OBJECTIVETo investigate the mechanism of polymyxin B (PMB) antagonizing the biological activity of lipopolysaccharide (LPS).

METHODSThe affinity of PMB for LPS and lipid A was assayed by biosensor, and the neutralization of PMB for LPS (2 ng/ml) was detected by kinetic turbidimetric limulus test. The releases of TNF-alpha and IL-6 in murine peritoneal macrophages a (PMphi) after exposure to LPS (100 ng/ml) were detected, and the expression levels of TLR4, TNF-alpha and IL-6 mRNA in PMphi induced by LPS (100 ng/ml) were measured by RT-PCR.

RESULTSPMB had high-affinity to LPS and lipid A with dissociation equilibrium constants of 18.9 nmol/L and 11.1 nmol/L, respectively, and neutralized LPS in a dose-dependent manner. Furthermore, PMB could markedly inhibit the expressions of TLR4, TNF-alpha and IL-6 mRNA and the release of cycokines in LPS-stimulated murine peritoneal macrophages.

CONCLUSIONSPMB neutralizes LPS and inhibites the expression and release of cycokines in macrophages, in which the affinity of PMB for lipid A plays an important role.

Animals ; Cytokines ; analysis ; Limulus Test ; Lipid A ; antagonists & inhibitors ; Lipopolysaccharides ; antagonists & inhibitors ; Macrophages ; chemistry ; Mice ; Polymyxin B ; pharmacology

OBJECTIVEObserving the time course and establishing the model of kappaB-decoy oligodeoxynucleotides (rcB-decoy) inhibiting the activity of NF-kappaB in the PC12 cells.

METHODSPC12 cells cultivating in the 6 wells plate were divided into 3 groups, experimental group: adding kappaB-decoy complex (6 microg DNA/well), the control group: adding scrambled-decoy complex, the normal group: adding lipid-Lipofectamine 2000, transfer and cultivate 48 h, then lipopolysaccharide (LPS, 200 ng/ml) was added in the cells for 0.5-4 h. The immunocytochemistry and Western blot were used to measure the expression or the activity of NF-kappaB in PC12 cells.

RESULTSIn PC12 cells, compared with normal group, the expression of NF-kappaB enhanced obviously with the time of the stimulation of LPS in scrambled-decoy treated control group (P < 0.01), in 2-4 h the level reached the peak; the expression of NF-kappaB showed the stable level with the time of the stimulation of LPS in kappaB-decoy treated experimental group, compared with the control group, the expression levels were obviously lower than the respective time point of control groups (P < 0.01).

CONCLUSIONkappaB-decoy could reduce the expression of NF-kappaB in the normal PC12 cells and inhibit the activity of NF-cB in the pathologic PC12 cells.

Animals ; Cells, Cultured ; Lipopolysaccharides ; pharmacology ; NF-kappa B ; antagonists & inhibitors ; metabolism ; Oligodeoxyribonucleotides ; pharmacology ; PC12 Cells ; Rats

OBJECTIVETo investigate the lipopolysaccharide (LPS) antagonizing biological activity of densefruit pattany root-bark extract (DPR-2) in vitro.

METHODSThe effect of DPR-2 in neutralizing LPS (0.1 microg/L) was detected by kinetic turbidimetric limulus test. The effect of different concentrations of DPR-2 (0,8.0,16.0,32.0,64.0 mg/L) on binding of FITC-conjugated LPS (FITC-LPS,100.0 microg/L) to murine RAW264.7 cells was analyzed with laser scanning confocal microscopy. The expression of TNF-alpha and IL-6 mRNA in RAW264.7 cells after exposure to LPS (100.0 microg/L) were determined by real-time RT-PCR.

RESULTSDPR-2 could neutralize LPS (P < 0.05 or P < 0.01), and inhibit the binding of FITC-LPS to RAW264.7 cells in a dose-dependent manner when the concentration of DPR-2 was above 16.0 mg/L. Furthermore, DPR-2 could markedly inhibit the expression of TNF-alpha and IL-6 mRNA in LPS-stimulated murine RAW264.7 cells.

CONCLUSIONDPR-2 exhibit an anti-LPS effect in vitro, which may be related to its capacity to neutralize LPS and inhibit binding of LPS for its receptors.

