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

Activation of human umbilical vein endothelial (HUVE) cells with the inflammatory mediators tumour necrosis factor-alpha (TNF), interleukin-1 (IL-1), lipopolysaccharide (LPS) and phorbol esters enhanced their adhesiveness for leucocytes. The appearance of an activation antigen ELAM-1, recognized by a monoclonal antibody (MoAb) ENA1, parallels the kinetics of the enhanced adherence of leucocytes to endothelial cells. Adhesion of polymorphonuclear cells (PMN) to activated HUVE cells could be blocked by F(ab')2 fragments of MoAb ENA1 up to 60%. An additive inhibition of the adhesion was established by pre-incubation of the PMN with anti-CD18 MoAb and/or leucocyte adhesion inhibitor (LAI), produced by endothelial cells. An opposite reaction, however, was observed when HUVE cells were pre-incubated with intact MoAb ENA1, resulting in an enhancement of the adhesion up to 200%. Apparently, the blocking effect of MoAb ENA1 could be bypassed by the strong interaction of the Fc part of the MoAb with the Fc receptor (FcR) on the PMN. Similarly, anti-CD18 MoAb and/or LAI reduced the adhesion observed if intact ENA1 were used, and Fc-FcR interaction took place. The results presented in this study indicate that adhesion via ELAM-1, the CD18 antigen and via the receptor for LAI are different mechanisms. These mechanisms may act in concert to strengthen the binding of PMN to HUVE cells. Moreover, a strong adhesion could be established via the Fc part of MoAbs directed against HUVE cells with the FcR on the PMN. The phenomenon described may play a role in graft rejection and in diseases where antibodies directed against endothelium are involved.
 ...
PMID:Adhesion of polymorphonuclear cells to human endothelial cells. Adhesion-molecule-dependent, and Fc receptor-mediated adhesion-molecule-independent mechanisms. 169

Endothelium is central to the cellular infiltration that develops during inflammation, and a prominent feature of its involvement is the expression of adhesion molecules for circulating leukocytes. In the present study, we assessed the kinetics of endothelial adhesion molecule expression during the cutaneous endotoxin response in baboons. Immunostained cryostat sections and hematoxylin and eosin-stained paraffin sections of skin biopsies were examined using set scoring systems to provide semiquantitative data on the changes in endothelial phenotype and induced polymorphonuclear leucocyte (PMN) accumulation. Endothelium in control skin did not express endothelial leukocyte adhesion molecule (ELAM)-1 but did show a relatively weak expression of intercellular adhesion molecule (ICAM)-1. By 2 hours after injection of endotoxin (500 mcg of Escherichia coli-derived lipopolysaccharide), a marked expression of ELAM-1 developed that was associated with concurrent extensive adhesion and extravasation of PMN. The ELAM-1 expression subsequently decreased and was virtually absent by 9 hours. Mean scores for endothelial expression of ICAM-1 changed comparatively little over this time course, and mononuclear cell accumulation was minimal. The response to endotoxin differs from that to tumor necrosis factor injection; the latter causes sustained ELAM-1 expression, and delayed but pronounced increases in ICAM-1, with accompanying mononuclear cell extravasation. Thus, local endotoxin administration provides a model of acute inflammation in which PMN accumulation is associated with striking endothelial expression of ELAM-1. In this model, appreciable elevations in ICAM-1 expression are unnecessary for PMN infiltration.
 ...
PMID:Recruitment of neutrophils in the local endotoxin response: association with de novo endothelial expression of endothelial leukocyte adhesion molecule-1. 170 5

Baboons were subjected to septic or traumatic/hypovolemic shock and their tissues were examined for the de novo expression of endothelial leukocyte adhesion molecule 1 (ELAM-1), using immunohistochemical techniques. In animals with septic shock induced with live Escherichia coli, there was widespread expression of ELAM-1, recognized by monoclonal antibodies H4/18 or ENA-1 in most tissues examined with strong staining in the lung, liver, and kidneys. Endothelial leukocyte adhesion molecule 1 expression was evident in capillaries, venules, small veins, arterioles, and arteries. In contrast, baboons with traumatic/hypovolemic shock had minimal levels of focal ELAM expression in all organs studied. Similarly evidence of neutrophil activation, measured by granulocyte elastase levels in the plasma was much more pronounced in animals with septic shock. The study documents that lipopolysaccharide (LPS)- and cytokine-induced endothelial activation occurs in vivo in septic shock. Much higher levels of ELAM-1 expression and plasma granulocyte-elastase titer in septic shock, as contrasted with traumatic/hypovolemic shock, are consistent with the higher levels of circulating tumor necrosis factor, other cytokines, and LPS in sepsis.
 ...
PMID:Expression of endothelial leukocyte adhesion molecule-1 in septic but not traumatic/hypovolemic shock in the baboon. 171 43

