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)

The present study investigated the mechanisms involved in the increased 5-hydroxytryptamine (5-HT) vasoconstriction observed in rat middle cerebral arteries exposed in vitro to lipopolysaccharide (LPS, 10 microg x ml-1) for 1-5 h. Functional, immunohistochemical and Western blot analysis and superoxide anion measurements by ethidium fluorescence were performed. LPS exposure increased 5-HT (10 microm) vasoconstriction only during the first 4 h. In contrast to control tissue, indomethacin (10 microm), the COX-2 inhibitor NS 398 (10 microm), the TXA2/PGH2 receptor antagonist SQ 29548 (1 microm) and the TXA2 synthase inhibitor furegrelate (1 microm) reduced 5-HT contraction of LPS-treated arteries from hour one. The iNOS inhibitor aminoguanidine (0.1 mm) increased 5-HT contraction from hour three of LPS incubation. The superoxide anion scavenger superoxide dismutase (SOD, 100 U ml-1) and the H2O2 scavenger catalase (1000 U ml-1), as well as the respective inhibitors of NAD(P)H oxidase and xanthine oxidase, apocynin (0.3 mm) and allopurinol (0.3 mm), reduced 5-HT contraction after LPS incubation. LPS induced an increase in superoxide anion levels that was abolished by PEG-SOD. Subthreshold concentrations of the TXA2 analogue U 46619, xanthine/xanthine oxidase and H2O2 potentiated, whereas those of sodium nitroprusside inhibited, the 5-HT contraction. COX-2 expression was increased at 1 and 5 h of LPS incubation, while that of iNOS, Cu/Zn-SOD and Mn-SOD was only increased after 5 h. All the three vascular layers expressed COX-2 and Cu/Zn-SOD. iNOS expression was detected in the endothelium and adventitia after LPS. In conclusion, increased production of TXA2 from COX-2, superoxide anion and H2O2 enhanced vasoconstriction to 5-HT during the first few hours of LPS exposure; iNOS and SOD expression counteracted that increase at 5 h. These changes can contribute to the disturbance of cerebral blood flow in endotoxic shock.
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PMID:Mechanisms involved in the early increase of serotonin contraction evoked by endotoxin in rat middle cerebral arteries. 1453 51

Systemic inflammatory response conditions are associated with capillary leak and haemodynamic compromise. Fluid resuscitation to reverse the ensuing hypovolaemia is, however, complicated by the decreased endothelium reflection coefficient to albumin and other colloids. We developed PEG-Alb (albumin covalently linked to polyethylene glycol) as a potential resuscitative agent. PEG was covalently linked to human albumin at multiple sites on the protein. The modified protein was heterogeneous when examined by SDS/PAGE, size-exclusion chromatography and SELDI-TOF MS (surface-enhanced laser-desorption ionization-time of flight MS). Based on size-exclusion chromatography and osmotic pressure data, the effective volume of PEG-Alb is increased 13- to 16-fold compared with unmodified albumin. In an LPS (lipopolysaccharide) model of shock, rats treated with PEG-Alb showed better blood pressure, lower Hct (haematocrit) consistent with haemodilution and less lung injury than rats treated with unmodified albumin or saline. In a CLP (caecal ligation and puncture) model of sepsis, PEG-Alb was more effective than albumin or saline in maintaining blood pressure and in decreasing Hct. When fluorescein-labelled PEG-Alb and Texas Red-labelled albumin were administered to rats with LPS- or CLP-induced shock, PEG-Alb was retained within blood vessels, whereas albumin extravasates into the interstitial space. Based on these data, PEG-Alb appears to be retained within blood vessels in models of capillary leak. PEG-Alb may ultimately be effective in the clinical treatment of shock associated with capillary leak.
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PMID:Plasma expansion by polyethylene-glycol-modified albumin. 1504 8

