNF-alpha production and protected mice from lethal endotoxin shock. Together, these observations indicate that the LPS-neutralizing activities of the amphipathic human CAP18/LL-37-derived 18-mer peptide can be augmented by modifying its hydrophobicity and cationicity, and that 18-mer LLKKK is the most potent of the peptide derivatives, with therapeutic potential for gram-negative bacterial endotoxin shock.
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PMID:Augmentation of the lipopolysaccharide-neutralizing activities of human cathelicidin CAP18/LL-37-derived antimicrobial peptides by replacement with hydrophobic and cationic amino acid residues. 1220 46

ISIS 104838 is a 20-mer phosphorothioate antisense oligonucleotide (ASO) that binds tumor necrosis factor-alpha (TNF-alpha) mRNA. It carries a 2'-methoxyethyl modification on the five 3' and 5' nucleotide sugars, with 10 central unmodified deoxynucleotides. ISIS 104838 was identified from a 264 ASO screen in phorbol myristate acetate-activated keratinocytes, and the dose response was assessed in lipopolysaccharide (LPS)-activated monocytes. Healthy males received multiple intravenous (i.v.) ISIS 104838 infusions in a placebo-controlled dose escalation trial (0.1-6 mg/kg). Additional volunteers received single or multiple subcutaneous (s.c.) injections. ISIS 104838 suppressed TNF-alpha protein by 85% in stimulated keratinocytes. The IC50 for TNF-alpha mRNA inhibition in stimulated monocytes was <1 microM. For i.v., C(max) occurred at the end of infusion. The effective plasma half-life was 15 to 45 min at 0.1 to 0.5 mg/kg and 1 to 1.8 h for higher doses. The apparent terminal plasma elimination half-life approximated 25 days. Obese subjects had higher plasma levels following equivalent mg/kg doses. For s.c. injections, C(max) occurred at 2 to 4 h and was lower than with equivalent i.v. dosing. Plasma bioavailability compared with i.v. was 82% following a 200 mg/ml s.c. injection. Transient activated partial thromboplastin time prolongation occurred after i.v. infusions and minimally after s.c. injections. Two subjects experienced rash, one a reversible platelet decrease, and mild injection site tenderness was noted. TNF-alpha production by peripheral blood leukocytes, induced ex vivo by LPS, was decreased by ISIS 104838 (p < 0.01). ISIS 104838, a second-generation antisense oligonucleotide, was generally well tolerated intravenously and subcutaneously. The pharmacokinetics support an infrequent dosing interval. Inhibition of TNF-alpha production ex vivo was demonstrated.
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PMID:Phase I trial of ISIS 104838, a 2'-methoxyethyl modified antisense oligonucleotide targeting tumor necrosis factor-alpha. 1243 59

Depending on sequence and backbone structure, DNA can inhibit as well as stimulate immune responses. As previously shown, single-base phosphorothioate (Ps) oligodeoxynucleotides (ODN) can inhibit murine macrophage activation. To determine whether these compounds can also affect dendritic cells (DC), the effects of 30-mer Ps ODN (SdA, SdT, SdG, and SdC) on DC activation were assessed in an in vitro system. With DC preparations obtained from murine bone marrow cultured in granulocyte macrophage-colony stimulating factor, the Ps ODN blocked the production of interleukin-12 and nitric oxide induced by bacterial DNA, an immunostimulatory cytosine phosphate guanosine dinucleotide (CpG) ODN and lipopolysaccharide (LPS). Furthermore, these compounds inhibited up-regulation of costimulatory molecules CD40 and CD86 as well as major histocompatibility complex-II molecules, indicating an effect on DC maturation. Although the Ps ODN limited uptake of CpG ODN as assessed by flow cytometry, the Ps ODN did not affect LPS uptake, suggesting that these compounds inhibit DC responses by effects on downstream signaling pathways. Together, these observations extend the range of action of inhibitory ODN to DC and suggest a role of these compounds as immunomodulatory agents.
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PMID:Inhibition of murine dendritic cell activation by synthetic phosphorothioate oligodeoxynucleotides. 1248 97

To investigate whether interleukin-1 beta(IL-1 beta), tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS) induce expression of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein in calf aortic smooth muscle cells(SMCs), calf aortic SMCs were cultured by a substrate-attached explant method. The cultured SMCs were used between the third to the fifth passage. After the cells became confluent, the SMCs were exposed to 2 ng/ml IL-1 beta, 20 ng/ml TNF-1 alpha and 100 ng/ml LPS respectively, and the total RNA of SMCs which were incubated for 4 h at 37 degrees C were extracted from the cells by using guanidinium isothiocyanate method. The expression of MCP-1 mRNA in SMCs was detected by using dot blotting analysis using a probe of gamma-32P-end-labelled 35-mer oligonucleotide. After a 24-h incubation, the media conditioned by the cultured SMCs were collected. The MCP-1 protein content in the conditioned media was determined by using sandwich ELISA. The results were as follows: Dot blotting analysis showed that the cultured SMCs could express MCP-1 mRNA. After a 4-h exposure to IL-1 beta, TNF-alpha and LPS, the MCP-1 mRNA expression in SMCs was increased (3.6-fold, 2.3-fold and 1.6-fold, respectively). ELISA showed that the levels of MCP-1 protein in the conditioned media were also increased (2.9-fold, 1.7-fold and 1.1-fold, respectively). The results suggest that calf aortic SMCs could express MCP-1 mRNA and protein. IL-1 beta and TNF-alpha can induce strong expression of MCP-1 mRNA and protein, and the former is more effective than the latter.
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PMID:Interleukin-1 beta, tumor necrosis factor-alpha and lipopolysaccharide induce expression of monocyte chemoattractant protein-1 in calf aortic smooth muscle cells. 1284 52

Endotoxin, also known as lipopolysaccharide (LPS), is the major mediator of septic shock due to Gram-negative bacterial infection. Chemically synthesized S3 peptide, derived from Sushi3 domain of Factor C, which is the endotoxin-sensitive serine protease of the limulus coagulation cascade, was previously shown to bind and neutralize LPS activity. For large-scale production of this peptide and to mimick other pathogen-recognizing molecules, tandem multimers of the S3 gene were constructed and expressed in Escherichia coli. The recombinant tetramer of S3 (rS3-4mer) was purified by anion exchange and digested into monomers (rS3-1mer). Both the rS3-4mer and rS3-1mer were functionally analyzed for their ability to bind LPS by an ELISA-based method and surface plasmon resonance. The LAL inhibition and TNFalpha-release test showed that rS3-1 mer can neutralize the LPS activity as effectively as the synthetic S3 peptide, while rS3-4mer displays an enhanced inhibitory effect on LPS-induced activities. Both recombinant peptides exhibited low cytotoxicity and no haemolytic activity on human cells. This evidence suggests that the recombinant sushi peptides have potential use for the detection, removal of endotoxin and/or anti-endotoxin strategies.
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PMID:Tandem repeats of Sushi3 peptide with enhanced LPS-binding and -neutralizing activities. 1296 81


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