Animals ; Cell Line ; Drugs, Chinese Herbal ; pharmacology ; Endotoxins ; antagonists & inhibitors ; In Vitro Techniques ; Limulus Test ; Lipopolysaccharides ; antagonists & inhibitors ; Mice ; Monocytes ; drug effects ; metabolism ; Plant Extracts ; pharmacology

PURPOSE: Our goal was to investigate the effects of inhibition of transglutaminase 2 (TGase 2) on endotoxin-induced uveitis (EIU) METHODS: EIU was induced in female Lewis rats by single footpad injections of 200 microgram of lipopolysaccharide (LPS). TGase 2 inhibitors were administered intraperitoneally 30 minutes before and at the time of LPS administration. Rats were sacrificed 24 hours after injection, and the effects of the TGase 2 inhibitors were evaluated by the number of intraocular inflammatory cells present on histologic sections and by measuring the TGase 2 activity and TGase products in the aqueous humor (AqH). TGase 2 substrates were also assayed in AqH from uveitis patients. RESULTS: Clinical indications of EIU, the number of cells present on histologic sections, and TGase 2 activity in AqH increased in a time-dependent manner, peaking 24 hours after LPS injection. Inflammation in EIU was significantly reversed by treatment with TGase inhibitors. A 23-kDa cross-linked TGase substrate was identified in the AqH from EIU rats and uveitis patients. MALDI-TOF analysis showed that this substrate in uveitis patients was human Ig kappa chain C region. CONCLUSIONS: TGase 2 activity and its catalytic product were increased in the AqH of EIU rats. TGase 2 inhibition attenuated the degree of inflammation in EIU. Safe and stable TGase inhibitors may have great potential for the treatment of inflammatory uveitis.
Animals ; Disease Progression ; Enzyme Inhibitors/*therapeutic use ; Female ; GTP-Binding Proteins/*antagonists & inhibitors/*metabolism ; Lipopolysaccharides ; Rats ; Rats, Inbred Lew ; Transglutaminases/*antagonists & inhibitors/*metabolism ; Uveitis/chemically induced/*enzymology/pathology

OBJECTIVETo investigate the effect of Angelicae Pubescentis Radix (APR) on the activity of endocannabinoid hydrolase and N-acylethanolamine-hydrolyzing acid amidase (NAAA), and to demonstrate the mechanism of anti-inflammatory effect of APR by in vitro lipopolysaccharide (LPS)-induced inflammation model.

METHODAPR essential oil was extracted by steam distillation, and the chemical components were identified by GC-MS. Enzymatic activity was performed by using recombinant NAAA-overexpressing protein and detected by LC-MS. Lipids were extracted by methonal/chloroform mixure and analyzed by LC-MS. mRNA and protein expression levels of proinflammatory genes were examined by Real time-PCR and ELISA assay kit, respectively. The content of nitro oxide (NO) was detected by Griess reaction.

RESULTTwenty active components were identified from APR essential oil which inhibited NAAA activity in a dose-dependent manner. On the LPS-induced RAW264.7 cells, APR essential oil reversed LPS-suppressed N-palmitoylethanolamide (PEA) contents in a dose-dependent manner and reduced LPS-induced proinflammatory genes, TNF-alpha and IL-6. Moreover, APR essential oil reduced the mRNA expression of iNOS, subsequently reduced the release of NO, a classic inflammatory marker.

CONCLUSIONThe research demonstrated that the effect of APR on inflammation is mediated by the inhibition of NAAA activity, which increase the cellular endobioactor PEA levels and decrease proinflammatory factor. The results suggest that APR can serve as a nature NAAA inhibitor.

Amidohydrolases ; antagonists & inhibitors ; Angelica ; chemistry ; Animals ; Anti-Inflammatory Agents ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Lipopolysaccharides ; pharmacology ; Mice ; Oils, Volatile ; analysis ; pharmacology

BACKGROUNDNumerous studies have shown that reducing the level of tumor necrosis factor-alpha (TNFα) through the use of anti-TNF antibodies or soluble TNF receptor is a safe and efficacious treatment to inflammatory diseases such as rheumatoid arthritis. Therefore, novel approaches to achieve this outcome are desired. The aim of this study was to investigate the characterization of a small molecule inhibitor, Y316, which blocks TNF mRNA upregulation and TNF production by lipopolysaccharides (LPS) stimulated monocytes.

METHODSPeripheral blood mononuclear cells (PBMC) from healthy volunteers were plated in 24-well plates and stimulated with LPS (1 µg/ml), phorbol-12-myristate-13-acetate (PMA) (100 ng/ml), zymosan (10 µg/ml) and Tsst (100 ng/ml). Supernatants were collected after 4-hour culture at 37°C, and quantitative determination of TNFα, interleukin-1β (IL-1β), IL-6, IL-8, IL-10 and IL-2 production in the supernatants was performed by colorimetric enzyme-linked immunosorbent assay (ELISA). Total RNA of PBMC was isolated and cytokine mRNA quantitation was performed by using a RNA level measuring kit (R & D Systems). PBMC were pretreated with Y316 (10 µmol/L, 1 µmol/L, 0.1 µmol/L, 0.01 µol/L and 0.001 µmol/L) or dimethyl sulfoxide at 37°C for 10 minutes, and then stimulated with LPS or PMA, protein concentrations of p44.42, IKBα, P38 and Jun NH2-terminal kinase were determined by Western blotting. Cyclic adenosine-3',5'-monophosphate (cAMP) of PBMC was measured by enzyme immunoassay kit (Amersham Pharmacia Biotech).