The sialyl Lewis-x determinant is a ligand for ELAM-1, a major adhesion molecule for HL60 cells and neutrophils. ELAM-1 expression can selectively be induced on human umbilical vein endothelial cells (HUVEC) by tumor necrosis factor, interleukin 1 and lipopolysaccharide. The determinant sialyl Lewis-x is found on both glycolipids as well as on glycoproteins. Using specific inhibitors of the biosynthesis of N-linked glycosylated glycoproteins, we investigated whether N-linked glycans or their modifications are involved in ELAM-1-dependent adhesion of HL60 cells to activated HUVEC. The inhibitors of glycoprotein processing N-methyl-deoxynojirimycin, 1-deoxymannojirimycin and swainsonine did not affect ELAM-1-dependent adhesion. Complex-type N-linked glycans are not required for ELAM-1 mediated adhesion, and therefore the ligand for ELAM-1 is most likely a glycolipid, or a glycoprotein carrying O-linked oligosaccharides.
 ...
PMID:The ligand recognized by ELAM-1 on HL60 cells is not carried by N-linked oligosaccharides. 172 Oct 27

In this in vitro study, the influence of serum-concentration, heat inactivation of the serum and the origin of the serum on the responsiveness of cultured human umbilical vein endothelial cells (HUVEC) to immunological challenges was investigated. Addition of human serum during stimulation with 1 microgram/ml bacterial lipopolysaccharide (LPS) increased endothelial cell ELAM-1 expression and interleukin (IL)-6 release five to ten-fold. Full endothelial cell responsiveness to LPS required 10 to 50% human serum and was largely abrogated after heating the serum for 30 minutes at 56 degrees C. Addition of newborn or fetal bovine serum instead of human serum, induced even higher IL-6 release and ELAM-1 expression in response to LPS, whilst heat-inactivation of these serum-batches only moderately decreased endothelial cell responses. Endothelial cell IL-6 release and ELAM-1 expression after stimulation with IL-1 beta and tumor necrosis factor-alpha (TNF-alpha) were less influenced by heat inactivation of the serum and by omission of serum, whilst responses to PMA remained completely unaffected by such modifications in assay media. Finally, we demonstrated that endothelial cell IL-8 release also and ICAM-1 expression in response to LPS and cytokines were increased by addition of human serum, indicating that the use of serum-free assay media, or the use of media enriched with heat-inactivated (HI) human serum interferes with physiological endothelial cell responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:LPS and cytokine-induced endothelial cell IL-6 release and ELAM-1 expression; involvement of serum. 172 50

Tumor necrosis factor (TNF) induced by bacterial lipopolysaccharide (LPS) was shown to have an important role in precipitation of septic shock and disseminated intravascular clotting (DIC). At the endothelial level TNF down-regulates thrombomodulin (thus preventing protein C formation) and inhibits the production of tissue plasminogen activator (t-PA), thus impairing anticoagulant mechanisms. On the other hand, TNF up-regulates the production of procoagulant factors such as t-PA inhibitor (PAI), tissue factor and platelet activating factor (PAF). These effects create an imbalance between procoagulant and anticoagulant mechanisms, in favor of the former. TNF also activates polymorphonuclears (PMNs), and increases their chemotaxis and adherence to endothelial surfaces by up-regulation of specific endothelial (ELAM-1) and PMN (CDw18) adherence proteins. The damage inflicted by activated PMN to the endothelial cell promotes tissue factor exposure and PAI release, with initiation of the characteristic explosive coagulation process of DIC, facilitated by the dissociation between pro- and anticoagulant mechanisms induced by TNF. These newly discovered mechanisms precipitating septic shock and DIC enable consideration of new treatments for this condition as anti-TNF antibodies or TNF inhibitors, anti-ELAM-1 antibodies anti-tissue factor antibodies, administration of activated factor C, etc. These therapeutic approaches may revolutionize the treatment of septic shock and DIC in the next decade.
 ...
PMID:Role of tumor necrosis factor in the pathogenesis of intravascular coagulopathy of sepsis: potential new therapeutic implications. 199 4

A semi-quantitative procedure is described, which allows the evaluation of expression levels of endothelial adhesion molecules on cultured human umbilical vein endothelial cells (HUVEC) using energy dispersive X-ray microanalysis (EDX). As a model two adhesion molecules, E-selection (CD62E; ELAM-1/endothelial leukocyte adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1; CD54), were localized by the use of the silver-enhancement colloidal gold method after stimulation of HUVEC with endotoxin lipopolysaccharide (LPS), tumour necrosis factor (TNF) or a phorbol ester (PMA). The analysis was performed in a scanning electron microscope (SEM) at an accelerating voltage of 15 kV with scanned areas of 200 x 400 microns. The semi-quantitative data indicated that in LPS-treated groups both adhesion molecules were expressed at a significantly higher level than in all other groups (P < 0.01). In addition, after a 4 h treatment the expression levels of E-selectin in all groups were higher compared to ICAM-1. The experimental data from X-ray microanalysis were compared with data obtained from an enzyme-linked immunosorbent assay (ELISA) and similar values were found for both types of preparation. This microanalytical method is relatively simple and seems to be suitable for immunogold labelling studies on different types of endothelial cells in vitro.
 ...
PMID:Application of X-ray microanalysis to study of the expression of endothelial adhesion molecules on human umbilical vein endothelial cells in vitro. 753 36