Five peptides: BPI(85-109); CAP18(106-137); endotoxin inhibitor (EI); GQ33 and GQ33C, derived from lipopolysaccharide (LPS)-binding molecules were investigated for LPS-binding ability with a view to a potential use in extracorporeal therapy. The surface plasmon resonance technique (SPR) was used to monitor the interaction between LPS in solution and the surface-immobilized peptides. The peptides were covalently bound to a model dextran surface via inherent amino groups or via terminally introduced cysteine residues. The results showed that the binding efficacy and binding stability of the peptides varied greatly. The CAP18(106-137) peptide, which exhibited the highest binding efficacy and binding stability, was also immobilized on a poly(ethylene imine)-poly(ethylene glycol) (PEI-PEG) surface through maleimide-terminal PEG. The binding efficacy of the CAP18(106-137) peptide was not significantly affected by the different immobilization methods used in the attachment to a dextran or a PEI-PEG surface. LPS bound selectively to CAP18(106-137) and showed very low unspecific binding to the PEI-PEG surface layer. The EI peptide proved to have a reasonably good binding capacity but a less stable interaction with LPS. The other peptides exhibited much poorer binding efficacy. We believe that the results presented in this work can be of practical value for the development of extracorporeal treatment of patients suffering from septic shock.
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PMID:Lipopolysaccharide removal by a peptide-functionalized surface. 1564 60

Cross-linked hyperbranched fluoropolymer (HBFP) and poly(ethylene glycol) (PEG) amphiphilic networks with PEG weight percentages of 14% (HBFP-PEG14), 29% (HBFP-PEG29), 45% (HBFP-PEG45), and 55% (HBFP-PEG55) were prepared on 3-aminopropyl)triethoxysilane (3-APS) functionalized microscope glass slides for marine antifouling and fouling-release applications. The surface-free energies (gamma(s)), polar (gamma(s)(p) and gamma(s)(AB)), and dispersion (gamma(s)(d) and gamma(s)(LW)) components were evaluated using advancing contact angles by two-liquid geometric-mean and three-liquid Lifshitz-van der Waals acid-base approaches. The HBFP coating exhibited a low surface energy of 22 mJ/m(2), while the gamma(s) and gamma(s)(p) of the cross-linked HBFP-PEG coatings increased proportionally with the PEG weight percentages in the networks. The adsorption of bovine serum albumin (BSA), lectin from Codium fragile (CFL), lipopolysaccharides from Escherichia coli (LPSE) and Salmonella minnesota (LPSS) upon glass, APS-glass, HBFP, PEG, and the cross-linked HBFP-PEG network coatings were investigated by fluorescence microscopy. The marine antifouling and fouling-release properties of the cross-linked HBFP-PEG coatings were evaluated by settlement and release assays involving zoospores of green fouling alga Ulva (syn. Enteromorpha; Hayden, H. S.; Blomster, J.; Maggs, C. A.; Silva, P. C.; Stanhope, M. J.; Waaland, J. R. Eur. J. Phycol. 2003, 38, 277). The growth and release of Ulva sporelings were also investigated upon the HBFP-PEG45 coating in comparison to a poly(dimethylsiloxane) elastomer (PDMSE) standard material. Of the heterogeneous cross-linked network coatings, the maximum resistances to protein, lipopolysaccharide, and Ulva zoospore adhesion, as well as the best zoospore and sporeling release properties, were recorded for the HBFP-PEG45 coating. This material also exhibited better performance than did a standard PDMSE coating, suggesting its unique applicability in fouling-resistance applications.
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PMID:The antifouling and fouling-release performance of hyperbranched fluoropolymer (HBFP)-poly(ethylene glycol) (PEG) composite coatings evaluated by adsorption of biomacromolecules and the green fouling alga Ulva. 1577 83

We describe the fabrication and characterization of poly(ethylene glycol) (PEG) hydrogel spheres containing the enzyme horseradish peroxidase (HRP) for application as optical nanosensors for hydrogen peroxide. HRP was encapsulated in PEG hydrogel spheres by reverse emulsion photopolymerization, yielding spheres with a size range from 250 to 350 nm. Encapsulated HRP activity and sensitivity to hydrogen peroxide were investigated by the Amplex Red assay based on the fluorescence response as a function of H2O2. These HRP-loaded spheres were then introduced to murine macrophages with Amplex Red in the culture media. After phagocytosis, the biocompatibility of spheres was determined by live cell staining using calcein AM (5 microM). The HRP-loaded PEG hydrogel spheres were activated (i.e., fluorescent oxidized Amplex Red produced within the spheres) by oxidative stresses such as exogenous H2O2 (100 microM) and lipopolysaccharide (1 microg/mL), which induced the production of endogenous peroxide inside macrophages. The results presented here indicate that after polymerization, the enzyme activity of HRP was still maintained and that using these HRP-containing nanospheres, peroxide production could be sensed locally within cells.
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PMID:Encapsulation of enzymes within polymer spheres to create optical nanosensors for oxidative stress. 1625 79