RESULTSY316 blocked TNF production and inhibited the upregulation of TNF mRNA levels in response to LPS, and also prevented the production of IL-1 and IL-6. In contrast, Y316 augmented the production of IL-10 in LPS-stimulated monocytes. Y316 failed to prevent the production of IL-2 and TNF in antigen-stimulated T cells, suggesting that its effects may be cell-type specific. Y316 prevented the phosphorylation and activation of the MAPK, ERK, and therefore appeared to mediate its effects on TNF by acting at an early point in the signaling cascade induced in response to LPS. There was no effect of Y316 on cAMP levels either alone or in the presence of LPS.

CONCLUSIONSY316 appears to be a small molecule inhibiting TNF production, which may act via a novel mechanism. Identification of the target of Y316 may lead to the development of alternative strategies for achieving selective cytokine inhibition.

Anti-Inflammatory Agents ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Interleukin-1 ; antagonists & inhibitors ; biosynthesis ; Interleukin-6 ; antagonists & inhibitors ; biosynthesis ; Lipopolysaccharides ; pharmacology ; Monocytes ; drug effects ; immunology ; Phosphorylation ; Tumor Necrosis Factor-alpha ; antagonists & inhibitors ; biosynthesis

Previously, we reported that high glucose enhanced cytokine-induced nitric oxide (NO) production by rat mesangial cells (MCs), and that the enhanced expression of the iNOS pathway may promote extracellular matrix accumulation by MCs. The present study was designed to examine whether the iNOS pathway is pathologically altered in experimental diabetic nephropathy, and whether therapy with angiotensin converting enzyme (ACE) inhibitor (imidapril: I) or angiotensin II type I receptor (AT1) blocker (L-158,809: L), ameliorates these changes. Male Sprague-Dawley rats were injected with diluent (control: C) or streptozotocin. At sacrifice after 4, 8 and 12 weeks, rats underwent either a 4 hour placebo or an intraperitoneal lipopolysaccharide (LPS, 2 mg/kg) challenge. Systolic blood pressure (SBP) and urinary protein excretion (UPE) increased significantly in diabetic (D) rats compared with C. The basal expression of glomerular iNOS mRNA was increased in D rats compared with that of C rats, by reverse- transcription (RT)-polymerase chain reaction (PCR), whereas there was no significant difference in the level of protein by Western blot analysis. Upon LPS stimulation, the iNOS mRNA and protein expression was significantly elevated in D rats. In D rats, this up-regulation, of LPS-stimulated iNOS expression, was equally ameliorated both by I and L in mRNA and protein levels. From immunohistochemistry (IHC), there was a negative staining for the iNOS within the glomeruli of five C rats without LPS treatment, but one of four rats, with LPS treatment, showed minimal iNOS staining in the glomeruli. In D rats, the glomerular mesangium and podocytes were positive for iNOS in each of three out of five rats with, and without, LPS treatment. In conclusion, LPS-stimulated glomerular iNOS expression was enhanced in diabetic pnephropathy, and the activation of angiotensin II may play a role in this enhancement.
Angiotensin-Converting Enzyme Inhibitors/pharmacology ; Animal ; Kidney Glomerulus/*drug effects/*enzymology ; Lipopolysaccharides/*pharmacology ; Male ; Nitric-Oxide Synthase/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Angiotensin/antagonists & inhibitors

OBJECTIVETo investigate the changes in the functional activity of glycogen synthase kinase-3 (GSK-3) in the hepatic tissue after endotoxin (lipopolysaccharide, LPS) tolerance and explore the effects of LPS-induced GSK-3 inhibition on glycogen metabolism in the liver.

METHODSMale SD rats were randomly divided into normal control, endotoxin pretreatment and GSK-3 inhibitor (lithium chloride) groups with corresponding pretreatments prior to a large dose of LPS challenge (10 mg/kg) to induce liver injury. Glycogen deposition and content in the hepatic tissue was detected using periodic acid-Schiff (PAS) staining and a glycogen quantification kit, respectively. Western blotting was performed for semi-quantitative analysis of protein level and inhibitory phosphorylation of GSK-3, and a Coomassie brilliant blue G-250-based colorimetric assay was used to detect calpain activity in the liver.