Marine fish consumption is known to reduce mortality from ischemic heart disease. The use of fish oil as a dietary supplement, however, is not universally recommended. In large doses, fish oil reduces plasma cholesterol and triacylglycerol but increases low density lipoprotein (LDL) levels and the potential for free radical generation and bleeding. Moderate marine fish consumption is known to reduce mortality without altering commonly measured variables, i.e., plasma cholesterol levels, in vitro platelet aggregation, and bleeding times. In swine, we observed that monocyte adhesions and platelet clumps over the lesion surface of proximal left anterior descending (LAD) coronary arteries are markedly reduced when an atherogenic diet was supplemented with cod-liver oil, even when the cholesterol levels were equalized with the untreated group. These findings suggest that fish oil is hypothrombogenic. We developed an in vitro assay to delineate the mechanism whereby fish oil reduced monocyte-endothelial cell interactions in vivo. The effects of supplementing the culture medium with different fatty acids on adhesions between lipopolysaccharide (LPS) stimulated swine aortic endothelial cells (SAEC) and the human monocyte-like cell line, U937, was investigated in a 10 minute adhesion assay at 37 degrees C. Exposure of SAEC for 6 hours to media containing 50-200 microMs eicosapentaenoic (EPA), stearic, oleic, linoleic, and arachidonic acid, respectively, revealed that only EPA reduced U937-SAEC adhesion. Exposure of U937 to EPA also reduced adhesions. EPA was not effective when added to the SAEC more than 2 hours after they were stimulated with LPS. Exposure of human umbilical vein endothelial cells (HUVEC) to EPA reduced the expression of VCAM-1, ELAM-1, and ICAM-1 after 5 hours of stimulation with LPS. These results suggest that EPA may functionally impair the induction/expression of adhesion molecules.
 ...
PMID:Fish oil, atherogenesis, and thrombogenesis. 753 28

Antisense gene suppression has been carried out for human ICAM-1, ELAM-1, and VCAM-1 in cultured human umbilical vein endothelial cells (HUVEC) stimulated by lipopolysaccharide, tumor necrosis factor alpha, or interleukin-1 beta. A panel of antisense phosphorothioate oligodeoxyribonucleotides (PS-ODN), complementary to mRNA or pre-mRNA of these molecules, were tested for their gene suppression activity monitored by radioimmunoassay of the respective cell surface adhesion molecules. Sequences targeted by effective antisense PS-ODNs were located throughout the mRNA and pre-mRNA. "Hot spots" of gene suppression sites for each region were observed. Shift of the PS-ODN hybridizing site upstream or downstream by a few bases resulted in drastic change of gene suppression efficiency. In addition to translation arrest and RNase H activity, a third mechanism was proposed for antisense gene suppression, involving multiple binding sites for PS-ODN and the activities of RNase H and RNases other than RNase H. Suppression of ICAM-1, ELAM-1, or VCAM-1 in HUVEC by their antisense PS-ODNs resulted in the reduction of adhesion of monocytes and U937 to HUVEC. This may suggest cooperativity among the adhesion molecule pairs in endothelial-leukocyte adhesion, since decrease of a single adhesion molecule on EC surface significantly reduced cell-cell adherence.
 ...
PMID:Antisense gene suppression against human ICAM-1, ELAM-1, and VCAM-1 in cultured human umbilical vein endothelial cells. 755 71

In many diseases, tissue hypoxia occurs in conjunction with other inflammatory processes. Since previous studies have demonstrated a role for leukocytes in ischemia/reperfusion injury, we hypothesized that endothelial hypoxia may "superinduce" expression of an important leukocyte adhesion molecule, E-selectin (ELAM-1, CD62E). Bovine aortic endothelial monolayers were exposed to hypoxia in the presence or absence of tumor-necrosis factor alpha (TNF-alpha) or lipopolysaccharide (LPS). Cell surface E-selectin was quantitated by whole cell ELISA or by immunoprecipitation using polyclonal anti-E-selectin sera. Endothelial mRNA levels were assessed using ribonuclease protection assays. Hypoxia alone did not induce endothelial E-selectin expression. However, enhanced induction of E-selectin was observed with the combination of hypoxia and TNF-alpha (270% increase over normoxia and TNF-alpha) or hypoxia and LPS (190% increase over normoxia and LPS). These studies revealed that a mechanism for such enhancement may be hypoxia-elicited decrements in endothelial intracellular levels of cAMP (<50% compared with normoxia). Addition of forskolin and isobutyl-methyl-xanthine during hypoxia resulted in reversal of cAMP decreases and a loss of enhanced E-selectin surface expression with the combination of TNF-alpha and hypoxia. We conclude that endothelial hypoxia may provide a novel signal for superinduction of E-selectin during states of inflammation.
 ...
PMID:Hypoxia enhances stimulus-dependent induction of E-selectin on aortic endothelial cells. 869 47


1 2 3 Next >>