In the oral microbial environment, Gram-negative bacterial derived lipopolysaccharide (LPS) can initiate inflammatory bone loss as seen in periodontal diseases. p38 Mitogen-activated protein kinase (MAPK) signaling is critical to inflammatory cytokine and LPS-induced cytokine expression, which may contribute toward periodontal bone loss. The purpose of this proof-of-principle study was to evaluate the ability of an orally active p38alpha MAPK inhibitor (SD-282) to reduce periopathogenic LPS-induced alveolar bone loss in an experimental rat model. Five groups of Sprague-Dawley rats received one of the following treatments: LPS injected to the palatal gingiva adjacent to the maxillary molars three times per week for 8 weeks, LPS plus two doses of SD-282 (15 or 45 mg/kg) twice daily by oral gavage, or control groups given drug vehicle (1% polyethylene glycol) or SD-282 (45 mg/kg) only. Baseline and 8-week alveolar bone loss was assessed by microcomputed tomography (microCT) and histological examination. LPS induced severe bone loss over this time period, whereas control groups were unchanged from baseline measurements. Both doses of SD-282 showed significant protection from LPS-induced bone loss. Bone area and volumetric analysis of maxillas by microCT indicated significant loss of bone volume with LPS treatment, which was blocked with the p38 inhibitor. Histological examination indicated significantly fewer tartate-resistant acid phosphatase-positive osteoclasts and a significant decrease in interleukin (IL)-6, IL-1beta, and tumor necrosis factor alpha expression in p38 inhibitor-treated groups compared with LPS groups by immunostaining. Results from this in vivo study suggest that orally active p38 MAPK inhibitors can reduce LPS-induced inflammatory cytokine production and osteoclast formation and protect against LPS-stimulated alveolar bone loss.
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PMID:A p38alpha selective mitogen-activated protein kinase inhibitor prevents periodontal bone loss. 1704 Oct 6

Lipid rafts on the cell surface are believed to be very important as platforms for various cellular functions. The aim of this study was to know whether defective lipid efflux may influence lipid rafts on the cell surface and their related cellular functions. We investigated macrophages with defective lipid efflux from ATP binding cassette transporter A1-deficient (Abca1-KO) mice. Lipid rafts were evaluated by the following two novel probes: a biotinylated and protease (subtilisin Carlsberg)-nicked derivative of theta-toxin and a fluorescein ester of polyethylene glycol-derived cholesterol. Lipid rafts in Abca1-KO macrophages were increased, as demonstrated by both probes. Moreover, activities of nuclear factor kappaB, mRNA and intracellular distribution, and secretion of tumor necrosis factor-alpha (TNF-alpha) were examined after stimulation by lipopolysaccharides (LPSs). LPS-induced responses of the activation of nuclear factor kappaB and TNF-alpha were more prompt and accelerated in the Abca1-KO macrophages compared with wild-type macrophages. Modification of lipid rafts by cyclodextrin and nystatin corrected the abnormal response, suggesting an association between the increased lipid rafts and abnormal TNF-alpha secretion. We report here that Abca1-KO macrophages with defective lipid efflux exhibited increased lipid rafts on the cell surface and accelerated TNF-alpha secretion.
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PMID:Increased lipid rafts and accelerated lipopolysaccharide-induced tumor necrosis factor-alpha secretion in Abca1-deficient macrophages. 1707 92

Microarrays of single macrophage cell-based sensors were developed and demonstrated for potential real-time bacterium detection by synchrotron FTIR microscopy. The cells were patterned on gold electrodes of silicon oxide substrates by a surface engineering technique, in which the gold electrodes were immobilized with fibronectin to mediate cell adhesion and the silicon oxide background was passivated with polyethylene glycol (PEG) to resist protein adsorption and cell adhesion. Cell morphology and IR spectra of single, double, and triple cells on gold electrodes exposed to lipopolysaccharide (LPS) of different concentrations were compared to reveal the detection capability of this cell-based sensing platform. The single-cell-based system was found to generate the most significant and consistent IR spectrum shifts upon exposure to LPS, thus providing the highest detection sensitivity. Changes in cell morphology and IR shifts upon cell exposure to LPS were found to be dependent on the LPS concentration and exposure time, which established a method for the identification of LPS concentration and infected cell population. Possibility of using this single-cell system with conventional IR spectroscopy as well as its limitation was investigated by comparing IR spectra of single-cell arrays with gold electrode surface areas of 25, 100, and 400 microm2 using both synchrotron and conventional FTIR spectromicroscopes. This cell-based platform may potentially provide real-time, label-free, and rapid bacterial detection, and allow for high-throughput statistical analyses, and portability.
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PMID:Single-cell-based sensors and synchrotron FTIR spectroscopy: a hybrid system towards bacterial detection. 1756 Jul 77