RESULTSGlycogen content in the liver decreased significantly after LPS challenge in all the 3 groups (P<0.05) but showed no significant difference among the groups (P>0.05). Both LPS and lithium chloride pretreatments caused a significant increase of liver glycogen content (P<0.05). LPS pretreatment induced inhibitory phosphorylation of GSK-3β (P<0.05) and partial cleavage of GSK-3α but did not affect the expression of GSK-3 protein (P>0.05). Large-dose LPS challenge significantly increased the activity of calpain in the liver tissue (P<0.05) to a comparable level in the 3 groups (P>0.05).

CONCLUSIONEndotoxin pretreatment induces inhibitory phosphorylation of GSK-3β and partial cleavage of GSK-3α and promotes the deposition of liver glycogen but does not affect the activity of calpain, which may contribute to an increased glycogen reserve for energy supply in the event of large-dose LPS challenge.

Animals ; Calpain ; metabolism ; Glycogen ; metabolism ; Glycogen Synthase Kinase 3 ; antagonists & inhibitors ; metabolism ; Lipopolysaccharides ; adverse effects ; Lithium Chloride ; pharmacology ; Liver ; drug effects ; metabolism ; pathology ; Male ; Rats ; Rats, Sprague-Dawley

The expression of cDNA encoding Tachyleus auti-lipoposaccharide (LPS) factor, which is of interest for use as a potential inhibitor of the common core subunit of Gram-negative bacterial endotoxin. First, the TALF gene was inserted into expression vectors pGEX-4T-2, pET22b and pET28a to construct recombinant expression plasmids. The recombinant plasmids were transformed to E. coli BL21 (DE3) and the expression of TALF was examined. Results show that TALF in pET22b and pET28a vectors can't be expressed. Only the fusion protein GST-TALF was expressed in E. coli BL21 existing as inclusion bodies. From 1 liter of culture, about 4mg of fusion protein GST-TALF with 91% purity was finally obtained. No apparent bactericidal activity and LPS neutralizing activity of the fusion protein GST-TALF were found. After digested with thrombin, the fusion protein GST-TALF exhibited strong bactericidal activity and LPS neutralizing activity.
Antimicrobial Cationic Peptides ; Arthropod Proteins ; Escherichia coli ; genetics ; Glutathione Transferase ; genetics ; Invertebrate Hormones ; genetics ; pharmacology ; Lipopolysaccharides ; antagonists & inhibitors ; Plasmids ; Recombinant Fusion Proteins ; biosynthesis ; pharmacology

OBJECTIVETo observe the effect of a new synthetic tripeptide [Arg(NO(3))- Lys(OCH(3))- Arg(NO(3))] on L-arginine/NO pathway in the macrophage cell strain RAW246.7.

METHODSThe cultured macrophages exposed to lipopolysaccharide (LPS, 1 microg/L) treatment were randomly divided into 3 groups (n=6) and treated with distilled water, 1x10(-4) mol/L tripeptide and 1x10(-4) mol/L L-arginine, NG-monomethyl-L-arginine (L-NMMA) for 24 h, respectively. The macrophages were incubated for 24 h with LPS (1 microg/L) and in the presence of different concentrations of L-arginine (0 to 2 mmol/L), or in normal culture medium (containing 0.5 mmol/L L-arginine) for 24 h with LPS (1 microg/L) and in the presence of tripeptide of 0 to 10x10(-4) mol/L. The changes of [(3)H]-L-arginine transport and NO production from the macrophages were measured.

RESULTNO release from macrophages incubated in the LPS-containing culture medium was 50 folds, and [(3)H]-L-arginine uptake 2.7 folds that in cells in normal culture medium. Tripeptide (1x10(-4) mol/L) inhibited [(3)H]-L-arginine transport and NO production by 67% and 71% respectively. The effect of tripeptide was stronger than L-NMMA (P<0.05). Extracellular L-arginine caused a concentration-dependent increase in nitrite production, which reached the maximum at concentrations above 0.5 mmol/L Km for nitrite production of 0.162+/-0.015 mmol/L and Vmax of 91.2+/-2.3 micromol/(24h.10(6) cells). L-arginine transport and NO production were inhibited by tripeptide, but their dose-dependent pattern of changes was different with EC50 of 0.21x10(-4) mol/L and 1.27x10(-4) mol/L, respectively.

CONCLUSIONSActivation of macrophages with LPS induces nitrite accumulation in the culture medium, which is dependent on the presence of extracellular L-arginine. The tripeptide induces dysfunction of L-arginine/NO pathway in macrophages, potently inhibits L-arginine transport and competitively combine the active sites of nitric oxide synthase.

Arginine ; metabolism ; Biological Transport ; drug effects ; Cells, Cultured ; Humans ; Lipopolysaccharides ; Macrophages ; cytology ; metabolism ; Nitric Oxide ; biosynthesis ; Nitric Oxide Synthase ; antagonists & inhibitors ; Oligopeptides ; pharmacology