Genetic modification of Gram-negative bacteria to express a desired protein within the cell's periplasmic space, located between the inner cytoplasmic membrane and the outer cell wall, can offer an attractive strategy for commercial production of therapeutic proteins and industrial enzymes. In certain applications, the product expression rate is high, and the ability to isolate the product from the cell mass is greatly enhanced because of the product's compartmentalized location within the cell. Protein release methods that increase the permeability of the outer cell wall for primary recovery, but avoid rupturing the inner cell membrane, reduce contamination of the recovered product with other host cell components and simplify final purification. This article reports representative data for a new release method employing glycol ether solvents. The example involves the use of 2-butoxyethanol (commonly called ethylene glycol n-butyl ether or EB) for selective release of a proprietary biopharmaceutical protein produced in the periplasmic space of Pseudomonas fluorescens. In this example, glycol ether treatment yielded approximately 65% primary recovery with approximately 80% purity on a protein-only basis. Compared with other methods including heat treatment, osmotic shock, and the use of surfactants, the glycol ether treatment yielded significantly reduced concentrations of other host cell proteins, lipopolysaccharide endotoxin, and DNA in the recovered protein solution. The use of glycol ethers also allowed exploitation of temperature-change-induced phase splitting behavior to concentrate the desired product. Heating the aqueous EB extract solution to 55 degrees C formed two liquid phases: a glycol ether-rich phase and an aqueous product phase containing the great majority of the product protein. This phase-splitting step yielded an approximate 10-fold reduction in the volume of the initial product solution and a corresponding increase in the product's concentration.
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PMID:Use of glycol ethers for selective release of periplasmic proteins from Gram-negative bacteria. 1776 Apr 59

Antibodies, having a high specificity for their particular target, are increasingly being used as therapeutic agents with functions including agonist, antagonist, and targeted drug delivery. The use of many biologic therapies, including antibody fragments, is generally limited by their rapid clearance from plasma. A commonly used approach to extend exposure to biologic therapies is the attachment of polyethylene glycol.Tumor necrosis factor (TNF)-alpha is a multifunctional cytokine involved in the regulation of immune responses. Elevated levels of TNFalpha are found in a wide range of diseases, including the chronic inflammatory conditions rheumatoid arthritis, psoriasis, and Crohn disease (CD). Anti-TNFalpha antibodies have proved highly efficacious in the treatment of these conditions. In addition, they have proved invaluable for investigating the role of TNFalpha in disease etiology. Based on evidence showing that neutralizing antibodies to TNFalpha were effective in animal models of CD, anti-TNFalpha antibody treatments were assessed in clinical trials. Interestingly, the anti-TNFalpha antibody etanercept proved ineffective at achieving remission in active CD despite potently neutralizing soluble TNFalpha. This indicated that an additional mode of action is also involved in the efficacy of the anti-TNFalpha agents adalimumab, certolizumab pegol, and infliximab in CD; one suggestion was apoptosis. However, etanercept, like adalimumab and infliximab, can induce apoptosis. Furthermore, certolizumab pegol (which has demonstrated efficacy in CD) does not cause complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, apoptosis, or necrosis of neutrophils, all measured in vitro. These functional differences observed with certolizumab pegol stem from its unique structure that does not include the crystallizable fragment (Fc) portion present in the other anti-TNFalpha agents, and the way in which it signals through membrane TNF. It is well established that bacteria are a major part of the inflammatory process in CD. The property identified that reflected the efficacies of the anti-TNFalpha agents etanercept, adalimumab, certolizumab pegol, and infliximab in CD was the ability to inhibit the cytokine production by monocytes that is induced by bacterial lipopolysaccharide. It may therefore be the case that this mode of action is important for efficacy in CD.
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PMID:A PEGylated Fab' fragment against tumor necrosis factor for the treatment of Crohn disease: exploring a new mechanism of action. 1877 14


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